HB3 - Electrical and Electronic Drawing_noPW

SAA/SNZ HB3:1996

Handbook

Electrical and electronic drawingpractice for students

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© Copyright STANDARDS AUSTRALIA/STANDARDS NEW ZEALAND

Users of Standards are reminded that copyright subsists in all Standards Australia and Standards New Zealand publications andsoftware. Except where the Copyright Act allows and except where provided for below no publications or software produced byStandards Australia or Standards New Zealand may be reproduced, stored in a retrieval system in any form or transmitted by anymeans without prior permission in writing from Standards Australia or Standards New Zealand. Permission may be conditional on anappropriate royalty payment. Australian requests for permission and information on commercial software royalties should be directedto the head office of Standards Australia. New Zealand requests should be directed to Standards New Zealand.

Up to 10 percent of the technical content pages of a Standard may be copied for use exclusively in-house by purchasersof the Standard without payment of a royalty or advice to Standards Australia or Standards New Zealand.

Inclusion of copyright material in computer software programs is also permitted without royalty payment provided suchprograms are used exclusively in-house by the creators of the programs.

Care should be taken to ensure that material used is from the current edition of the Standard and that it is updated whenever theStandard is amended or revised. The number and date of the Standard should therefore be clearly identified.

The use of material in print form or in computer software programs to be used commercially, with or without payment, or incommercial contracts is subject to the payment of a royalty. This policy may be varied by Standards Australia or StandardsNew Zealand at any time.

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Electrical and electronic drawingpractice for students

PUBLISHED JOINTLY BY:

STANDARDS AUSTRALIA STANDARDS NEW ZEALAND1 The Crescent, Level 10, Standards House,

Homebush NSW 2140 Australia 155 The Terrace,Wellington 6001 New Zealand

ISBN 0 7337 0246 5

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SAA/SNZ HB3 :1996 2

INTRODUCTION

Electrical and electronic drawings communicate precise information on a specializedsubject. They use the language of technical drawings which is a combination of symbols,conventions and a uniform approach to preparing and reading drawings. A technical drawingis a specification. As the term ‘specification’ implies, the drawing deals with specifics—information that is precise, unambiguous and presented efficiently.

This Handbook was prepared to help students and educators to acquire skills in electricaland electronic drawing and to understand the approach to drawing. It also provides anintroduction to the relevant Standards.

The Handbook was prepared by the Joint Standards Australia/Standards New ZealandCommittee TE/13 on Symbols, Units and Quantities for Electrotechnology. Particularrecognition is accorded to the outstanding contribution of Mr Vaughan Williamson of theSchool of Electrical Engineering, Illawarra Institute of Technology, N.S.W., who broughttogether existing and original material to form this edition of the Handbook. The input of allcontributors and reviewers of the document is appreciated.

The Handbook draws heavily from the AS/NZS 1103 series of Standards titled Preparation ofdocuments used in electrotechnology. Other Standards which are referenced are also listedbelow. As the contents of the Handbook is a summary of the Standards and otherinformation, there is a limitation to the amount of detail which can be presented. For a moredetailed understanding of the subject, reference should be made to the source documentslisted below.

Acknowledgment is made for the material drawn from the following documents:

International Standard Australian/New Zealand equivalent

Designation Title Designation Title

IEC 1082

(series)

Preparation of documents used in

electrotechnology

AS/NZS 1103*

(series)

Preparation of documents

used in electrotechnology

IEC 617

(series)

Graphical symbols for diagrams AS 1102 and

AS/NZS 1102

(series)

Graphical symbols for

electrotechnology

IEC 445 Identification of equipment

terminals and of terminations of

certain designated conductors,

including general rules of an

alphanumeric system

—

BS 5583 Specification for low voltage

switchgear and controlgear for

industrial use.

—

IEC 750 Item designation in

electrotechnology

AS 3702 Item designation in

electrotechnology

Appendix A provides a description of Standards and other reference material which arerelated to electrical and electronic drawing.

THIS HANDBOOK SHOULD ONLY BE USED FOR STUDENT INSTRUCTION.

STANDARDS AUSTRALIA AND STANDARDS NEW ZEALAND CANNOT ACCEPT ANYLIABILITY FOR ANY CONSEQUENCES THAT MAY ARISE FROM THE USE OF THISHANDBOOK IN LIEU OF THE STANDARDS FROM WHICH EXTRACTS HAVE BEENTAKEN.

* In the course of preparation.

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CONTENTS

Page

CHAPTER 1 TYPES OF ELECTRICAL DRAWINGS

1.1 TYPES OF DRAWINGS—GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.2 TYPES OF DRAWINGS AND RELATED DOCUMENTS . . . . . . . . . . . . . . . . . . . 51.3 DIAGRAM LAYOUT METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

CHAPTER 2 BASIC PRINCIPLES OF DRAWING

2.1 DRAWING SIZES AND IDENTIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282.2 SIZE OF DRAWING SHEETS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282.3 TYPES OF LINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302.4 DIMENSIONS OF LINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302.5 LINE SPACING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302.6 LINE DENSITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302.7 TYPICAL APPLICATION OF LINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302.8 LETTERS AND NUMERALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362.9 METHODS OF INDICATING SYMBOL LOCATION . . . . . . . . . . . . . . . . . . . . . . . 412.10 REPRESENTATION OF OPERATIONAL STATE . . . . . . . . . . . . . . . . . . . . . . . . 422.11 COLOUR ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432.12 TITLE BLOCK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432.13 MATERIAL OR PARTS LISTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

CHAPTER 3 ITEM DESIGNATION

3.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453.2 ITEM IDENTIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453.3 LOCATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463.4 TERMINALS AND CONDUCTORS—DESIGNATIONS . . . . . . . . . . . . . . . . . . . . 463.5 HIGHER LEVEL ASSIGNMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523.6 QUALIFYING SYMBOL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523.7 SEQUENCE OF SECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

CHAPTER 4 CIRCUIT DIAGRAMS

4.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 544.2 CONTENTS OF A CIRCUIT DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 544.3 LAYOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 544.4 LOCATION REFERENCE SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574.5 METHODS OF THE REPRESENTATION OF COMPONENTS AND

CONNECTIONS IN DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574.6 SYMBOLS WITH A LARGE NUMBER OF TERMINALS . . . . . . . . . . . . . . . . . . . 654.7 UNUSED PARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 694.8 DISTRIBUTED CONNECTIONS (WIRED-AND, WIRED-OR) . . . . . . . . . . . . . . . 694.9 LAYOUTS OF COMMONLY USED FUNDAMENTAL CIRCUITS . . . . . . . . . . . . 704.10 SIMPLIFICATION TECHNIQUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 734.11 NOTES ON DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 804.12 ORIENTATION OF CONTACT SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 844.13 REPRESENTATION OF SUPPLY CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . 844.14 REPRESENTATION OF COMBINED ELECTRICAL AND NON-ELECTRICAL

CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 864.15 INTERRUPTED LINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

CHAPTER 5 INTERCONNECTION DIAGRAMS AND TABLES

5.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 885.2 INTERCONNECTION DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 885.3 TYPES OF DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 895.4 INTERCONNECTION TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

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Page

CHAPTER 6 UNIT WIRING DIAGRAMS AND TABLES

6.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 956.2 ITEM DESIGNATION AND MARKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 956.3 LAYOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 956.4 VIEW OF EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 956.5 COMPONENTS, DEVICES AND PARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 956.6 TERMINALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 966.7 WIRING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 966.8 UNIT WIRING TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 996.9 EXAMPLES OF WIRING DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

CHAPTER 7 OVERVIEW DIAGRAMS

7.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1077.2 LAYOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1077.3 OVERVIEW DIAGRAMS FOR CONTROL SYSTEMS FOR NON-ELECTRICAL

PROCESSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

CHAPTER 8 PRINCIPLES OF ORTHOGRAPHIC DRAWINGS

8.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1138.2 IDENTIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1138.3 TYPES OF PROJECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1148.4 ORTHOGONAL PROJECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

CHAPTER 9 PICTORIAL DRAWINGS

9.1 AXONOMETRIC PROJECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1199.2 CHOICE OF AXES FOR ISOMETRIC DRAWINGS . . . . . . . . . . . . . . . . . . . . . . . 1209.3 ISOMETRIC PROJECTION — ADDITIONAL INFORMATION . . . . . . . . . . . . . . 121

CHAPTER 10 DRAWING GRAPHS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

CHAPTER 11 NOTES ON DRAWING PRODUCTION

11.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12611.2 EQUIPMENT REQUIRED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12611.3 DRAWING TECHNIQUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12711.4 DRAWING REPRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12811.5 NOTES ON COMPUTER-AIDED DRAFTING (CAD) EQUIPMENT AND

SOFTWARE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12811.6 CAD TECHNIQUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13011.7 ORIGINAL DRAWINGS AND MAGNETIC MEDIA . . . . . . . . . . . . . . . . . . . . . . . . 131

APPENDICESA LIST OF STANDARDS AND REFERENCE MATERIAL . . . . . . . . . . . . . . . . . . . 133B ITEM DESIGNATION—LIST OF LETTER CODES FOR THE DESIGNATION

OF KIND OF ITEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136C EXAMPLES OF CIRCUIT DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137D GRAPHICAL SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156E SELECTED QUANTITIES AND THEIR LETTER SYMBOLS . . . . . . . . . . . . . . . . 185F EXERCISES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

Originated as SAA HB3 — 1982.

Previous edition 1986.

Jointly revised and designated SAA/SNZ HB3:1996.

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CHAPTER 1

TYPES OF ELECTRICAL DRAWINGS

1.1 TYPES OF DRAWINGS—GENERAL

A technical drawing is a document presenting information in a graphical manner which mayinclude text.

An individual drafting officer may not be required to prepare all types of electrical drawings,but may be required to refer to other types of drawings. The main types of electricaldrawings are summarized below.

1.2 TYPES OF DRAWINGS AND RELATED DOCUMENTS

1.2.1 General

Australian/New Zealand Standard Series AS/NZS 1103 contains definitions of typicaldocuments encountered in an electrical drawing office. These are as follows:

1.2.2 Function-oriented documents

Function-oriented documents show functional behaviour. Examples of these are:

(a) Overview diagram

A relatively simple diagram, often using single line representation, showing the maininterrelations or connections among the items within a system, subsystem, installation,part, equipment, software or similar. (See Figures 1.1 and 1.2.)

(b) Block diagram

An overview diagram using block symbols predominantly.

(c) Network map

An overview diagram showing a network on a map, for example, generating andtransforming stations and power lines, telecommunication equipment and transmissionlines. (See Figure 1.3.)

(d) Function diagram

A diagram showing details of the theoretical or ideal operation of a system,subsystem, installation, part, equipment, software or similar by means of theoretical orideal circuits without necessarily taking into account the means used forimplementation. (See Figure 1.4.)

(e) Logic-function diagram

A function diagram that predominantly uses symbols for binary logic elements.

(f) Equivalent-circuit diagram

A function diagram showing equivalent circuits, used as an aid for the analysis andcalculation of characteristics or behaviour.

(g) Function chart

A chart describing the functions and behaviour of a control system, using steps andtransitions.

(h) Sequence chart (or table)

A chart (or table) showing the succession of operations or status of the units of asystem, the operations or status of the individual units being listed in one direction andthe process steps or time being plotted at a right angle to that. (See Figure 1.5.)

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SAA/SNZ HB3 :1996 6

FIGURE 1.1 EXAMPLE OF AN OVERVIEW DIAGRAM WITH FUNCTIONAL LAYOUT—

A STEELWORKS

FIGURE 1.2 EXAMPLE OF AN OVERVIEW DIAGRAM WITH FUNCTIONAL LAYOUT—

A RADIO RECEIVER

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FIGURE 1.3 EXAMPLE OF A NETWORK MAP — A HIGH VOLTAGE OVERHEAD LINE

WITH A TRANSFORMER STATION AND A 400 V BRANCH

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FIGURE 1.4 EXAMPLE OF A LOGIC-FUNCTION DIAGRAM—TIMING PULSE

GENERATOR EQUIPMENT

(i) Time sequence chart

A sequence chart with the time axis plotted to scale.

(j) Circuit diagram

A diagram showing the implementation of the circuits of a system, subsystem,installation, part, equipment, software or similar, depicting parts and connections bymeans of graphical symbols arranged to show the functions, but without necessarilytaking into account the physical sizes, shapes, or locations of the items.(See Figures 1.6, 1.7 and 1.8.)

(k) Terminal function diagram

A diagram for a functional unit showing the terminals for the interface connections anda description of the internal functions. These may be described by means of a circuitdiagram, simplified if applicable, a function diagram, a function or sequence chart, ortext. (See Figures 1.9 and 1.10.)

(l) Program diagram, table or list

A diagram, table or list showing in detail the program elements, modules and theirinterconnections, so arranged that the interrelations are clearly recognizable.(See Figure 1.11.)

(m) Single-line diagram or one-line diagram

These show the equivalent of a simplified circuit diagram by single lines and graphicsymbols. They are frequently used with drawings of polyphase power circuits, whereall phases in a circuit start and terminate at the same location. For example seeFigure C15.

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FIGURE 1.5 EXAMPLE OF A TIME SEQUENCE CHART — THE CONTROL OF A DRIVE

SYSTEM

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FIGURE 1.6 EXAMPLE OF A CIRCUIT DIAGRAM USING ATTACHED

REPRESENTATION—A DRIVE SYSTEM FOR TWO DIRECTIONS OF ROTATION

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FIGURE 1.7 EXAMPLE OF A CIRCUIT DIAGRAM USING SEMI-ATTACHED

REPRESENTATION—SAME DRIVE SYSTEM AS IN FIGURE 1.6

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FIGURE 1.8 EXAMPLE OF A CIRCUIT DIAGRAM USING DETACHED

REPRESENTATION— SAME DRIVE SYSTEM AS IN FIGURES 1.6 AND 1.7

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NOTE: A1, A2, 1, 4 and 3 are terminal numbers

FIGURE 1.9 EXAMPLE OF A TERMINAL FUNCTION DIAGRAM—SCREENED

ELECTROMECHANICAL RELAY

NOTE: + − are terminals for a 24 V d.c. supply to internal equipment

FIGURE 1.10 EXAMPLE OF A TERMINAL FUNCTION DIAGRAM—FUNCTIONAL UNIT

FOR DETECTING OVERCURRENT

(n) Ladder diagrams

These diagrams are a subset of circuit diagrams which have found particularapplication with relay and programmable controller circuits. The ladder diagrams areso named because of their appearance which consists of at least two vertical lines(usually considered as the power supply rails), between which are placed thehorizontal ‘rungs’ which contain input devices on the left and output coils on the right.Usually, these diagrams will be produced as part of software packages involved withprogrammable controllers. Provision is usually made for rung and instructioncomments, and extra features in software packages include cross reference tables. Adisadvantage of some software packages is that the manufacturer’s symbols are usedrather than Australian or New Zealand Standards Symbols which are based onInternational Electrotechnical Commission Standards.

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NOTES:

1 5/B etc., are sheet references of other drawings

2 211ST etc., are wire numbers

FIGURE 1.11 EXAMPLE OF A PROGRAM DIAGRAM FOR AN INDUSTRIAL PROGRAMMABLE

CONTROLLER — A PROGRAM FOR THE CONTROL OF THREE SETS OF DRIVE EQUIPMENT

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1.2.3 Location documents

Location documents show the position of plant or components. Examples of these are:

(a) Site plan

A plan showing the location, in relation to ’setting-out points’, of construction works,service networks and roadworks, and information on landscape, means of access andthe general layout of the site. (See Figure 1.12.)

(b) Installation drawing or plan

A drawing or plan showing the location of the components of an installation.(See Figures 1.13, 1.14, 1.15 and 1.16.)

(c) Installation diagram

An installation drawing showing the connections between items. (See Figure 1.13.)

(d) Assembly drawing

A drawing representing the spatial position and shape of a group of assembled parts,normally to scale.

(e) Arrangement drawing

An assembly drawing simplified or supplemented to give information needed for aparticular purpose. (See Figures 1.17 and 1.18.)

(f) Printed circuit board diagram

A diagram showing the artwork required to lay out a circuit on a printed circuit boardwhich serves the dual purpose of mounting and interconnecting the electroniccomponents.

(g) Printed circuit overlay

A drawing similar to a component location drawing, in that it shows the physicalplacement of components on a printed circuit board, but it will also normally show a‘shadow’ view of the printed circuit underneath. For a double-sided board, thecomponent side and printed circuit etchings would need to be clearly identified.

NOTES:

1 Location documents should have a clear layout to facilitate reading and understanding of the containedinformation.

2 Non-electrical objects should only be shown if the information is important for the understanding of thedocument and for the proper erection of the electrical installation. This is particularly important if there is atendency to overcrowd the document with unnecessary details. If non-electrical objects are shown theyshould be presented in such a way that they are clearly distinguishable from the electrical objects.

3 Any conductors should be drawn in single-line representation as described in Clauses 4.5(g) and (h).Multiline representation should only be used if it is necessary to explain complicated connection details.

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NOTE: Symbols for engineering survey drawings are contained in AS 1100.401, Technical drawing —Engineering survey and engineering survey design drawing. Symbols on this drawing may differ fromAS 1100.401

FIGURE 1.12 EXAMPLE OF A SITE PLAN—AN INDUSTRIAL PLANT

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FIGURE 1.13 EXAMPLE OF AN INSTALLATION DIAGRAM (DRAWING) WITH

TOPOGRAPHICAL LAYOUT—LIGHTING INSTALLATION IN A BUILDING

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FIGURE 1.14 EXAMPLE OF AN INSTALLATION DRAWING—PART OF A FACTORY

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FIGURE 1.15 EXAMPLE OF AN INSTALLATION PLAN—A SWITCHGEAR ROOM WITH

ASSEMBLIES OF SWITCHGEAR AND CONTROLGEAR

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FIGURE 1.16 EXAMPLE OF AN INSTALLATION DRAWING—AN ELECTRICALLY

POWERED ROBOT

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FIGURE 1.17 EXAMPLE OF AN ARRANGEMENT DRAWING—THE SWITCHGEAR AND CONTROLGEAR ASSEMBLY +A IN FIGURE 1.15

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FIGURE 1.18 EXAMPLE OF AN ARRANGEMENT DRAWING—PRINTED CIRCUIT BOARD

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1.2.4 Connection documents

Connection documents provide information on physical connections among, for example,components, devices, assemblies and installations. Connection documents are used whenassembling, installing or maintaining equipment. Examples of these are:

(a) Connection diagram or table

A diagram or table showing or listing the connections of an equipment installation.

(b) Unit connection diagram or table

A connection diagram or table showing or listing the connections within aconstructional unit. (See Figure 1.19.)

FIGURE 1.19 EXAMPLE OF A UNIT CONNECTION DIAGRAM—A SUBASSEMBLY IN A

CONTROLGEAR ASSEMBLY

(c) Interconnection diagram or table

A connection diagram or table showing the connections between differentconstructional units. (See Figure 1.20.)

(d) Terminal connection diagram or table

A connection diagram or table showing the terminals of a constructional unit and theinternal or external connections to the terminals. (See Figure 1.21.)

(e) Cable diagram, table or list

A diagram, table or list providing information on cables, such as the identification ofthe conductors, the location of the ends and, if needed, the characteristics, routes andfunction. (See Figure 1.22.)

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NOTE: Cables have a cable number (e.g. 112) and core numbers (e.g. 3)

FIGURE 1.20 EXAMPLE OF AN INTERCONNECTION DIAGRAM—PART OF AN

INSTALLATION INCLUDING, TWO TERMINAL STRIPS = A1 −X1

AND =A1−X2, LOCATED IN THE CONSTRUCTIONAL UNITS +A AND +B

FIGURE 1.21 EXAMPLE OF TERMINAL CONNECTION DIAGRAM—A CONTROL UNIT

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NOTE: ... indicates a range of numbers, in this case, 1...5 is 1 to 5

FIGURE 1.22 EXAMPLE OF A CABLE DIAGRAM—CABLE INSTALLATION FOR THE

ASSEMBLIES +A1, +A2 AND +A3

1.2.5 Item lists

Item lists provide details for parts. These are:

(a) Parts list

A list specifying the items (parts, components, software, equipment and similar) thatconstitutes an assembly (or subassembly) and if necessary, the reference documents.(See Figure 1.23.)

(b) Spare parts list

A list specifying the items (parts, components, software, bulk material and similar), forpreventive and corrective maintenance.

1.2.6 Installation-specific documents

Documents giving instructions or information regarding the installation conditions and thesupply, delivery, off-loading, erection and testing of a system, installation, equipment orcomponent.

1.2.7 Commissioning-specific documents

Documents giving instructions or information regarding the commissioning of a system,installation, equipment or component and stating prior adjustments, simulation modes,recommended setting values, and actions to be taken in order to achieve properdevelopment and functioning.

1.2.8 Operation-specific documents

Documents giving instructions or information regarding the operation of a system,installation, equipment or component.

1.2.9 Maintenance-specific documents

Documents giving instructions or information regarding maintenance procedures; forexample in maintenance or service manuals, for a system, installation, equipment orcomponent.

1.2.10 Reliability- and maintainability-specific documents

Documents giving information on the reliability and maintainability of a system, installation,equipment or component.

1.2.11 Graphic drawings

These present mathematical and other technical data in pictorial form, such as charts orgraphs. Such drawings can be used to display design calculations, to compare valuesvisually, and to display test results.

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1.2.12 Technical sketches

These drawings are often used in preliminary design stages and can be hand drawn. Theirpurpose is to enable concepts, dimensions, early costing or similar to be carried out before acommitment is made on the preparation of working drawings. The preliminary sketching ofdetails to determine the feasibility of ideas can save many hours of unnecessary drawing.Many drawings will begin as a technical sketch. Even sketches will require a title, date,drafting officer’s name and job number for identification purposes, to ensure traceability ofdesign details at later stages of a project.

1.2.13 Other documents

Other documents may be necessary, such as handbooks, guides, catalogues, and drawingand document lists.

1.3 DIAGRAM LAYOUT METHODS

1.3.1 Functional layout

A layout method in which the symbols for the components or their parts are placed in thediagram, so that the functional relations can be easily recognized. (See Figures 1.1, 1.2, 1.4,1.7, 1.8 and 4.6.)

1.3.2 Topographical layout

A layout method in which the symbols for the components are placed so that their relativepositions in the diagram correspond to the relative physical locations of the components.(See Figures 1.3. and 1.13.)

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FIGURE 1.23 EXAMPLE OF A PARTS LIST — PUMPING SYSTEM =W1P1

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CHAPTER 2

BASIC PRINCIPLES OF DRAWING

2.1 DRAWING SIZES AND IDENTIFICATION

2.1.1 Drawing sheets and sizes

Details of drawing sheets are given in Clause 2.2.

The choice of drawing sizes should be decided after taking into account the following:

(a) Volume and complexity of the design.

(b) Level of knowledge of personnel who will use the diagrams.

(c) Using a smaller sized sheet and increasing the number of sheets.

(d) Requirements of filing and handling.

(e) Requirements of microfilming.

(f) Requirements of computer-aided design or plotter.

2.2 SIZE OF DRAWING SHEETS

2.2.1 Preferred sizes

The preferred sizes of drawing sheets are the ISO-A series for which the designation anddimensions are as given in Table 2.1.

Preferred size drawing sheets, with slightly wider borders to take account of preprintingconsiderations, shall have dimensions as given in Table 2.2. Such sheets are additionallydesignated by the prefix R, i.e. RA0, RA1, RA2, RA3 and RA4.

Where drawing sheets of a greater length are required, they should be selected from, andhave dimensions in accordance with, one of the series given in Table 2.3. Such sheets aredesignated A3 x 3, A3 x 4, A4 x 3, A4 x 4, and A4 x 5.

NOTE: ISO refers to the International Organization for Standardization.

2.2.2 Non-preferred sizes

The non-preferred sizes of drawing sheets are the ISO-B series for which the designationsand dimensions are as given in Table 2.4.

Non-preferred size drawing sheets, with slightly wider borders to take account of preprintingconsiderations, shall have dimensions as given in Table 2.5. Such sheets shall beadditionally designated by the prefix R, i.e. RB1, RB2, RB3 and RB4.

2.2.3 Roll drawings

Standard widths of roll drawings are 860 mm and 610 mm. Lengths of the roll drawingsheets shall be determined to suit the requirements of the individual drawing.

NOTE: Care should be taken to ensure that the chosen length of a roll drawing is suitable for microfilming (seeAS 1203, Microfilming of engineering documents) and for folding purposes.

2.2.4 Tolerances

The cut sizes in Tables 2.1 to 2.5 shall be subject to the following tolerances:

(a) For dimensions ≤600 mm, ±2 mm.

(b) For dimensions >600 mm, ±3 mm.

Neither diagonal of any cut sheet shall exceed the diagonal of the appropriate maximumlength and width, nor shall it be less than the diagonal of the appropriate minimum lengthand width.

For the purpose of checking the sheet sizes, the material shall be conditioned at 20 ±2°C ata relative humidity of 65 ±2% and measured under these conditions.

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TABLE 2.1

DIMENSIONS OF PREFERREDSHEETS

Standard

designation

Cut sheet dimensions

mm

A0

A1

A2

A3

A4

841 × 1 189

594 × 841

420 × 594

297 × 420

210 × 297

TABLE 2.2

DIMENSIONS OF PREFERRED SHEETSWITH WIDER BORDERS

Designation Cut sheet

dimensions

mmOrdering purposes only Standard

RA0

RA1

RA2

RA3

RA4

A0

A1

A2

A3

A4

860 × 1 220

610 × 860

430 × 610

305 × 430

215 × 305

TABLE 2.3

DIMENSIONS OF ELONGATEDPREFERRED SHEETS

DesignationCut sheet dimensions

mm

A3 × 3

A3 × 4

A4 × 3

A4 × 4

A4 × 5

420 × 891

420 × 1 189

297 × 630

297 × 841

297 × 1 051

TABLE 2.4

DIMENSIONS OF NON-PREFERREDSHEETS

DesignationCut sheet dimensions

mm

B1

B2

B3

B4

707 × 1 000

500 × 707

353 × 500

250 × 353

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TABLE 2.5

DIMENSIONS OF NON-PREFERRED SHEETSWITH WIDER BORDERS

Designation Cut sheet

dimensions

mmOrdering purposes only Standard

RB1

RB2

RB3

RB4

B1

B2

B3

B4

733 × 1 019

510 × 723

361 × 510

255 × 361

2.3 TYPES OF LINES

Lines on drawings shall be selected according to their application. Preferred line types areshown in Table 2.6 and shall be selected from one of the line groups given in Figure 2.1.Each type is designated by a letter. Typical applications are shown in Figures 2.2 and 2.3.

2.4 DIMENSIONS OF LINES

2.4.1 Thickness

The thickness of lines shall be selected from one of the line groups given in Figure 2.1, andshall be such that the thickness of any line after reproduction shall be not less than 0.18 mm.

2.4.2 Dashes

The length and spacing of dashes shall be consistent, but they may vary in length dependingon the complete length of the line and size of the drawing. Recommended dimensions areshown in Table 2.6.

2.5 LINE SPACING

Parallel lines shall be drawn with a clear space between them of not less than twice thethickness of the thickest line, with a minimum space of 1 mm.

Where a group of parallel lines intersect another group of parallel lines, the space betweenlines in each group should be not less than 2 mm.

2.6 LINE DENSITY

To facilitate good quality reproduction of drawings using dyeline or microfilming processes,all lines on original drawings shall be matt, of constant density and have a high contrast withrespect to the material background.

2.7 TYPICAL APPLICATION OF LINES

2.7.1 Type A

Type A lines shall be used for the following purposes:

(a) Visible outlines of features of an object. (See Figure 2.3.)

(b) General details of structures.

(c) Landscaping and existing buildings in survey drawing.

(d) Busbars and transmission paths in electrotechnology. (See Figure 2.4.)

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TABLE 2.6

LINES AND APPLICATIONS

1 2 3 4 5

Designating

letterType of line Example of line Typical application

Examples of

application

(Figure Nos)

A Continuous — thick Visible outlines

General details

Existing buildings

Landscaping in site plans

Busbars and transmission paths

2.3

—

2.2

—

—

M Continuous — medium See Note 1 —

B Continuous — thin Fictitious outlines

Imaginary intersection of surfaces

Dimension lines, projection lines,

intersection lines and leaders

Hatching and outlines of revolved

sections

Fold and tangent bend lines

Short centre-lines

General purpose electrical

conductors and symbols

2.3

—

2.3

—

—

2.3

—

2.4

C Continuous — thin, free-hand Break lines (other than on an axis) 2.3

D Continuous — thin, ruled with

zig-zag

Break lines (other than on an axis) 2.3

E Dashed — thick (see Note 2) Hidden outlines

Hidden edges

—

—

N Dashed — medium (see Note

2)

See Note 1

F Dashed — thin (see Note 2) Hidden outlines

Jumper connections magnetic or

electric screen

2.3

—

G Chain — thin Centre-lines and axes of solid

Pitch lines

Path lines for indicating movement

Features in front of a cutting plane

Indication of repeated detail

Developed views

Material to be removed

2.3

—

2.3

2.3

—

—

H Chain — thick at ends and at

change of direction

— thin elsewhere

Cutting planes 2.3

J Chain — thick Indications of surfaces to comply

with special requirements

Pipelines, drains, services

2.3

2.2

K Chain — thin, double dashed Outlines of adjacent parts

Alternative and extreme position of

movable parts

Centroidal lines

Tooling

2.3

2.3

—

—

NOTES:

1 It is desirable to restrict line thickness to two on any one drawing. A medium thickness line may be used by some drafting disciplines, such

as electrical, for additional clarity.

2 It is recommended that only one thickness of dashed line be used.

3 Proportions of spaces are as specified for Type G.

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2.7.2 Type B

Type B lines shall be used for the following purposes:

(a) Fictitious outlines, such as minor diameters of external threads and major diameters ofinternal threads. (See Figure 2.3.)

(b) Dimension lines and projection lines. (See Figure 2.3.)

(c) Hatching. (See Figure 2.3.)

(d) Leaders. (See Figure 2.3.)

(e) Outlines of revolved sections. (See Figure 2.3.)

(f) Imaginary intersection of surfaces. Such lines should not meet the outlines.

(g) Fold or tangent bend lines.

(h) Short centre-lines, if Type G lines are not appropriate. (See Clause 2.7.6.)

(i) General purpose electrical conductors and symbols. (See Figure 2.4.)

(j) Line of intersection of principal planes.

2.7.3 Types C and D

Lines of Types C and D shall be used to terminate part views and part sections.

Type C is recommended for short break lines and for the S-break in cylindrical members inexterior views. Type D is recommended for long break lines and shall extend beyond theoutline which they terminate.

Both types may be used in the one view. (See Figure 2.3.)

2.7.4 Type E

Type E lines shall be used to indicate hidden outlines and hidden edges.

2.7.5 Type F

Type F lines shall be used to indicate hidden outlines of internal features of an object thatare not otherwise shown or, where their use would assist or is necessary in the interpretationof the drawing.

Features located behind transparent materials shall be treated as hidden parts.

It is important to guard against excessive use of hidden outlines. They should be confined tothe view or views in which they are needed.

The following are further requirements in the use of Type F lines:

(a) Hidden outlines should always begin and end with a dash in contact with the visible orhidden outline at which they start and end, except where such a dash would form acontinuation of a visible outline.

(b) Dashes should join at corners, and arcs should start with dashes at the tangent points.

(c) Dashes of parallel hidden outlines, when close together, should preferably bestaggered.

2.7.6 Type G

Type G lines shall be used for centre-lines and pitch lines, and for indicating features in frontof a cutting plane. They may also be used for indication of repeated details.

Centre-lines of a feature should not intersect in the spaces between dashes.

Centre-lines should project for a short distance beyond relevant outlines and, wherenecessary for dimensioning or correlation of views, they may be extended. For shortcentre-lines, Type G lines should be used with a long dash passing through the feature anda short dash at each end. A Type B line may be used for a short centre-line where there isno space for a dash or where there is no confusion with other types of lines.

This line can be used for developed views.

Type G lines shall be used to show material to be removed, such as locating or holdingbosses and lugs which are subsequently cut off.

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FIGURE 2.1 LINE GROUPS

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FIGURE 2.2 TYPICAL APPLICATION OF TYPES OF LINES—SURVEY

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FIGURE 2.3 TYPICAL APPLICATION OF TYPES OF LINES—MECHANICAL

FIGURE 2.4 TYPICAL APPLICATION OF TYPES OF LINES—

ELECTROTECHNOLOGY

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2.7.7 Type H

Type H lines shall be used to indicate the location of cutting planes in sectioning and, theviewing position for removed views and removed partial views. The short, arrowed leadersindicating direction of viewing position should be located with the arrow touching and normalto the thick ends of the Type H lines. (See Figure 2.3.)

2.7.8 Type J

Type J lines shall be used to indicate that portion of a surface which has to comply withsome special requirement. For example, Figure 2.3 requires a surface which has to complywith some special tolerance requirement or requires special surface treatment such assurface hardening detailed by a note.

2.7.9 Type K

Type K lines shall be used for the following purposes:

(a) Outlines of adjacent parts (see Figure 2.3). Where an adjacent part is shown insection, hatching should be shown, only to avoid confusion and then only along theoutlines.

(b) Alternative and extreme positions of movable parts. (See Figure 2.3.)

(c) Centroidal lines.

(d) Tooling outlines. Alternatively, the component outline where tool drawings areinvolved.

2.8 LETTERS AND NUMERALS

2.8.1 Character shapes and proportions

(a) General

Characters shall be uniform and capable of being produced at reasonable speed byhand, stencil, machine or other means. They shall remain legible and unambiguous ina direct photocopy print, in a reduced copy and as an image on a microfilm-viewingscreen.

Characters shall be of simple form and preferably without serifs and otherembellishments, and shall not be of exaggerated proportions.

NOTE: Clarity, style, size and spacing are important, particularly for numerals as, unlike letters, they rarelyfall into self-identifying patterns and hence are read individually.

(b) Basic form

The basic form of letters and numerals should proportionally conform to thoseillustrated in Figures 2.5 and 2.6.

(c) Freehand characters

Although it is recognized that slight variations will naturally occur with freehandcharacters, the characters should, as much as possible, conform to the basic formsgiven in Figures 2.5 and 2.6.

(d) Stencil characters

Suitable stencilled characters include the following types:

(i) Upright Gothic.

(ii) Sloping Gothic.

(iii) ISO 3098-1 Type B Upright.

(iv) ISO 3098-1 Type B Sloping.

(v) Microfont.

NOTES:

1 See Figures 2.5 to 2.9 inclusive.

2 ISO 3098-1 Type A characters which have a height equal to 14 times the line thickness are not normallyused in Australia/New Zealand.

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(e) Machine-made characters

Machine-made characters as produced by mechanical means or a transfer processshould generally comply with the basic requirements specified.

2.8.2 Height of characters

The height (h) in millimetres (see Figures 2.5 to 2.9 inclusive) of characters should be one ofthe following:

2.5 3.5 5 7 10 14 20

NOTES:

1 For special requirements, other heights may be used, provided that the minimum height complies with therequirements of this Clause.

2 The height of lettering used for tolerances (e.g. +0.5 −0) shall be the same height as the particulardimension to which they are applying.

3 The minimum heights of characters have been selected to be suitable for microfilming purposes.

The recommended height of the characters should be not less than the height stated inTable 2.7 for the sheet sizes indicated. Where the drawing is to be reduced, the characterheight (h) shall be selected so that the height as reproduced is not less than 1.7 mm.

TABLE 2.7

RECOMMENDED MINIMUM HEIGHT OF CHARACTERSON DRAWINGS

Character use

Character height (h), mm

Sheet size

A0, B1 A1, A2, A3, A4 B2, B3 & B4

Titles and drawing numbers 7 5

Subtitles, headings, view and section designations 5 3.5

General notes, material lists, dimensions 3.5 2.5

NOTE: The recommended minimum character heights are for upper-case lettering only. For

upper-case and lower-case combinations, the minimum character height should be one size larger

than that specified.

2.8.3 Thickness of character lines

The maximum thickness of the lines used to form the characters shall be 0.1h, where h is theheight of the characters as shown in Figures 2.5 and 2.6 and as specified in Clause 2.8.2.The line thickness of both lower-case and upper-case letters shall be the same (to facilitatelettering).

FIGURE 2.5 UPRIGHT GOTHIC (ROMAN) CHARACTERS

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FIGURE 2.6 SLOPING GOTHIC (ITALIC) CHARACTERS

* Either of these characters is acceptable by ISO, but ‘a’ and ‘7’ are not recommended for use inAustralia/New Zealand.

FIGURE 2.7 ISO 3098-1 TYPE B UPRIGHT CHARACTERS

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2.8.4 Spacing

(a) Spacing of characters

Characters forming a word or a number should be spaced so that the distancebetween the characters (see Figure 2.10) is approximately twice the thickness of theline forming such characters or 1 mm, whichever is the greater.

Numerical values shall be expressed in accordance with AS 1000 or ISO 1000.

(b) Space between words

The space between words shall be not less than 0.6h and should be not more than 2h.

(c) Space between lines of lettering

The space between lines of lettering shall be not less than 0.6h.

2.8.5 Use of characters

Only one style of character should be used, generally, throughout a drawing. Verticalcharacters should be used for titles, drawing numbers, and reference numbers.

Upper-case letters should be used. Lower-case letters shall be used for conventional signsand symbols normally requiring such characters, e.g. mm, kg, kPa.

Underlined lettering should be avoided. Special emphasis, where required, may be given bythe use of larger characters, or a change of style.

Where necessary for clarity or to prevent misinterpretation between upper-case ‘I’ andlower-case ‘l’ and the numeral ‘1’, serifs may be added.

The letters ‘O’ and ‘I’ should not be used in combination with numbering owing to the liabilityof confusion with the numerals ‘0’ and ‘1’.

All characters in a drawing shall be kept clear of lines.

NOTE: Where a line precludes this requirement, the line may be interrupted sufficiently to accommodatecharacters (see Figure 2.11).

*Either of these characters is acceptable by ISO, but ‘a’ and ‘7’ are not recommended for use in

Australia/New Zealand.

FIGURE 2.8 ISO 3098-1 TYPE B SLOPING CHARACTERS

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FIGURE 2.9 MICROFONT CHARACTERS

FIGURE 2.10 SPACING OF CHARACTERS

FIGURE 2.11 CHARACTERS CLEAR OF LINES

2.8.6 Decimal form

(a) Decimal sign

The decimal sign for technical drawings and associated documents should be the dot,either on the line or at midheight. (See Figure 2.12.)

The diameter of the dot should be twice the thickness of the line used to form thecharacter, and shall be not less than the line thickness. It should be given a fullcharacter space.

NOTES:

1 The preferred location of the dot is on the line.

2 The decimal comma is commonly used in some countries.

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(b) Decimal fractions

Where the quantity is less than unity, the decimal sign shall be preceded by zero (0).(See Figure 2.12.)

0 . 45FIGURE 2.12 EXAMPLE OF DECIMAL FRACTION

2.8.7 Vulgar fractions

The minimum height of the numerator and denominator of a vulgar fraction shall be as givenin Clause 2.8.2, and should be separated by a horizontal line. Where space is limited, asloping line may be used.

2.9 METHODS OF INDICATING SYMBOL LOCATION

2.9.1 General

There are several satisfactory methods of indicating symbol location. The grid referencesystem finds general application. Some other methods are applicable to circuit diagrams.

2.9.2 Grid reference system

When the grid reference system is used, each sheet is divided into rectangular zones whichare identified, for example, by numbers from left to right (columns) and letters from top tobottom (rows). (See Figure 2.13.)

The width and height of the zones will depend on the size of the sheet and may depend onthe complexity of the diagram.

The location of each symbol or circuit in a diagram should be indicated by the number andletter of the zone containing the symbol or circuit. In certain cases, it may be sufficient to useonly a column or row designation. (See Table 2.8.)

2.9.3 Other systems

For special kinds of circuit diagrams, the tabular system, the circuit reference system or theline reference system may be used. (See Chapter 4.)

If there is risk of confusing the grid reference of the symbol with other designations referringto the actual equipment, the grid reference should be written in parentheses.

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FIGURE 2.13 GRID REFERENCE SYSTEM

TABLE 2.8

EXAMPLES OF REFERENCING IN A GRID REFERENCE SYSTEM

Referred item Written reference

Row E on the same sheet E

Column 2 on the same sheet 2

Rectangular zone E2 on the same sheet E2

Rectangular zone E2 on sheet 34 of the same diagram

(i.e. with the same drawing number)

34/E2

Rectangular zone E2 of single-sheet diagram No 4568 Diagram 4568/E2

Rectangular zone E2 on sheet 34 of diagram No 5796 Diagram 5796/34/E2

2.10 REPRESENTATION OF OPERATIONAL STATE

2.10.1 Normal requirements

Apparatus shall be shown in the de-energized or unoperated position or state, or in theposition with no operating force applied, e.g. relay contacts shall be shown in thede-energized state of the relay.

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It is essential that parts of a multiswitching device be shown in a mutually consistent positionor state, irrespective of whether the circuit is in the unoperated condition or not.

2.10.2 Special requirements

To avoid ambiguity, a special indication should be provided on the diagram (e.g. by a note ora chart)—

(a) for apparatus which may rest in any one of two or more positions or states; or

(b) if it is essential to show a circuit in a particular operated position or state.

Switches controlling emergency, standby, alarm circuits and the like, should be shown in thepositions which they occupy during normal service of the equipment or in a specific definedcondition, e.g. aircraft on the ground.

Test switches and similar devices should be shown in the normal position, not in the testposition. (See Figure 2.14.)

(a) Symbol (b) Description

One three-pole switch,

manually operated

Multiline equivalent

FIGURE 2.14 SWITCH — SHOWN IN NORMAL POSITION

2.11 COLOUR ABBREVIATIONS

Where it is desired to indicate colours on a diagram, the abbreviations in Table 2.9 shouldbe used.

2.12 TITLE BLOCK

The title block should be in the bottom right-hand corner of the drawing sheet and theinformation contained may include the following:

(a) Name of the project.

(b) The part of the project depicted.

(c) The type of drawing.

(d) Date.

(e) Drawing number.

(f) Scale.

(g) Drawn by, checked, approved, issued (signature spaces).

(h) Client, or contractor, or organization.

A typical title block is shown in Figure 2.15.

2.13 MATERIAL OR PARTS LISTS

Where several parts are detailed on the one sheet or an assembly of parts is shown, atabulated material or parts list should be provided. This list may be provided above the titleblock (see Figure 2.16), or, if the list is extensive, a separate sheet may be used.

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TABLE 2.9

LETTER CODES FOR COLOURS

Colour Letter code

Black BK

Brown BN

Red RD

Orange OG

Yellow YE

Green GN

Blue (including light blue) BU

Violet (purple) VT

Grey (slate) GY

White WH

Pink PK

Gold GD

Turquoise TQ

Silver SR

Green-and-yellow GNYE

NOTE: The following abbreviations are superseded by the IEC

conventions presented in Table 2.9. They are presented only for the

interpretation of older drawings.

FIGURE 2.15 EXAMPLE TITLE BLOCK

FIGURE 2.16 EXAMPLE PARTS LIST

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CHAPTER 3

ITEM DESIGNATION

3.1 GENERAL

This Chapter provides basic information on item designation. For a complete understandingof this subject, reference should be made to AS 3702, Item designation in electrotechnology.

On an electrical diagram, item designations are used to identify plant, equipment or specificitems depending on the kind of information required. The different sections of an itemdesignation provide information for the following purposes:

(a) Higher level assignment, showing correlation of equipment and function.

(b) Location of an item.

(c) Identification of an item.

(d) Terminal and conductor marking.

Item designation (the identification) of electrical equipment in a plant is generallyaccomplished by the use of a code consisting of a sequence of capital letters or numbers ora combination of both. The codes which are created for the different sections of an itemdesignation may often have a similar format, therefore a system of qualifying symbols areused to identify these different sections of an item designation.

In the following item designation codes, A stands for letter(s) and N for number(s).

Because of the use of automatic data processing equipment, the same meaning is applied toupper-case and lower-case letters.

On most diagrams, an appropriate section of the complete item designation is sufficient toidentify an item of plant and equipment or its location.

NOTE: Refer to Appendix B for the recommended list of ‘kind of item’ letter codes.

3.2 ITEM IDENTIFICATION

3.2.1 General

In a circuit diagram, it is necessary to identify each item of equipment. The item identificationconsists of three parts used in the following order:

A N A

(a) KIND of item. (See Clause 3.2.2.)

(b) NUMBER of the item. (See Clause 3.2.3.)

(c) FUNCTION of the item. (See Clause 3.2.4.)

3.2.2 Kind

The graphical symbol on a diagram provides information about an item, so this partgenerally consists of one letter denoting the kind of item or equipment being identified, suchas a transformer (T), relay (K) or transistor (V).

The recommended list of ‘kind of item’ code letters is shown in Appendix C. If alternativecode letters are used, they should be recorded or shown on the diagram.

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3.2.3 Number

The number is used to identify each item on a drawing, generally being allocated in asequence 1 to n. The numbers can be used to identify the item regardless of the kind of itemcode or to distinguish between similar items within the same letter code. (See Figure 3.1.)

An additional number separated by a point (.) may be used to distinguish between similarparts of an item which may be shown separately on a drawing, such as contact sets on arelay.

3.2.4 Function

Information about the function of an item may be added to the first two parts. Because of thevariety of functions an item such as a relay can perform, it is not possible to create astandard list of functions, so this coding should be explained on a drawing.

Example: Using this procedure of item identification, the item designation for a simpleelectronic circuit would be as shown in Figure 3.1.

3.3 LOCATION

In large plants or complicated equipment, it is necessary to identify the location of items ofelectrical equipment, (an example of such could be a motor driving an air compressor, whereit may be desired to enable the installation of a bearing temperature detector and theconnection of the associated cabling or wiring). The location section of the designation isdeveloped by assigning first a code, either letters or numbers, to a main piece or type ofequipment, then further characters to indicate specific subcategories of the equipment. Thissequence of characters will then provide a specific location identification. Since the locationcodes will be developed individually for each project, it is necessary to illustrate the locationcode assignments on the drawings for the project. An example of a location code forequipment in a cubicle is given in Figure 3.2.

3.4 TERMINALS AND CONDUCTORS—DESIGNATIONS

3.4.1 General

Terminal designations (identifications) should correspond to the markings on the item ofequipment. Where terminals or conductors are not marked and markings are considerednecessary, guidelines are presented for identification.

For the identification of equipment terminals and terminations of conductors, use can bemade of one or more of the following methods:

(a) The physical or relative location of the equipment terminals or of terminations ofcertain designated conductors in accordance with an established system for therelevant product.

(b) A colour code for equipment terminals and terminations of certain designatedconductors in accordance with an established system for the relevant product.

(c) Graphical symbols in accordance with AS 1104. If additional symbols are required,these shall be consistent with the AS 1102 and AS/NZS 1102 series, see Appendix A.

(d) An alphanumeric notation in accordance with the system laid down in Clause 3.4.3.

3.4.2 Application of identification means

The identifying colour, graphical symbol or alphanumeric notation shall be located on, oradjacent to, the corresponding terminal.

When more than one identification method is used and confusion is possible, the correlationbetween the methods shall be clarified in associated documentation.

3.4.3 Marking principles

Terminal marking is based on the following principles:

(a) The two end points of a single element are distinguished by consecutive referencenumbers, the odd number being lower than the even number, for example 1 and 2 inFigure 3.3.

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(b) The intermediate points of a single element are distinguished by reference numbers,preferably in a naturally ascending sequence, for example 3, 4, 5 etc. The referencenumber chosen for intermediate points shall be higher than those chosen for the endpoints; their numbering commences at the point which lies closest to the end point withthe lower reference number. Thus, for example, the intermediate points of an elementwith the end points 1 and 2 will be denoted by the reference numbers 3, 4, and so on.(See Figure 3.4.)

(c) If several similar elements are combined in a group of elements, then one of thefollowing methods for marking the elements shall be used:

(i) The two end points and intermediate points, if any, are distinguished by letterspreceding the reference numbers referred to in (a) and (b). For example U, V,W correspond to the phases of a three-phase a.c. system in Figure 3.5(a).

(ii) The two end points and intermediate points, if any, are distinguished bynumbers preceding the reference numbers referred to in (a) and (b) where aphase identification is not necessary or possible. To avoid confusion, thesenumbers shall be separated by a full stop. For example the end points of oneelement may be marked 1.1 and 1.2, those of another element 2.1 and 2.2.(See Figure 3.5(b).)

(iii) The two end points of each element are distinguished by different consecutivenumbers, the odd number of each element being lower than the even numberof this element (for example see Figure 3.5(c)).

(d) Similar groups of elements having the same reference letters are distinguished by anumerical prefix to the reference letters (for example Figures 3.6(a) and 3.6(b)).

NOTE: Figure 3.7 illustrates the interconnection of equipment terminals and certain designated conductorsmarked in accordance with the alphanumeric notation.

(e) Marking of equipment terminals intended for certain designated conductors Equipmentterminals which are intended to be connected directly or through intermediateequipment to certain designated conductors shall be marked with reference lettersaccording to Table 3.1.

(f) Identification of terminations of certain designated conductors The alphanumericidentification of terminations of certain designated conductors shall be in accordancewith Table 3.1.

NOTE: The items have been numbered consecutively

with reference to similar components, e.g. C1, C2, C3,

R1, R2.

NOTE: The items have been numbered consecutively

as they appear on the diagram without reference to

similar components, e.g. C1, R2, R3, R4, V5, C6.

FIGURE 3.1 EXAMPLES OF ITEM IDENTIFICATION

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FIGURE 3.2 LOCATION CODE FOR EQUIPMENT IN A CUBICLE

TABLE 3.1

MARKING OF EQUIPMENT TERMINALS FOR CONDUCTORS ANDIDENTIFICATION OF TERMINATIONS OF THOSE CONDUCTORS

Designated conductor

Alphanumeric notation

Equipment

terminal markingRemarks

Identification

of conductor

terminations

Remarks

Supply a.c. system conductors

Phase 1 U L1

Phase 2 V L2

Phase 3 W L3

Neutral N N

Supply d.c. system conductors

Positive C L+

Negative D L−

Mid-wire M M

Protective conductor PE PE

PEN-conductor — PEN

Earthing conductor E E

Low noise earth conductor TE TE

Frame or chassis connection MM see Note MM see Note

Equipotential connection CC see Note CC see Note

NOTE: These identifications shall apply only when the terminals or conductors are not intended to be at the

potential of the protective conductor or earth

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FIGURE 3.3 SINGLE ELEMENT WITH TWO TERMINALS

FIGURE 3.4 SINGLE ELEMENT WITH FOUR TERMINALS— TWO ENDPOINTS AND

TWO INTERMEDIATE POINTS

(a) Three-phase equipment with six terminals (b) Three-element equipment with 12 terminals: six

endpoints and six intermediate points

(c) Switching device

FIGURE 3.5 GROUP OF ELEMENTS

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(a) Three-phase equipment with two groups of elements

(b) Two-phase equipment with two groups of elements with four terminals each

FIGURE 3.6 ELEMENTS IN SIMILAR GROUPS

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FIGURE 3.7 INTERCONNECTION OF EQUIPMENT TERMINALS AND DESIGNATED

CONDUCTORS

3.4.4 Terminal marking rule for relay contacts The contactor terminal marking of acontactor relay is formed, in principle, by two digits.

(a) Function number The unit number (or right most digit) is a function number, asfollows:

(i) 1 − 2 for break-contacts.

(ii) 3 − 4 for make-contacts.

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(b) Sequence number The figure of the tens (or left most digit) is a continuous sequencenumber beginning with 1, independent of the contact function.

Terminals belonging to the same contact are marked with the same sequence number.

For contactor relays having 10 contact elements, the sequence number 10 shall bereplaced by 0.

(c) Numbering method The contact numbering is made without any break, from left toright on the device; for devices with tiers, the numbering begins with the tier next tothe mounting level as shown in the following example.

3.5 HIGHER LEVEL ASSIGNMENT

In similar manner to location codes, higher level assignments can be developed inaccordance with the requirements of each project and should be explained on the drawings.However, these should also follow the general format of NANA (the alphanumeric systemdefined in Clause 3.1) to distinguish major functions with the first number; successivesubdivisions being denoted by alphabetic and numeric characters. The higher levelassignment for pump 2 cooling system of turbine 5, would be 2T5.

3.6 QUALIFYING SYMBOL

The codes developed for the various sections of the item designation all have a similarNANA structure, so qualifying symbols are used as a preface to the codes to distinguishbetween sections of the item designation. The qualifying symbols used for the sections ofthe item designation and the order in which the sections are used are listed as follows:

Section Qualifier Information

1 = Higher level assignment

2 + Location

3 − Item identification

4 : Terminal

The qualifying symbol may be omitted or replaced by a note on a diagram if there is noambiguity such as in connection tables and parts lists, where the columns have a titledefining the information provided.

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3.7 SEQUENCE OF SECTIONS

Where a complete item designation is required, its sections should be arranged in the orderof sections as above (i.e. = + − :). Where sections of the item designation are not required,these can be omitted but the same sequence of sections should be maintained.

Examples:

(a) Complete item designation in which the higher level assignment is used to indicate thelocation of the item in the complete plant.

=R016 +3A2 −Q1 :3

Terminal 3

Circuit-breaker 1

Unit 3, subassembly 2

Room 016

(b) Item designation in which the higher level assignment is used to indicate the purposeof the item in the complete plant.

=2T5 −M3

Motor 3

Pump 2 cooling system of turbine 5

(c) The use of qualifying symbols in Figure 3.3 allows the inclusion of location informationwithout confusion.

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CHAPTER 4

CIRCUIT DIAGRAMS

4.1 GENERAL

A circuit diagram shall show the details of the implementation of any system, subsystem,installation, equipment or similar, but need not take into account the physical sizes, shapesor locations of the constituent items. It shall present information necessary for—

(a) understanding the functioning of a circuit (supplementary information such as charts,tables, program documents, other diagrams, etc. may be required);

(b) preparation of connection documents (constructional design information may also berequired.);

(c) testing and fault location (additional documents such as handbooks or connectiondocuments may be required); and

(d) installation and maintenance.

Examples of circuit diagrams are shown in this Chapter as well as in Appendix C.

4.2 CONTENTS OF A CIRCUIT DIAGRAM

A circuit diagram shall contain—

(a) graphical symbols representing the components or functions of the circuit;

(b) representations of the connections among those components or functions;

(c) item designations;

(d) terminal designations;

(e) signal-level conventions applicable to logic signals;

(f) information necessary to trace paths and circuits (signal designations, locationreferences); and

(g) supplementary information necessary for the understanding of the functions.

A circuit diagram for a control system of a power plant or an industrial plant should alsoshow the main circuits to such an extend that the study of the function of the controllingsystem is facilitated. It may often be sufficient to show the main circuits, or part of them, insingle-line representation. In certain cases, however, it may be necessary to use multilinerepresentation, for example, to show how measuring transformers are connected. (SeeClause 4.5 on representations.)

4.3 LAYOUT

4.3.1 General

Graphical symbols and circuits should be arranged to emphasize the process or signal flowand the functional relations according to Clause 4.3.2. Topographical information may beadded, if relevant, but should not govern the layout.

To emphasize the signal flow, the connecting lines of the circuits should be kept as straightas practicable. For certain fundamental circuits, the layouts referred to in Clause 4.9 shouldbe adopted.

To emphasize the functional relations, the symbols for functionally related items should begrouped close to one another. (See Figure 4.1.)

The two requirements may, in some cases, lead to different results, and priority has to begiven to one of the following:

(a) Within functional groups, and for equipment of limited size and complexity, priorityshould be given to the signal flow.

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(b) For systems and complex equipment, the overall function-oriented structure should beemphasized and priority given to the functional grouping. The signal flow between thefunctional groups may thus be more complicated than within the groups.

Parallel paths of equal importance should be symmetrically displaced with respect to thecommon path. (See Figure 4.2.)

Similar items in parallel vertical (horizontal) paths should be aligned horizontally (vertically).(See Figure 4.3.)

4.3.2 Layout of diagrams

The most important consideration in the preparation of a diagram is the adoption of a clearlayout that facilitates understanding.

(a) Signal flow direction

For overview, function and circuit diagrams, the principal direction of flow should befrom left to right or, alternatively, from top to bottom. However, most block symbols forsignal processing, and symbols for binary logic and analogue elements are designedfor a signal flow from left to right. Therefore, circuits with such symbols should bearranged with regard to this (see Figure 4.4). Note the non-preferred bottom to topsignal flow in the 2nd diagram.

If the flow direction for individual signals is not obvious, the connecting lines shall beprovided with arrowheads (see Figure 4.5). These arrowheads shall not touch anycomponent symbol.

(b) Arrangement of symbols

For the functional or topographical layout methods (see Clauses 1.3.1 and 1.3.2),symbols and circuits should be arranged in order to emphasize either functionalrelationship or physical location.

In a diagram with a functional layout, functionally related symbols should be groupedand placed as close to one another as the requirements of annotation and theavoidance of overcrowding will allow. The circuits should be arranged, if applicable, inthe order in which they operate.

In a diagram representing a control system, the function-oriented groups forming thecontrolling system should be placed to the left of, or above, the function-orientedgroups that represent the controlled system. (See Figure 4.5.)

In a diagram with a topographical layout, the symbols should be grouped and placedto show the relative physical positions of the corresponding components.(See Figures 1.13 and 1.22.)

FIGURE 4.1 EXAMPLE OF FUNCTIONALLY RELATED COMPONENTS

FIGURE 4.2 EXAMPLE OF PARALLEL PATHS OF EQUAL IMPORTANCE

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FIGURE 4.3 EXAMPLE OF THE CIRCUIT REFERENCE SYSTEM

Horizontal connecting lines

Preferred signal flow

Vertical connecting lines

Non preferred signal flow (requires symbolsdesigned for signal flow from right)

FIGURE 4.4 EXAMPLES OF ARRANGEMENT OF CIRCUITS CONTAINING

BINARY LOGIC ELEMENTS

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FIGURE 4.5 EXAMPLE OF FUNCTIONAL GROUPING AND SIGNAL FLOW DIRECTIONS—

A CONTROL SYSTEM

4.4 LOCATION REFERENCE SYSTEMS

If it would otherwise be difficult to locate a symbol or an end of an interrupted connectingline in a diagram, the diagram shall incorporate a location reference system such as—

(a) a grid reference system according to Clause 2.9.2;

(b) a circuit reference system, wherein the branches of a circuit are identified bynumbers. (See Figure 4.3.)

(c) an item designation tabular reference system wherein, along one edge of thediagram, the item designations are repeated in line with the corresponding symbols.The item designations should be arranged in columns (or rows), one for each of themost frequently used types of parts (capacitors, resistors, relays, etc.), and one forall other types of parts. (See Figure 4.6.)

4.5 METHODS OF THE REPRESENTATION OF COMPONENTS AND CONNECTIONSIN DIAGRAMS

Functionally dependent parts of a component are represented as follows:

(a) Attached representation

A representation where the parts of a composite symbol are placed together.(See Figures 4.7 and 1.6.)

(b) Semi-attached representation

A representation where the symbol is extended with each part placed in the diagramto achieve a clear layout of the circuits, the parts being connected by a dashed linerepresenting a functional linkage. (See Figures 4.8 and 1.7.)

NOTE: This is usually used for components having a mechanical functional linkage.

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FIGURE 4.6 EXAMPLE OF THE TABULAR REFERENCE SYSTEM

(c) Detached representation

A representation where the symbol is separated into its parts with each part placedin the diagram to achieve a clear layout of the circuits, the parts being related bytheir item designations. (See Figures 4.9 and 1.8.)

NOTE: This is used for components having a functional linkage.

(d) Repeated representation

A representation where a complete symbol is shown in two or more places in thediagram, the identical item designation for each appearance indicating that thesymbols represent only one component. (See Figure 4.10.)

NOTE: This is usually for components having an electrical functional linkage, for example binary logic elementsrepresented by a symbol including a common control block or a common output block.

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No. Attached representation Description Comments

1 Relay May be shown in semi-

attached representation

(Figure 4.8) or in detached

representation (Figure 4.9)

2 Pushbutton

3 Circuit-breaker, operated

by hand or motor, with

trip-free mechanism, trip

coil, over-current and

over-load releases.

4 Transformer with three

windings

May be shown in detached

representation (Figure 4.9)

5 Optical coupling device

6 Multiplexer with storage,

quad 2-input

May be shown in repeated

representation

(Figure 4.10)

FIGURE 4.7 EXAMPLES OF SYMBOLS IN ATTACHED REPRESENTATION

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NOTE: It is not viable for all circuits to use this representation.

FIGURE 4.8 EXAMPLES OF SYMBOLS IN SEMI-ATTACHED REPRESENTATION —

THE COMPONENTS REPRESENTED ARE THE SAME AS IN EXAMPLES 1–3 OF FIGURE 4.7

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FIGURE 4.9 EXAMPLES OF SYMBOLS IN DETACHED REPRESENTATION —

THE COMPONENTS REPRESENTED ARE THE SAME AS IN EXAMPLES 1–5 IN FIGURE 4.7

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FIGURE 4.10 EXAMPLE OF REPEATED REPRESENTATION— MULTIPLEXER REPRESENTED IN

EXAMPLE 6 OF FIGURE 4.7

(e) Grouped representation

A representation where:

(i) The symbols for the parts are surrounded by an outline. (See Figure 4.11.)

(ii) The symbols for the parts (usually binary logic and analogue elements) areabutted. (See Figure 4.12.)

(f) Dispersed representation

A representation where the symbols for the parts are separated and placed in thediagram to achieve a clear layout of the circuits, the parts being related by the itemdesignations. (See Figure 4.13.)

(g) Multiline representation

A representation where each connection is represented by a line. (See Figure 4.14.)

(h) Single-line representation

A representation where two or more connections are represented by a single line.(See Figure 4.15.)

FIGURE 4.11 EXAMPLE OF GROUPED REPRESENTATION — PACKAGE OF TWO

ELECTROMECHANICAL RELAYS

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FIGURE 4.12 EXAMPLE OF GROUPED REPRESENTATION — PACKAGE OF FOUR

AND-ELEMENTS WITH NEGATED OUTPUT

FIGURE 4.13 EXAMPLE OF DISPERSED REPRESENTATION— THE COMPONENTS

REPRESENTED IN a) ARE THE SAME AS IN FIGURE 4.11, THOSE REPRESENTED IN b) ARE

THE SAME AS IN FIGURE 4.12

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FIGURE 4.14 EXAMPLE OF CONNECTIONS IN MULTILINE REPRESENTATION—

STAR-DELTA STARTER

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FIGURE 4.15 EXAMPLE OF CONNECTIONS IN SINGLE-LINE REPRESENTATION—

SAME STAR-DELTA STARTER AS IN FIGURE 4.14

4.6 SYMBOLS WITH A LARGE NUMBER OF TERMINALS

If the symbol for a device having a large number of terminals, for example, hundreds ofpins, is too large to be placed on a single sheet of a diagram, the following possibilitiesshould be considered:

(a) If the device has functionally independent parts, show the device using dispersedrepresentation, as described in Clause 4.5(f).

(b) If the device has functionally dependent parts, show the device using semi-attachedrepresentation, as described in Clause 4.5(b).

(c) If the device can be represented by an internal function diagram, replace the symbolwith a function diagram having symbols and (internal) connecting lines in appropriateplaces.

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(d) Simplify the symbol by indicating multiple, preferably related, terminals by a singleterminal symbol. Alternatively, the full details of a multiterminal input or output maybe explained in a separate table. (See Figures 4.16, 4.17 and 4.18.)

(e) If there is no alternative but to represent the device by a single symbol, break thesymbol outline into parts and use the rules for detached representation, (seeClause 4.5(c)). (See Figure 4.19.)

FIGURE 4.16 EXAMPLE OF BREAKING THE OUTLINE OF A SYMBOL WITH A LARGE

NUMBER OF TERMINALS

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FIGURE 4.17 EXAMPLE OF SIMPLIFIED REPRESENTATION OF CONNECTIONS TO A

COMPONENT — AND-GATE WITH NEGATED OUTPUT a) WITHOUT TERMINAL DESIGNATIONS,

b) WITH TERMINAL DESIGNATIONS, c) WITH TERMINAL DESIGNATIONS IN CONSECUTIVE

ORDER OF SEQUENCE

FIGURE 4.18 EXAMPLE OF THE USE OF THE METHODS DESCRIBED IN FIGURE 4.17

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FIGURE 4.19 EXAMPLE OF SIMPLIFYING A SYMBOL WITH A LARGE NUMBER OF TERMINALS

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4.7 UNUSED PARTS

In a circuit diagram or in supporting documents, unused, functionally dependent parts of acomponent, for example, unused contacts, windings and elements of an array, should beshown or referenced. Unused functionally independent parts of a component, for example,unused switches in a dual-in-line switch-package or unused gates in a package, may beshown or referenced.

4.8 DISTRIBUTED CONNECTIONS (WIRED-AND, WIRED-OR)

There are two basic methods in AS/NZS 1102 Part 112 for showing the distributed-ANDfunction and two basic methods for showing the distributed-OR function.

In each case of Figure 4.20, Method 1 uses one of the usual methods of showing a junctionwith the addition of a qualifying symbol to denote the logic function performed.

Method 2 replaces the junction with a rectangle containing the ‘&’ or ‘≥1’ qualifying symbol,

followed by the qualifying symbol ◊, indicating that the logic function is performed by adistributed connection instead of a separate element.

FIGURE 4.20 METHODS OF REPRESENTING DISTRIBUTED CONNECTIONS

Method 2 permits the use of qualifying symbols for negated inputs and negated outputs withpositive and negative logic, and for the logic polarity indicator with direct logic polarityindication. These are used with the rectangular symbol in the same manner that they wouldbe used if the logic were performed by discrete logic gates with one exception: all the inputsand the outputs shall show the same qualifying symbol since a distributed connection cannotperform logic negation or inversion.

With Method 1, there is no outline and therefore it is not possible to use input and outputqualifying symbols. Therefore, to understand the logic performed by the distributedconnection, it is necessary to consider the types of outputs that are connected together.

L-type open-circuit outputs (for example, NPN open collectors) connected together performeither active-high ANDing or active-low ORing. H-type open circuit outputs (for example,NPN open emitters) connected together perform either active-high ORing or active-lowANDing. (See Table 4.1.)

Table 4.1 assumes that the same negation symbols or logic polarity symbols can beappropriately used at the driving outputs and the driven inputs. Nevertheless, if it is notpossible to follow this recommended practice at all points in a diagram, the presence orabsence of negated output or active-low output qualifying symbols does not influence whichtype of logic AND or OR applies. In Figure 4.21 the AND and OR representations areequivalent.

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FIGURE 4.21 EXAMPLE OF DISTRIBUTED CONNECTIONS WITH NEGATED AND

NON-NEGATED OUTPUTS

The same principle applies for direct logic polarity indication, In Figure 4.22 the AND and theOR representations are equivalent.

FIGURE 4.22 EXAMPLE OF DISTRIBUTED CONNECTIONS WITH ACTIVE-HIGH AND

ACTIVE-LOW OUTPUTS

4.9 LAYOUTS OF COMMONLY USED FUNDAMENTAL CIRCUITS

4.9.1 General

Commonly used fundamental circuits should have a formalized pattern. Additionalcomponents should be arranged so that the basic pattern remains recognizable.

4.9.2 Terminations

Two-terminal passive networks should be represented with the terminals shown at the sameend. (See Figure 4.23.)

Four-terminal passive networks, such as filters, smoothing circuits, attenuators, and phase-shift networks, should be represented with the terminals shown at the corners of animaginary rectangle. (See Figure 4.24.)

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FIGURE 4.23 EXAMPLE OF A TWO-TERMINAL PASSIVE NETWORK

FIGURE 4.24 EXAMPLE OF A FOUR-TERMINAL PASSIVE NETWORK

4.9.3 Fundamental bridge circuits

Fundamental bridge circuits should be represented as in Figure 4.25.

FIGURE 4.25 EXAMPLES OF FUNDAMENTAL BRIDGES

4.9.4 RC-coupled amplifying stages

The symbols for the fundamental elements of RC-coupled amplifying stages should bearranged as shown in the following Figures:

(a) Common base (two alternatives). (See Figure 4.26.)

(b) Common emitter. (See Figure 4.27.)

(c) Common collector (emitter follower). (See Figure 4.28.)

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FIGURE 4.26 EXAMPLES OF AN RC-COUPLED AMPLIFYING STAGE WITH AN NPN

TRANSISTOR, COMMON BASE

FIGURE 4.27 EXAMPLE OF AN RC-COUPLED AMPLIFYING STAGE WITH AN NPN

TRANSISTOR, COMMON EMITTER

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FIGURE 4.28 EXAMPLE OF AN RC-COUPLED AMPLIFYING STAGE WITH AN NPN

TRANSISTOR, COMMON COLLECTOR

4.9.5 Fundamental bistable circuits

The symbols for the fundamental elements of elementary bistable circuits should bearranged as shown in Figure 4.29.

FIGURE 4.29 EXAMPLE OF A FUNDAMENTAL CIRCUIT, AN RS-LATCH CIRCUIT

4.10 SIMPLIFICATION TECHNIQUES

4.10.1 General

Simplifications may be used, for example to increase the amount of information shown oneach sheet or to reduce clutter by eliminating repetitive information. In general, anysimplification method may be used that does not impair the understanding of the drawing. Ifother simplication techniques than those shown are employed, they shall be explained onthe drawing or in the supporting documentation unless they are self-explanatory.

4.10.2 Multiple connections

Two or more identical branches of a circuit may be shown by representing one branch andusing symbol 103-02-09 (see Appendix D). (See Figure 4.30.)

The techniques of bundling and having identical symbols in a group may also be used asshown in Figure 4.31. The right-hand portion of eight circuits, identical except for the itemdesignations, is shown simplified.

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FIGURE 4.30 EXAMPLE OF MULTIPLE CONNECTIONS

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FIGURE 4.31 EXAMPLE OF EIGHT CIRCUITS, THE RIGHT-HAND PORTIONS

SHOWN SIMPLIFIED

4.10.3 Bundling

Multiple parallel connecting lines may be represented by one line (a connecting-line bundle)using one of the following methods:

(a) The parallel connecting lines are interrupted; a cross-line after a short spacerepresents the bundling. (See Figures 4.32, 4.33 and 4.34(a).)

(b) Each individual connecting line joins the bundle line sloping in the direction of theother end(s) of the individual line. (See Figures 4.34(b), 4.35 and 4.36.) Lines forminga junction with any of the lines in the bundle join the bundle without sloping. (SeeFigure 4.36.)

If the sequence of the connecting lines is the same but the order is not obvious, for examplewhen the bundle line is bent, as in Figure 4.33, the first connecting line shall be indicated ateach end, for example with a dot.

If the sequences at the ends are different, each connecting line shall be identified at eachend. (See Figures 4.34, 4.35 and 4.36.)

The number of connecting lines represented by a bundle line shall be indicated wherenecessary. Symbol 103-01-01 (Appendix D) provides two forms; Figure 4.37 shows anexample using 103-01-01 form 2.

4.10.4 Identical symbols in a group

A number of identical symbols in a group may be represented by a single symbol, providedwith a short oblique stroke and a figure indicating the number of symbol elementsrepresented by the single symbol element.

Another method, usable especially with symbols of rectangular shape, is to show therepresented number of symbol elements by a figure followed by a multiplication sign withinsquare brackets, for example [3×]. (See Figure 4.38.)

Note that multiple connections are distributed equally among identical elements.

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FIGURE 4.32 EXAMPLE OF BUNDLING, METHOD (a)

(See Clause 4.10.3)

FIGURE 4.33 EXAMPLE OF BUNDLING, METHOD (a), USING A DOT TO INDICATE THE FIRST

CONNECTING LINE

FIGURE 4.34 EXAMPLE OF BUNDLING WITH INDICATION OF INDIVIDUAL LINES,

METHODS (a) AND (b)

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FIGURE 4.35 EXAMPLE OF BUNDLING, METHOD (b), WITH LINES IDENTIFIED BY SIGNAL

DESIGNATIONS

FIGURE 4.36 EXAMPLE OF BUNDLING, METHOD (b), WITH LINES IDENTIFIED BY SIGNAL

DESIGNATIONS

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FIGURE 4.37 EXAMPLE OF THE USE OF SINGLE-LINE REPRESENTATION WITH THE NUMBER

OF CONNECTING LINES INDICATED

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FIGURE 4.38 EXAMPLES OF SIMPLIFIED REPRESENTATION OF COMPONENTS

AND CONNECTIONS

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4.11 NOTES ON DIAGRAMS

4.11.1 Inset diagrams

In detached representation, the referencing from the actuating or affecting parts to the otherparts may be carried out as inset diagrams or inset tables, adjacent to the actuating oraffecting part. If this location is not practical, they may be located elsewhere in the diagramor in a separate document. In the latter case a reference to that document shall be added tothe symbol for the actuating or affecting part.

Examples: Figure 4.39 gives an example of the use of inset diagrams. In Figure 4.40 theinset diagrams are replaced with inset tables.

FIGURE 4.39 EXAMPLE OF THE USE OF INSET DIAGRAMS

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FIGURE 4.40 EXAMPLE OF THE USE OF INSET TABLES

4.11.2 Functional description—A switch

For manually operated control switches with a complex function, a graph shall be included inthe diagram, if necessary, to understand the function. (See Figure 4.41.)

FIGURE 4.41 EXAMPLE OF A GRAPH FOR DESCRIBING THE FUNCTIONS OF A

MANUALLY OPERATED CONTROL SWITCH

For pilot switches, the diagram shall contain a description of the operation, adjacent to thesymbol. This description may consist of—

(a) a graph, prepared in accordance with the examples in Figure 4.42 and in the left-handcolumn of Table 4.1. In these examples, the indication ‘O’ on the Y-axis stands for‘contact open’ and ‘1’ for ‘contact closed’. If no confusion is likely, these indicationsmay be omitted;

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(b) a symbol for the actuating device. For cam-operated or similarly operated devices, thesymbol shown in the third column of Table 4.1 may be used; or

(c) a note, designation or table. (See Figure 4.43.)

FIGURE 4.42 EXAMPLE OF A GRAPH FOR DESCRIBING THE FUNCTIONS OF A PILOT SWITCH

FOR SPEED MONITORING

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TABLE 4.1

EXAMPLES OF GRAPHS AND CAM SYMBOLS TO DESCRIBE CONTACT FUNCTIONS

No.Description in circuit diagram

ExplanationGraph symbol Cam symbol

1 Contact is closed at temperatures equal

to or exceeding 15°C

2 Contact closes at 35°C when the

temperature increases and then opens

when the temperature decreases to 25°C

(see Note)

3 Contact is closed at 0 m/s and opens at

5.2 m/s when the speed increases and

closes at 5 m/s when the speed

decreases (See Note)

4 Contact is closed between 60° and 180°

and between 240° and 330°

5 Contact is open between position X and

position Y

6 Contact is closed only at position X

7 Contact is closed in end position X and

beyond

NOTE: If the return value is of less interest, it may be put within brackets or omitted.

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FIGURE 4.43 EXAMPLE OF A NOTE FOR DESCRIBING THE FUNCTIONS OF A PILOT SWITCH

FOR SPEED MONITORING

4.12 ORIENTATION OF CONTACT SYMBOLS

Contact symbols should be oriented so that the imaginary direction of movement isconsistent. For example, movement upwards with horizontal connecting lines or to the rightwith vertical connecting lines when the component is actuated. This is especially important ifthe symbol for the complete component contains symbols for a mechanical latch, blockingdevice, delay device or similar. However, when using detached representation in circuitswith complicated contact arrangements but without, for example, mechanical latches, thecontact symbol orientation may be changed if this results in a clearer layout of the diagramwith a minimum of crossings.

4.13 REPRESENTATION OF SUPPLY CIRCUITS

Connections that satisfy power or voltage supply requirements of devices shall be indicatedin circuit diagrams and may be indicated in other diagrams. The connections may be showngraphically, or may be specified in a table or a note. (See Figure 4.44.)

FIGURE 4.44 EXAMPLES OF THE REPRESENTATION OF CONNECTIONS FOR POWER

OR VOLTAGE SUPPLY

The supply lines should be shown at opposite sides of the circuit branches (seeFigure 4.45), or grouped together to one side of, above or below, the circuit (seeFigure 4.46). Supply lines may also be interrupted to aid the layout of the diagram, providedthe requirements in Clause 4.15 are met. (See Figure 4.47.)

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FIGURE 4.45 EXAMPLE SHOWING SUPPLY REPRESENTED BY LINES WITH POLARITY

INDICATIONS

FIGURE 4.46 EXAMPLE OF GROUPED SUPPLY LINES

FIGURE 4.47 EXAMPLE OF A FUNCTIONAL UNIT WITH POWER SUPPLY

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Supply lines to a block symbol may be drawn at right angles to the signal flow.(See Figure 4.48.)

FIGURE 4.48 EXAMPLE OF SUPPLY LINES TO A BLOCK SYMBOL

These methods may also be used inside a functional or constructional unit. (SeeFigure 4.47.)

A component may be represented as two or more symbols, one of them showing only thesupply connections. (See Figure 4.49.)

FIGURE 4.49 EXAMPLE OF A COMPONENT WITH ONE PART FOR THE SUPPLY

4.14 REPRESENTATION OF COMBINED ELECTRICAL AND NON-ELECTRICALCIRCUITS

Relations between non-electrical and electrical functions shall be clearly indicated.(See Figure 4.50.) The dot at one end of the arrows correlates the direction of rotation of themotor and the corresponding direction of motion of the sliding contact of the resistor.

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FIGURE 4.50 EXAMPLE OF MECHANICAL FUNCTIONS RELATED TO ELECTRICAL

FUNCTIONS

4.15 INTERRUPTED LINES

If a connecting line would cross a large part or a congested area on a diagram, theconnecting line may be interrupted. In this case, and also when a connecting line isinterrupted on one sheet and continues on another, the ends of the interrupted lines shall bemutually referenced.

The ends of the interrupted line should be drawn so that they can be easily recognized.

The reference shall consist of one or more of the following:

(a) Signal designation or another identification.

(b) Symbol for connection to earth, frame or any other common point.

(c) Inset tables.

(d) Other unambiguous means.

If required for clarity, location references on the diagram (e.g. grid references) of the relatedends should be provided.

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CHAPTER 5

INTERCONNECTION DIAGRAMS AND TABLES

5.1 GENERAL

Interconnection diagrams and tables provide information on the external electricalconnections between units of equipment and may be used as an aid in the preparation of thewiring harnesses and for maintenance purposes.

Information on the internal connections in units is not normally included, but if it is,references to the appropriate circuit or wiring diagrams should be provided.

The diagrams may employ single-line or multiline representation and may be combined withor replaced by tables, provided that clarity is maintained. Tables are recommended wherethe number of interconnections is large.

5.2 INTERCONNECTION DIAGRAMS

5.2.1 Layout

Interconnection diagrams employ straight lines and simple outlines, i.e. squares, circles orrectangles, to depict equipment units. The connections between the units are symbolized bylines which may represent individual wires or complete cables. The diagrams should bearranged so that the lines can be drawn in a simple and logical manner between the variouspoints of termination.

Views should be shown as though all connections were in one plane. Where practicable, thesequence and arrangement of the equipment symbols on the diagram should depict thephysical arrangement of the installation. A location diagram should complete interconnectioninformation if the relative location of such items as terminals or connectors is not clear.

Figure 5.1 is an example of a simple interconnection diagram.

NOTE: The cable symbol is identified by an item designation symbol, e.g. W2, and a notation indicating the

number of conductors and their cross-sectional area in square millimetres, e.g. 3 × 1.5.

FIGURE 5.1 SIMPLE INTERCONNECTION DIAGRAM

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5.2.2 Identification

5.2.2.1 Units of equipment

The outline representing each item should be suitably identified, e.g. by a functional title oritem designation, as necessary.

5.2.2.2 Connectors

The symbol for each connector should be identified, e.g. by item designation. Suchidentification is not required if the connector forms part of a cable assembly separatelydesignated in the interconnection information, or if it is of a type covered by an explanatorynote.

Cabling information may be shown on the diagrams together with identification of connectingassemblies, adaptors, cable clamps, etc., and any special assembly instructions which arerequired.

5.2.2.3 Terminals and connector contacts

These should be identified by at least one of the following methods:

(a) Existing markings shown on the drawing.

(b) Designation in associated documentation.

(c) Arbitrary designation explained in the interconnection information.

5.2.2.4 Conductors

Where considered necessary, the line representing each conductor (either individual or in acable) should be identified by at least one of the following methods:

(a) Existing markings or colour coding on the conductor shown on the drawing.

(b) A code assigned on an overall system basis as explained on the diagram or insupporting documentation.

Supplementary information such as conductor function, size, length, screening or voltagerating may be included.

5.2.2.5 Jumper wires

These wires are generally single-insulated conductors.

The individual wires, which are normally terminated on terminal or tag blocks, are used tointerconnect circuit functions within the same rack or to other racks within the equipmentroom. (See Figure 5.2.)

This connection method readily allows jumper terminations to be altered as required, makingthe system completely flexible.

5.3 TYPES OF DIAGRAMS

5.3.1 Individual conductor representation

Each individual conductor between equipment items should, where possible, be representedby a separate line. (See Figure 5.3.)

Apart from small gaps necessary to accommodate identification or supplementaryinformation, the lines may be drawn in full between the appropriate terminations.(See Figure 5.4.)

To simplify a diagram, a group of lines may be replaced by a single line for some part of theirlength, provided that the ends are suitably designated. (See Figure 5.5.)

This method may be extended by branching the single line where groups of lines havedifferent destinations. In such cases, information on the other end termination may beusefully shown at both ends of every line representing an individual connection.(See Figure 5.6.)

Repeated information at the ends can generally be omitted. (See Figure 5.7.)

Alternatively, it is permissible to omit the individual lines for most of their length, providedthat corresponding ends are suitably identified and information on remote end destination isincluded. (See Figure 5.8.)

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FIGURE 5.2 JUMPERING

FIGURE 5.3 SEPARATE REPRESENTATION OF CONDUCTORS

FIGURE 5.4 IDENTIFICATION OF CONDUCTORS

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FIGURE 5.5 SINGLE-LINE REPRESENTATION

FIGURE 5.6 IDENTIFICATION OF CONDUCTORS WITH DIFFERENT DESTINATIONS

FIGURE 5.7 ALTERNATIVE METHOD OF IDENTIFICATION OF CONDUCTORS

WITH DIFFERENT DESTINATIONS

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FIGURE 5.8 IDENTIFICATION OF REMOTE DESTINATIONS

5.3.2 Multiconductor representation

Each multiconductor assembly (cable, conductors in sheath or similar) connecting thevarious items of equipment should be represented by a single line. (See Figure 5.9.)

Lines representing multiconductor assemblies may be omitted for part of their length,provided that the residual ends are identified and opposite end destinations are given. Forexample, in Figure 5.8, Panel F may be on a different drawing from Panel D or Panel E.

Where panels are wired to other panels on different drawings, the relevant drawing numbersshould be quoted.

5.4 INTERCONNECTION TABLES

5.4.1 General

The information given by interconnection diagrams can be conveniently given by listing intabular or matrix form. Usually, each line of information relates to an individualconnection. The information relating to all connections to a given unit may be presented onsequential lines of a table. See Table 5.1 for an example. Alternatively, the information maybe listed in circuit order.

The details of such arrangements will depend on the circumstances of each case. The basicdata shall include information regarding the connection points and the conductor. Manysatisfactory variations are possible; that shown in Table 5.1 is an example only.

Tables may be supplemented with equipment layout information showing the following:

(a) The relative location of all portions of the equipment.

(b) The terminal arrangement and identification of unmarked terminals. The data shouldshow a wiring side view of the terminal arrangement. A left-to-right and top-to-bottomsequence assignment of terminal identification is recommended.

(c) Any special wiring arrangements which cannot be conveyed by tabular informationalone.

(d) The paths of the wiring where such paths are not readily determined.

Typical column headings for this supplementary information could include thefollowing:

(i) Unit designation.

(ii) Plug/socket/terminal number.

(iii) Pin/terminal designation.

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(iv) Cable number.

(v) Wire number and/or colour.

(vi) Cross-sectional area/stranding.

(vii) Twisted with wire number.

(viii) Screened singly/with wire number.

(ix) Pin/terminal designation.

(x) Socket/plug/terminal number.

(xi) Unit designation.

5.4.2 Example of interconnection table

This example is typical of the way in which the information given in a diagram may bepresented. In this case, Table 5.1 gives similar information to Figure 5.7.

FIGURE 5.9 REPRESENTATION OF MULTICONDUCTOR ASSEMBLIES

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TABLE 5.1

ALTERNATIVE PRESENTATION OF INTERCONNECTION SHOWN IN FIGURE 5.7

Wire number Size, mm2 Colour From To Notes

75 1.5 RD 1 × 1: A 2 × 1: A

76 1.5 BK 1 × 1: B 2 × 1: B

77 2.5 RD 1 × 1: C 2 × 2: A

78 2.5 WH 1 × 1: D 2 × 2: B

79 2.5 BU 1 × 1: E 2 × 2: C

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CHAPTER 6

UNIT WIRING DIAGRAMS AND TABLES

6.1 GENERAL

Unit wiring diagrams and tables provide information on the internal electrical connections ofa unit or assembly of units.

Information on the external connections between units is not usually included, butreferences to the appropriate interconnection diagrams or tables may be provided.

Unit wiring diagrams and tables may supplement one another, and both may also containinformation from other documents, such as working drawings, circuit diagrams or parts lists.

6.2 ITEM DESIGNATION AND MARKING

6.2.1 Item designation—general

Item designations appearing on the wiring diagram or table should be the same as those onthe corresponding circuit diagram and associated documentation.

6.2.2 Identification of wiring

Cables, cores or conductors may be identified by a simple numerical designation. Where it isconsidered necessary, further identification should be given by at least one of the followingmethods:

(a) Showing (on the drawing) markings or colour codings that exist on the wiring.

(b) Explaining (on the drawing or in supporting documentation) a code assigned on anoverall system basis.

(c) Including (on the drawing) supplementary information such as conductor function,size, length, screening and voltage rating.

6.2.3 Terminals

Each point of termination should be identified by at least one of the following:

(a) Marking appearing on the actual item.

(b) Designation appearing in associated documentation.

(c) Arbitrary designation explained in the wiring information.

6.3 LAYOUT

Unit wiring diagrams should usually be drawn in approximate topographical representation.

6.4 VIEW OF EQUIPMENT

The view or views of equipment that are required for a unit wiring diagram are those whichwill most clearly show the terminals or wiring sides of the component devices or parts asthey are mounted in the equipment. In most instances, one view as seen from the wiring sideof the items should be sufficient. This view should generally correspond to the view of theitems as seen during wiring. More than one view may be required where the equipment iswired from both front and rear. In such a case, the diagram should clearly identify which viewof the equipment is shown. Component devices or parts with more than one level ofterminals may also require more than one view.

6.5 COMPONENTS, DEVICES AND PARTS

Unit wiring diagrams employ straight lines and simple outlines, e.g. squares, circles orrectangles, to depict equipment items. Sometimes, graphical symbols may be used.Mechanical details, such as the fastening for an item, should only be shown if this helps inthe understanding of the diagram.

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If items are located above each other at several levels, these items may be shown in thediagrams as rotated, turned or moved in such a way that the terminals may be seen by thereader of the diagram. The method used should be appropriately indicated. (See Figures 6.1and 6.2.)

6.6 TERMINALS

Terminals may be represented by graphical symbols. In some cases, it may be sufficient toonly show the terminal designation on the outline depicting a device.

If a convention is used to distinguish between detachable and non-detachable connections,it should be shown or referenced on the diagram.

6.7 WIRING

6.7.1 General

The unit wiring diagram may show technical data for the conductors, such as type andcross-sectional area.

A unit wiring diagram should show where wiring is to be twisted, shielded or separated fromother conductors. In the representation of a shielded cable, the diagram should showwhether the shield is to be isolated or connected and, in the latter case, a clear distinctionshould be made between the termination of the conductor and the shield.

NOTE: Figure 6.3 shows wires 44 and 45 and wires 46 and 47 twisted.

NOTE: The long line on the right indicates the axis of rotation.

FIGURE 6.1 A SOLDERING TERMINAL STRIP, THE END OF WHICH IS

VIEWED IN THE EQUIPMENT ROTATED TO THE LEFT THROUGH 90 DEGREES

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FIGURE 6.2 EXAMPLE OF A UNIT WIRING DIAGRAM USING SINGLE-LINE REPRESENTATION

6.7.2 Individual line representation

In simple cases, the connections between items may be depicted by individual lines.(See Figure 6.3.)

6.7.3 Grouped wiring

Grouped wiring may be represented by a common line. If a unit contains several wiringgroups, these should be properly distinguished from one another. (See Figure 6.2.)

To minimize the possibility of confusion, the number and colour attributed to an individualconnection should be on the same side of the connection, and associated as closely aspossible. Where the number appears directly over a terminal, the colour code should appeareither at the top or to the left of the connection.

6.7.4 Interrupted lines

Interrupted line technique may be used to clarify the diagram. Provision should be made forthe association of the interrupted lines. In this technique, the marking system used for theconnections designates the destination, and may be independent of that used for theterminals. In Figure 6.4, the destination shows both terminal number and device number ordesignation.

6.7.5 Reference line system

One alternative method for the display of information given in Figure 6.4 is the reference linesystem. An example, which presents the same information as Figures 6.2, 6.3 and 6.4, isgiven in Figure 6.5. Such a diagram, used in conjunction with a layout diagram, is equallysuitable for manufacturing and maintenance purposes.

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FIGURE 6.3 EXAMPLE OF A SIMPLE UNIT WIRING DIAGRAM USING

INDIVIDUAL LINE REPRESENTATION

FIGURE 6.4 EXAMPLE OF A UNIT WIRING DIAGRAM USING INTERRUPTED LINE TECHNIQUE

AND WIRE DESTINATION REPRESENTATION

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FIGURE 6.5 EXAMPLE OF A SIMPLE UNIT WIRING DIAGRAM USING THE

REFERENCE LINE SYSTEM

6.8 UNIT WIRING TABLES

6.8.1 General

The information given by unit wiring diagrams can be conveniently given by listing in tabularor matrix form. Usually each line of information relates to an individual connection. Theinformation relating to all connections to a given unit may be listed in circuit order. The basicdata shall include information regarding the connection points and the cable, core orconductor.

Tables may be supplemented with a diagram to show equipment layout information, such asthe relative location of items, the terminal arrangement and identification of unmarkedterminals, and any special wiring arrangements.

NOTE: A left-to-right and top-to-bottom sequence assignment of terminal identification is recommended.

6.8.2 Examples of unit wiring tables

The examples are typical of the way in which the information given in a diagram may bepresented. In this case, Table 6.1 gives similar information to Figure 6.3 for items 13, 14,and 15, and should be regarded as an alternative to this diagram.

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SAA/SNZ HB3 :1996 100

TABLE 6.1

UNIT WIRING SCHEDULE FOR ITEMS 13, 14 AND 15 FROM FIGURE 6.3

Connection number From Item:Terminal To Item:Terminal Remarks

40 13:1 12:6

— 13:1 R1

— 13:2 R1

52 13:3 13:4

41 14:A X1:5

42 14:B X1:6

43 14:C 16:11

35 14:C 11:5

44 15:1 X1:7 Twisted pair

45 15:2 X1:8

46 15:3 X1:9 Twisted pair

47 15:4 X1:10

33 15:5 11:3

48 15:6 16:12

6.9 EXAMPLES OF WIRING DIAGRAMS

Figures 6.6 to 6.9 and Table 6.2 are examples of the application of the variousrecommendations given in Clauses 6.2 to 6.8. They are intended to only show methods ofrepresentation and are not meant as recommendations concerning the equipment.

The examples represent equipment of different kinds. It is not, however, the intention toprescribe that the method of representation, chosen here for a certain kind of equipment, bespecific for equipment of this kind.

(a) Figure 6.6—single-line representation is used.

(b) Figure 6.7—shows the same equipment as Figure 6.6, using a tabular method.

(c) Figure 6.8—shows the reference line technique equivalent to Figure 6.6. Note alsothat the wiring loom or ducts to be used are indicated by the symbol:

A

(d) Figure 6.9—shows the interrupted line technique equivalent to Figure 6.6.

(e) Table 6.2—the tabular approach is used to produce a wiring schedule with the aid of acomputer.

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101 SAA/SNZ HB3 :1996

FIGURE 6.6 WIRING DIAGRAM, CONTROL PANEL HV POWER SWITCHGEAR

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FIGURE 6.7 TABULAR EQUIVALENT OF FIGURE 6.6

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FIGURE 6.8 REFERENCE LINE EQUIVALENT OF FIGURE 6.6

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FIGURE 6.9 INTERRUPTED LINE EQUIVALENT OF FIGURE 6.6

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TABLE 6.2

WIRING SCHEDULE PRESENTED BY COMPUTER IN TABULAR FORM

THE WIRING LEGEND IS AS SET OUT BELOW:

TYPE DESCRIPTION

A TCW* 2 X 0.7 MM

B RED 16/0.20 MM PVC INSULATED

C ORANGE– BLUE 16/0.20 MM PVC INSULATED

D BROWN 16/0.20 MM PVC INSULATED

E BLACK 16/0.20 MM PVC INSULATED

G RED –BLACK 16/0.20 MM PVC INSULATED

H ORANGE 16/0.20 MM PVC INSULATED

J BLUE 16/0.20 MM PVC INSULATED

K BLUE –BLACK 24/0.20 MM PVC INSULATED

L BLACK 24/0.20 MM PVC INSULATED

M GREEN– RED 24/0.20 MM PVC INSULATED

N BLACK –GREEN 16/0.20 MM PVC INSULATED

P GREY– RED 16/0.20 MM PVC INSULATED

WHERE NO TYPE IS SHOWN, USE 16/0.20 MM PVC INSULATED .

THE FOLLOWING CONNECTIONS DO NOT APPEAR IN THE WIRING SCHEDULE, BUT MUST ALSO

BE WIRED IN:

K1:5 TO K1:6 TYPE A

K3:10 TO K3:11 TYPE A

K4:2 TO K4:3 TYPE A

K4:3 TO K4:5 TYPE A

K5:1 TO V2:1 TYPE A

K5:2 TO V1:2 TYPE A

K5:4 TO V1:1 TYPE A

K5:4 TO V2:2 TYPE A

DRG. NO:

SHEET 1

INITIALS

DATECHANGE

MOD.

NO.TITLE

(continued )

* Tinned copper wire.

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TABLE 6.2 (continued)

LINK FROM TO TYPE FUNCTION

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

K3:5

K3:4

X1:5

K3:11

K8:1

K3:3

K2:4

X2:6

X2:5

X2:8

X2:7

K2:6

K2:2

K3:14

K2:1

K1:2

K3:7

K3:6

K3:1

K1:3

K2:5

K1:6

K1:4

K3:8

K4:7

K4:9

K4:12

K4:13

X2:3

K7:5

K1:1

X1:8

X1:7

X1:2

K7:4

K8:2

K7:1

K7:2

K2:3

K7:3

X2:1

K6:2

K6:1

K3:15

K3:13

K4:1

K5:1

X1:3

X2:2

X2:4

X1:1

K4:4

X1:6

K4:6

K3:12

K3:10

X1:4

K5:2

K5:7

K5:6

K5:3

K7:6

K6:3

K8:1

K5:5

K4:11

K4:8

K3:2

C

M

M

B

E

D

E

E

H

B

D

C

H

J

J

M

M

P

J

G

G

M

H

N

M

D

C

K

J

J

B

B

E

B

DRG. NO:

SHEET 2

INITIALS

DATECHANGE

MOD.

NO.TITLE

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107 SAA/SNZ HB3 :1996

CHAPTER 7

OVERVIEW DIAGRAMS

7.1 GENERAL

An overview diagram shall provide an overview of any kind of system, subsystem,installation, equipment, software or similar; for example, a radio receiver or a power station.It shall show the main relationships among the main functions and components.

This type of diagram can serve as an introduction for education, training, operating andmaintenance purposes.

NOTE: An overview diagram can serve as the basis for further design work, for example, for thepreparation of more detailed diagrams such as function diagrams and circuit diagrams.

7.2 LAYOUT

An overview diagram should be presented in a functional layout (see Figure 7.1). Locationinformation may be added. (See Figure 7.2.)

If location information is important to understanding the function, as in a network map, atopographical layout may be used. (See Figure 1.13.)

Overview diagrams may be prepared at different levels of the function-oriented structurewith the higher levels depicting the overall systems, and the lower levels depicting thesubsystems. (See Figures 7.3 and 7.4.)

The symbols representing the items shall be placed in the diagram in such a manner thatclear and recognizable flowpaths for information, control, energy and material aredistinguished.

An overview diagram at a certain level should contain references to documents describingthe lower levels. Each symbol, including the rectangles, shall be assigned an itemdesignation, where necessary. (See Figure 7.5.)

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FIGURE 7.1 EXAMPLE OF THE RECOMMENDED LAYOUT PRINCIPLE. NO ITEM DESIGNATIONS ARE SHOWN AS THE FIGURE IS INTENDED

TO SHOW THE LAYOUT PRINCIPLE ONLY

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FIGURE 7.2 EXAMPLE OF AN OVERVIEW DIAGRAM WITH LOCATION INFORMATION —

A HIGH-VOLTAGE SWITCHGEAR ASSEMBLY

FIGURE 7.3 EXAMPLE OF AN OVERVIEW DIAGRAM — A STEELWORKS

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FIGURE 7.4 EXAMPLE OF AN OVERVIEW DIAGRAM — THE ELECTRIC POWER DISTRIBUTION

SYSTEM =E1 IN FIGURE 7.3

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NOTE: The asterisk represents the proper item designation for the pump. Item designations for non-electrical

devices have not been dealt with in any International, Australian or New Zealand Standard.

FIGURE 7.5 EXAMPLE OF AN OVERVIEW DIAGRAM — THE COOLING-WATER SUPPLY

SYSTEM = W1 IN FIGURE 7.3

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7.3 OVERVIEW DIAGRAMS FOR CONTROL SYSTEMS FOR NON-ELECTRICALPROCESSES

An overview diagram for a control system for a non-electrical process shall be based on aflow diagram for that process. For example, Figure 7.6 shows a process flow diagram usingsymbols for measurement and control as specified in AS 1101.6, Graphical symbols forgeneral engineering, Part 6: Process measurement control functions and instrumentation.Figure 4.16 shows an overview diagram in which the measurement and control functions ofthe control system in Figure 7.6 are implemented by electrical means.

NOTE: AS 1101.6 is a source document which is not dealt with in this Handbook.

FIGURE 7.6 PART OF A PROCESS FLOW DIAGRAM —HEATING EQUIPMENT.

THE CONTROL FUNCTIONS ARE REPRESENTED IN ACCORDANCE WITH AS 1101.6

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CHAPTER 8

PRINCIPLES OF ORTHOGRAPHIC DRAWINGS

8.1 GENERAL

Electrical drafting officers should be aware of the principles behind basic orthographicdrawing techniques. More complex drawings such as those having auxiliary views are notdiscussed here. The following is derived from AS 1100.101, Technical drawingPart 101: General principles.

8.2 IDENTIFICATION

Features, cutting planes, sectional views, sections and special views should be identified byletters of the alphabet according to the following rules:

(a) Letters I, O, and Q shall not be used.

(b) When the other 23 letters have been exhausted, combinations of 2 letters shall beused, e.g. AA, AB, AC.

(c) Letters or letter combinations shall be used only once on any drawing, irrespective ofthe purpose; e.g. if ‘A’ is used to designate a view, it shall not be used on a feature,cutting plane, sectional view or section.

(d) Identifying letters or letter combinations for cutting planes shall be applied at each endof such planes, and in the corresponding notes for sectional views and sections, thesame identifying letters or letter combinations shall be used separated by a hyphen,e.g. SECTION A-A, SECTION B-B, SECTION AB-AB.

Views shall be designated as shown in Figure 8.1.

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View in direction A is designated: FRONT VIEWView in direction B is designated: TOP VIEWView in direction C is designated: LEFT SIDE VIEWView in direction D is designated: RIGHT SIDE VIEWView in direction E is designated: BOTTOM VIEWView in direction F is designated: REAR VIEW

FIGURE 8.1 DESIGNATION OF VIEWS

8.2.1 Views

(a) Top view (plan) The horizontal section or projection of any object, such as a building,or the projection on a horizontal plane of a site, building or component, viewed fromabove at right angles to the plane of section or projection.

(b) Side, front and rear view (elevation) The projection on a vertical plane of any object,such as a building or component viewed at right angles to the plane of projection.

8.3 TYPES OF PROJECTION

A drawing of a component, assembly, structure, or part thereof shall be drawn using one ormore of the projection methods shown in Table 8.1.

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TABLE 8.1

METHODS OF PROJECTION

Distinctive featureProjection type

Application ReferenceGeneric Particular

Parallel lines of sight Orthogonal Third angle

(preferred) First angle

Two-dimensional

multiview drawings

This chapter

Axonometric Isometric, Dimetric

Trimetric Three-dimensional

single-view

‘pictorial drawings’

Chapter 9 (Isometric

only) or see

AS 1100.101

Oblique Cavalier, Cabinet

General

See AS 1100.101

Converging lines of

sight

Perspective One-point (parallel)

Two-point (angular)

Three-point (oblique)

8.4 ORTHOGONAL PROJECTION

8.4.1 Terminology

Orthogonal projection is the projection of an object in which the line of sight is perpendicularto the plane of projection. Figure 8.2 illustrates the derivation of the terms ‘First AngleProjection’ and ‘Third Angle Projection’, as applied to orthogonal projection.

8.4.2 General

Third angle projection is the formation of an image of a view upon a plane of projectionplaced between the object and the observer. First angle projection places the objectbetween the observer and the plane of projection.

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FIGURE 8.2 ORTHOGONAL PROJECTION

8.4.3 Methods

The two methods of orthogonal projection in use, known as ‘third angle and first angle’, areas follows:

(a) Third angle projection Each view is placed so that it represents the side of the objectnear to it in the adjacent view (see Figure 8.3).

(b) First angle projection Each view is placed so that it represents the side of the objectremote from it in the adjacent view (see Figure 8.4).

The third angle method of projection is preferred.

All drawings in this Handbook are third angle unless otherwise stated.

The drawings shall be marked to indicate the method of projection i.e. third angle or firstangle projection. The directions in which the views are taken should be clearly indicated.

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FIGURE 8.3 EXAMPLE OF THIRD ANGLE PROJECTION WITH PROJECTION SYMBOL

FIGURE 8.4 EXAMPLE OF FIRST ANGLE PROJECTION WITH PROJECTION SYMBOL

8.4.4 Selection of views

(a) Principle of selection

Views shall be selected according to the following principles:

(i) To reduce the number of views required to fully delineate the information to bespecified.

(ii) To avoid the need for hidden outlines.

(iii) To avoid unnecessary repetition of detail.

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(b) Disposition and number of views The normal disposition of views in third angleprojections is shown in Figure 8.3 and that in first angle projection is shown inFigure 8.4. The number of views drawn shall be sufficient to portray the shape of theobject without possibility of misinterpretation. For many objects three views aresufficient. Any three adjacent views may be used.

NOTE: The views of Figures 8.3 and 8.4 do not necessarily define completely all features of an object. Fulldefinition may require the application of other following clauses, the use of notes and sometimes, the use ofsections.

Some objects may, however, be completely represented by less than three views where theinformation, which would have been given by the omitted views, is supplied by notes or othermeans. For example, some objects may be represented adequately even by one view if thenecessary dimensions are suitably indicated (see Figure 8.5).

FIGURE 8.5 SINGLE-VIEW DRAWINGS SUITABLY DIMENSIONED

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119 SAA/SNZ HB3 :1996

CHAPTER 9

PICTORIAL DRAWINGS

9.1 AXONOMETRIC PROJECTION

9.1.1 Terminology

Axonometric projection is the projection of an object in which the lines of sight areperpendicular to the plane of projection and where the object is orientated so that its threeprincipal axes are all inclined to the plane of projection. (See Figure 9.1.)

9.1.2 Methods

There are three methods of axonometric projection as follows:

(a) Isometric Where the three angles between the projections of the three principal axesof the object on the plane of projection form equal angles of 120°.

(b) Dimetric Where two of the angles between the projections of the three principal axesof the object on the plane of projection form equal angles and the third angle isdifferent.

(c) Trimetric Where the angles between the projections of the three principal axes of theobject on the plane of projection form unequal angles.

Isometric projection is recommended for depicting objects having characteristic features inall directions; dimetric and trimetric projections are recommended for depicting objectshaving characteristic features in two directions.

In this Handbook, only isometric drawings, as an example of one pictorial drawing technique,are described. Table 8.1 provides references to other methods of projection.

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FIGURE 9.1 AXONOMETRIC PROJECTION

9.2 CHOICE OF AXES FOR ISOMETRIC DRAWINGS

9.2.1 General

The axes are placed at 120°. By convention the projection of one of the principal axes of theobject is selected as a vertical axis.

9.2.2 Examples and guidelines

Figure 9.2 illustrates a typical isometric drawing of an object.

Lengths parallel to the principal axes shall be drawn in true length to any selected scale, i.e.the ratio of equal lengths on the axes shall be—

x:y:z = 1:1:1

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NOTE: All axes are drawn at full scale. The resulting distortion is tolerated.

FIGURE 9.2 EXAMPLE OF AN ISOMETRIC DRAWING

9.3 ISOMETRIC PROJECTION — ADDITIONAL INFORMATION

9.3.1 Drafting aids

The following drafting aids give assistance to drafters in the preparation of isometricdrawings:

(a) Special paper ruled in three directions at 120° to each other.

(b) Templates with a wide range of ellipses to represent circles.

(c) CAD software may contain isometric axes and subsets of ellipses to represent circles.

9.3.2 Representation of circles

A method of construction of approximations to ellipses is illustrated in Figure 9.3.

It should be noted that the major axis of an ellipse (e.g. part of line EG in Figure 9.3) in aprincipal plane is perpendicular to the third principal axis.

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1 Locate centre O by centre-lines COA and BOD. OA = OB = OC = OD = radius of circle.

2 Through B and D draw EBF and GDH parallel to COA. Through A and C draw EAH and FCG parallel to BOD.

3 Locate points J and K on GOE such that GK = EJ = OA.

4 With centre H and radius R1 (= HB) draw arc between HJ produced at L and HK produced at M. Similarly withcentre F.

5 With centres J and K and radius R2 (= HB - HJ) complete the figure.

FIGURE 9.3 CONSTRUCTION OF APPROXIMATE ELLIPSES REPRESENTINGCIRCLES IN ISOMETRIC DRAWING

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CHAPTER 10

DRAWING GRAPHS

These notes are intentionally brief as there is no Australian/New Zealand Standardspecifically detailing graph or chart representation. For a fuller explanation of this type ofdrawing, the reader is referred to the Engineering drawing handbook, published byStandards Australia as SAA HB7 and the Institution of Engineers Australia as IEAustNOE/93/01.

Graphical drawings are pictorial representations of data. They are used for design purposesand for provision of visual information.

The accuracy of the pictorial representation will depend upon the required resolution and theintended use of the data.

Graphical drawings will usually consist of two orthogonal axes, on which may besuperimposed any number of types of data which are to be represented. It is incumbentupon a drafting officer to provide graphical information in a clear and concise manner, whichmay result in the production of families of graphs if there are many types of data items to begraphed.

In some instances, there is the need to provide graphical information of three mutuallydependent quantities. This could be carried out by using isometric drawing techniques asdescribed in Chapter 9. Any graphical information which is ‘behind’ (in the visual sense) mayeither be hidden or displayed depending upon the application of the drawing. SeeFigure 10.1 as an example.

Other graphical drawings include polar diagrams as used in antenna directivity diagramsand pie charts as used in economic statements.

The Engineering drawing handbook makes a number of recommendations, including thefollowing:

(a) Line thicknesses should be graded so that thickest to thinnest lines are—

(i) curve to be plotted;

(ii) graph axes;

(iii) major grid lines; and

(iv) minor grid lines.

(b) The thicknesses of these lines should be compatible with readability and any reductionin size with minimum thicknesses being 0.35, 0.25, 0.18 and 0.12 mm for the linegroups given above.

(c) In certain circumstances, quantities to be graphed should be drawn with differentlinetypes e.g. continuous, dashed or dotted. See Figure 10.2 for an example.

(d) Plotted points from experimental data should be shown when necessary and as opencircles, or with triangles or squares when multiple quantities are graphed on the sameaxes. The use of crosses is not recommended.

(e) Depending upon the data, experimental curves may be drawn on a data point to datapoint basis with straight lines between each data point or alternatively, a curve of bestfit is drawn with data points as indications of the likely behaviour of a typical system.

(f) The name of each reference axis should be parallel to the axis placed in a manner thatgives readability and a generally pleasing appearance.

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FIGURE 10.1 SPECTROGRAM OF A BABY’S DISTRESS CRY

(Reproduced courtesy of CSIRO — Division of Radiophysics. Reading taken in 1981)

NOTE: Graph contains frequency and amplitude versus time.

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FIGURE 10.2 VOLTAGE COLLAPSE IN FRANCE, 19 DECEMBER, 1978*

* (Adapted from A. Cheimanoff and C. Corroyer, Power failure of 19th December, 1978, RGE, April

1980, pp 280-296)

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CHAPTER 11

NOTES ON DRAWING PRODUCTION

11.1 GENERAL

Drawing by hand is a practice that has declined in recent years with the advent of computer-aided drafting (CAD) software. However, there are many manually produced drawings inmost established drawing offices and it is unlikely that all drafting in the future will be CADproduced, nor will all existing drawings be redrawn on CAD. There will thus remain the needfor manual drafting and manual amending of existing drawings.

11.1.1 Cautionary note

Generally the removal of original drawings from the drawing office should be avoided. Insome instances the original is required to be sent to other offices for copying or storage butwhere possible copies of the original should be used instead.

A great deal of time and money is invested in the production of drawings and manuallyproduced drawings especially need protection from damage or loss.

11.2 EQUIPMENT REQUIRED

Drafting officers will most likely own their own instruments for the purpose of producingdrawings.

A drafting officer will have a range of instruments, lead pencils of various grades, erasersboth soft and hard, erasing shield, lettering stencils, curves and templates, ink drafting pens,compass and scale rules. No attempt is made to suggest a minimum list of equipmentrequired for drafting, and other publications, such as the Engineering drawing handbook(described in Appendix A), have a list.

In most offices, each drafting officer will have a drawing board or CAD workstation. Thedrawing board consists of a flat smooth board, similar to a table top covered with a layer ofvinyl, mounted on a stand. The drawing board generally has a drawing machine mounted onit. The machine consists of a head, with two scale rules attached at 90 degrees, which iscapable of rotation about their intersection. The head is mounted on a mechanism thatallows the head to be placed anywhere on the drawing board.

The drawing board has adjustment for vertical height on its stand and also for the angle ofinclination. The board is often big enough to mount an A0 size drawing sheet.(See Figure 11.1.) A seat adjustable in height is also provided.

If the drawing office has a large staff, tracers may be employed to ink in drawings producedin pencil by drafting officers, but generally the drafting officer will produce the drawings inpencil or ink.

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FIGURE 11.1 TYPICAL DRAWING BOARD WITH DRAWING MACHINE

11.3 DRAWING TECHNIQUES

A first and major consideration will be deciding on the size of drawing sheet to be employed.The size of the drawing sheet will be governed by several factors including the complexity ofthe final drawing and the needs of the field users, e.g. drawings may have to form part of ahandbook such as an operator’s manual.

Consideration of the overall layout must be given before any drafting commences. Thedrafting officer may rough out the drawing using a blue pencil to establish that theinformation will fit on the drawing sheet. The use of a blue pencil saves the drafting officerfrom removing the roughing out lines as blue lines do not appear on copies of the drawingwhen printed in a dyeline process. The drawing is then inked in, or pencilled in usingdifferent grades of pencil, to indicate the various sections and functions within a drawing.

When drawing with pencil on plastic drafting film, special pencils are available which whenapplied to film will not easily smudge.

It is vital that the surface of plastic drafting film in particular be kept clean or otherwise inkfrom drafting pens will not properly adhere to the surface. Drafting problems can also beexperienced if an attempt is made to ink across a surface that has been subject to eitherpencil or ink erasure, as the ink may not adhere to the sheet properly.

Having erased unwanted markings on a drafting film, the surface will require restoration sothat ink (and sometimes pencil) will draw evenly on the surface. This can be achieved byrubbing a fine powder (available from drawing office equipment suppliers) into the affectedsurface using a clean rag. It must be noted that the restored surface is not as good as theoriginal and when drawing over a restored surface with ink, care must be taken.

If an erasure of a pencil drawing on film is required, a clean plastic pencil eraser will besufficient to remove the unwanted markings. Usually the area being erased will be maskedby an erasing shield to minimize the amount of drafting surface and wanted material beingaffected. If a lot of erasing needs to be carried out, a motorized eraser can be used. Caremust be taken with this tool as the rotating eraser upon a surface can generate significantheat and there is the possibility of damage to the drafting film.

Erasure of an ink mark on film or paper will require a coarser grade of eraser which is moreabrasive than a pencil eraser. Ink is more difficult to remove having soaked into the surfaceslightly. An alternative to using the coarse eraser on film is to use a moistened pencil eraser,and this is preferred as less damage is done to the film. In some circumstances, particularlycleaning up fine overruns of ink, the use of a razor blade or scalpel blade might be used,however great care must be exercised as this operation can cause damage to the draftingfilm surface.

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If a drafting film is damaged with a hole or cut, the film or paper can be repaired with atransparent sticking tape applied to the back of the sheet.

11.4 DRAWING REPRODUCTION

There are two common methods of reproduction. The first method is photocopying. Manydrawing offices now have copying machines capable of copying drawings up to A0 size. Thesecond method of reproduction is to use dyeline prints in which the original drawing isplaced over a sensitized sheet of paper and then passed through a machine containing anultraviolet light source and ammonia damping; the result is a copy of the original drawing.Contrast of line weight can be adjusted by changing the speed of the passing of thesensitized sheet and original drawing combination through the print machine. Thedisadvantage of the second method is that the original drawing needs to be translucent.

Some drawing offices use sensitized drafting film (transparencies) so that copies ofdrawings are made with the copies becoming new drawings. This process enables speedierproduction of new drawings. An example would be where a drawing of a building plan ismade and services such as electrical, lighting, plumbing and office equipment aresuperimposed on it. Time is saved by producing one drawing showing the essential buildingoutline, then making transparencies and adding details of the different services on each ofthe transparencies.

11.5 NOTES ON COMPUTER-AIDED DRAFTING (CAD) EQUIPMENT AND SOFTWARE

11.5.1 General

CAD software must be distinguished from other graphical software which produces pictureson screens, particularly the sketch-types of software. A principal feature of CAD software isthat drawing information is contained as sets of vectors in a database. Sketch-type softwarestores graphical information as dots. This means that sketch-type software cannot beenlarged to show finer detail; enlargement in this case will only show an exaggerated pixellayout.

CAD has a distinct advantage over manual drafting with respect to the editing capabilities.Editing with CAD can greatly reduce the time required to produce new drawings as, forexample, new drawings can be built up by importing information from existing drawings.There is also the advantage that any changes to drawings may be performed seamlessly,that is, without any evidence, such as old line marks being left behind. The opportunity toproduce very clear paper copies of drawings is also enhanced by the use of CAD.

Production time for an original drawing can be less with manual techniques than CAD,depending on the type of drawing. It must be kept in mind that CAD is only a tool to producedrawings. Having CAD drawings of circuit diagrams, using a cell library of symbols orapplications where there are many similar drawings, combined with the ease of cutting andpasting (using CAD), can mean reduction of time in drawing production.

The minimum requirements for a CAD package are:

(a) A processor and operating system.

(b) Input devices.

(c) Output devices.

(d) Data storage devices.

(e) Drafting software.

11.5.2 Configuration

CAD software can be operated using small or large computers, depending on theapplication. Complex applications, such as in the aerospace industry, will often have themost expensive and complex CAD systems being run on computers with fast processors andlarge memory. These computers are often used for storage of information and drawing files,and connected via a network to smaller computers. (See Figure 11.2.)

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FIGURE 11.2 CONFIGURATIONS OF COMPUTER SYSTEMS

11.5.3 Processors and Memory

Typical CAD software requires a minimum of 4 Mb RAM and will run on a desktop computerwith a 33 MHz, 32 bit processor. At a higher end of the market, machines are required tohave at least 16 Mb RAM and at least a 100 MHz, 32 bit processor. Most computers can runCAD software as long as the computer has the appropriate input and output drivers for thesoftware.

11.5.4 Input devices

The minimum required input devices would be a computer keyboard and a mouse. Adigitizing tablet is helpful to facilitate the creation and editing of a drawing.

11.5.5 Output devices

The most frequently used output device is a monitor (screen), although hard copy deviceswill be needed to produce the final output for field use. The two main hard copy devices arethe printer and the plotter. Both of these devices vary widely in size, speed and quality ofoutput, with the printer typically only being used to provide draft output of secondary printquality.

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11.5.6 Data storage

Data storage will usually be on magnetic media such as floppy and hard disks as well asmagnetic tape. As in any sensitive area, duplicate copies of data should be retained atremote locations so that backup is available in the event of a failure of the main storagemedium. All large offices will have a network and central computer. The data is stored oncentral data storage and a backup procedure used.

11.5.7 Software

CAD software varies widely in price and capability and the user must make a decision as towhat package will best suit the needs of the organization. CAD packages should conform tosome minimum specifications as outlined below:

(a) There should be some means by which drawings created on one CAD package can betransferred to another CAD package, i.e. by direct translation or data transfercapabilities.

(b) All commands should be accessible by at least two different methods, e.g. a keyboardand a pointing device or digitizer.

(c) The monitor screen should contain at least four different areas, these being :

(i) The drawing area.

(ii) The command line (suitable for typed commands).

(iii) A screen menu (suitable for the mouse or other pointer to point at commands).

(iv) A status line (containing coordinate, layer information or similar).

(d) Drawing output can be produced by printers or plotters.

(e) Drawings may be stored and retrieved from convenient magnetic media as required.

(f) Libraries of standard or often used symbols may be created and accessed by anydrawing.

(g) The system, at turn-on, should be able to be customized to the user’s requirements.

11.6 CAD TECHNIQUES

11.6.1 General

An efficient use of CAD will be facilitated by the use of a uniform or consistent approach interms of the final drawing composition and how the drawing is assembled. A primaryconsideration is the use of layers/levels, the use of colour and the use of symbols (whichshould be drawn to relevant Australian and New Zealand Standards).

11.6.2 Layers (levels)

Layers (also referred to as ‘levels’) in CAD can be considered as being analogous to sheetsof clear film which are overlayed on each other to give the final drawing. Each layer shouldcontain items of similar nature. For example, on a building services drawing, the mainelectrical wiring could be on its own layer, water plumbing on another, gas plumbing on yetanother, lighting and air conditioning all on their own layers. The idea is that if certaininformation is not required, that information, on its appropriate layer, may be visuallyremoved from the final drawing without destroying that information. There will be less effortrequired to produce drawings detailing each service using level/layer techniques.

11.6.3 Colour and line thickness

On some CAD systems, colour is useful during the production of a drawing by allowing theviewing and identifying of the different entities of the drawing in a time efficient manner.Colour is also more relaxing to the eye. The translation of colour on a CAD screen to thepaper copy (usually monochrome) can be carried out by allocating different colours todifferent line (and hence pen) thicknesses. For example, in the production of the circuitdiagram of a motor control circuit, the main motor circuit wiring and supply lines will typicallybe of 1 mm thick lines. The control circuit wiring will typically be of 0.5 mm thick lines. Thusthe main wiring and control wiring will typically be drawn with different colours on themonitor.

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11.6.4 Symbols

The use of a library of symbols for standard items such as resistors and capacitors will helpin the production of drawings that adhere to Australian and New Zealand Standards as wellas company/customer requirements. These symbols are often kept in libraries of symbolswhich may have been purchased as a part of the CAD software, or purchased separately as‘third party’ software (i.e. software not produced by the manufacturer of the CAD packageitself), or developed in-house in large organizations. Standards Australia has most of theelectrical drawing symbols available in electronic form for popular CAD packages. (SAASP009 Graphical symbols for electrotechnical documentation—Electronic version ofAS 1102—1989.)

11.6.5 Initial drawing set-up

Having dealt with layers, colours and symbols, it would be useful to consider the initialdrawing set-up. The drawing should start with a standard drawing sheet which specifies thedrawing size, some (if not all) layers to be used on the drawing, colours associated with eachlayer, line types (e.g. continuous, dashed, centre-line, etc., lines), the font or fontsassociated with any text, the size and placement of objects used whilst dimensioning, etc.The initial drawing set-up will also assist in maintaining uniformity as well as speed up thedrawing process.

This information would be kept in a seed file for use as a standard set-up. An organizationcould have a few seed files, for example 2-dimensional, 3-dimensional and project files.

11.6.6 Producing the hardcopy

A drawing will become useful once it has been copied onto paper for field issue. Usually aplotter will be used for this purpose and here, there is one of the possible departures frommanual drawing practice, depending on the style of management. A plotter that is designedas an A3 plotter will accept sheets of paper that have been cut to A3 size. AS 1100.101,Technical drawing, Part 101: General principles specifies a drawing frame of 400 ×277 mm be used on A3 sheets (with 10 mm margins on each side). Owing to the need of theplotter to grip the paper (usually with pinch rollers along two sides), the maximum extent ofthe drawing may be less than that specified above. It is unlikely that plotter manufacturerswill redesign their products to allow the above recommended drawing frame to be drawn.

Some options available are:

(a) Using pre-printed drawing sheets whilst ensuring that the actual CAD drawing doesnot exceed the plotter’s limits.

(b) Using oversize paper on a larger plotter and trimming the excess paper off.

(c) Adjusting the size of the drawing to what the plotter will allow and living with a drawingthat is not exactly in accordance with Australian or New Zealand Standards, or withnon-preferred sheets such as the B-series of sheets in Table 2.4.

Option (a) may be the most preferable, although it involves additional initial cost to providethe pre-printed sheets.

11.7 ORIGINAL DRAWINGS AND MAGNETIC MEDIA

As with manually produced drawings, there is a need for the original CAD drawings to bemaintained in a location set aside for the purpose. This will ensure that all amendments areproperly placed on a registered drawing and that all field copies contain exactly the sameinformation for a given edition of a drawing.

It must be kept in mind that in several respects, magnetic storage media are subject tocertain fragilities and the possibility of the failure of the master with hardware or softwareproblems is always present. Several techniques might be employed to ensure that any datacorruption will have minimal impact upon a drawing office. These could include the use ofsecurity passwords and audit trails when using networked computers which log all activity ona particular drawing or drawing session. All drawings which undergo editing should bebacked up on a media other than the master media (this might include the use of otherseparate magnetic media) or an effective archive system.

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Strict control should be exercised with respect to portable magnetic media (i.e. floppy disks,tape) and the use of modems capable of accessing bulletin boards, etc., so as to limit thespread of computer viruses. The drawing office computers should also maintain and usereputable virus checking programs.

Where the CAD system is networked, some offices have daily archiving of all files which isdone by the system network operator rather than the individual workstation operator.

There should be security measures to protect a company’s or a clients’s intellectual propertyin drawings. Many drawings may be produced for patent purposes or have other legalstanding so that indiscriminate distribution of certain drawings may prejudice a company’s orindividual’s future.

The confidentiality of an organization’s intellectual property is very important in regard tocomputer-aided design and drafting.

If a CAD drawing is given to another organization in electronic form, the original firm’s logoshould be replaced by identification in normal font. This is a safeguard against unauthorizeduse of the firm’s logo.

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APPENDIX A

LIST OF STANDARDS AND REFERENCE MATERIAL(Numerical order)

AS 1000

ISO 1000 The International System of Units (SI) and its applicationProvides a summary of the system, gives rules on how derived unitsmay be formed, and affords a selection of multiples and sub-multiplesof units for application in the various fields of technology.

AS 1046 Letter symbols for use in electrotechnologySpeci f ies le t ter symbols for e lec t r ica l , e lec t ron ic andtelecommunications fields

AS 1046.1 Part 1: General

AS 1046.2 Part 2: Telecommunications and electronics

AS 1046.3 Part 3: Logarithmic quantities and units

AS 1046.4 Part 4: Symbols for quantities to be used for rotating electrical

machines

AS 1100 Technical drawing

AS 1100.101 Part 101: General principlesSets out the basic principles of technical drawing practice, and coversterminology and abbreviations used in technical drawings; materials,sizes and layout of drawing sheets; types and thicknesses of lines;types and dimensions of letters, numerals and symbols; drawingscales; projectioning; sectioning; dimensioning and geometrytolerancing and the conventional representation of features and parts.Appendices provide information on the development of pictorialdrawings and geometry tolerancing.

AS 1100.401 Part 401: Engineering survey and engineering survey design

drawingSets out recommendations for the preparation of survey plans forengineering work and the illustration of proposed, designed andexecuted engineering works based on such survey plans.

AS 1101 Graphical symbols for general engineering

AS 1101.6 Part 6: Process measurement control functions and instrumentationSpecifies symbols and an identifying code system for depictinginstruments, instrumentation systems, process computer, and shareddisplay and control functions in the field of process measurement andcontrol in the process industries. Examples of use of the symbols aregiven.

AS 1102 Graphical symbols for electrotechnologyProvides graphical symbols for drawings and diagrams.

AS 1102.8 Part 8: Symbols for location diagrams(to be redesignated

AS/NZS 1102.111)

Covers symbols on location diagrams for electrical equipment,electrical lighting, security and communication services, reticulationplans of electrical power systems and networks, topological maps ofpower supply systems and location of airport lighting.

AS 1102.12 Part 12: Electric tractionProvides symbols for electric traction purposes.

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AS 1102.101 Part 101: General information and general indexProvides general information on the structure of the AS 1102 series,the terminology used, the numbering, presentation and use of thesymbols, their adaption to computer-aided drafting (CAD) systemsand a general index.

AS 1102.102 Part 102: Symbol elements, qualifying symbols and other symbols

having general applicationProvides information on symbol elements, qualifying symbols andother symbols having general application to the AS 1102 series.

AS 1102.103 Part 103: Conductors and connecting devicesProvides symbols for conductors and connecting devices, includingterminals and cable fittings.

AS 1102.104 Part 104: Passive componentsProvides symbols for passive components such as resistors,capacitors and inductors, ferrite cores, magnetic storage matrices,piezoelectric crystals, electret and delay lines.

AS 1102.105 Part 105: Semiconductors and electron tubesProvides symbols for semiconductor devices and electron tubes.

AS 1102.106 Part 106: Production and conversion of electrical energyProvides symbols for the production and conversion of electricalenergy, including windings, machines, transformers, reactors, primarycells and accumulators.

AS 1102.107 Part 107: Switchgear, controlgear and protective devicesProvides symbols for switchgear, controlgear and protective devices,including starters, relays, proximity and touch-sensitive devices,igniters and flag indicators.

AS 1102.108 Part 108: Measuring instruments, lamps and signalling devicesProvides symbols for measuring instruments, lamps and signallingdevices, indicating/recording/integrating instruments, countingdevices, thermocouples, telemetering devices and electric clocks.

AS 1102.109 Part 109: Telecommunications — Switching and peripheral

equipmentProvides symbols for telecommunications switching and peripheralequipment, transducers, recorders and reproducers.

AS 1102.110 Part 110: Telecommunications—Transmission

Provides symbols for telecommunications transmission, includingtelecommunication circuits, antennas, radio stations, microwavetechnology, frequency spectrum diagrams and fibre optics.

AS/NZS 1102.111 Part 111: Architectural and topographical installation plans and

diagramsSee AS 1102.8.

AS/NZS 1102.112 Part 112: Binary logic elementsProvides symbols for logic functions and their usage. The symbolshave been prepared with a view to electrical applications but may alsobe applied to non-electrical systems.

AS/NZS 1102.113 Part 113: Analogue elementsProvides symbols to represent functions and devices for operatingand producing analogue quantities.

AS/NZS 1103 Preparation of documents used in electrotechnologyAt the time of publication, the following were in the course ofpreparation:

AS/NZS 1103.1 Part 1: General requirementsProvides general rules and guidelines for the preparation ofelectrotechnical documents.

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AS/NZS 1103.2 Part 2: Function-oriented diagramsProvides rules for function-oriented diagrams such as overviewdiagrams, function diagrams and circuit diagrams.

AS/NZS 1103.3 Part 3: Connection diagrams, tables and listsProvides rules for preparation of connection diagrams, tables andlists.

AS/NZS 1103.4 Part 4: Location and installation documentsProvides rules for documents mainly used for installation work, suchas arrangement or installation drawings for site, buildings andequipment.

AS 1104 Informative symbols for use on electrical and electronic equipmentEstablishes uniform principles for the standardization of graphicalsymbols used on electrical and electronic appliances and equipmentfor informative purposes.

AS 1104S Individual symbol sheetsThese are single sheets showing, in a size suitable for photographicreproduction or incorporation in artwork, the individual symbolsreproduced in miniature in AS 1104.

AS 1203 Microfilming of engineering documents (35 mm)Specifies essential requirements for the satisfactory microfilming ofengineering drawings and other documents onto 35 mm film usingeither roll film or camera cards.

AS 1852 International Electrotechnical Vocabulary(Various parts) The parts of AS 1852 contain terms and definitionsassociated with a particular aspect of electrotechnology.AS/NZS 1852.0 (in course of preparation) will provide an index anddescription of each of the parts.

AS 3702 Item designation in electrotechnologyProvides guidance for the formulation and application of discrete itemdesignation for parts used in electrotechnology. The designationcorrelates the item in different diagrams, parts lists, circuitdescriptions, instructions and in the equipment.

SAA HB7 Engineering drawing handbookContains information on technical drawing practice based onAustralian Standards. Provides a background and an explanation ofthe Standards, as well as details on drafting equipment andtechniques. A guide for students and practitioners on technicaldrawing.

IEC Mult i l ingual Dict ionary of Electr ic i ty , Electronics and

Telecommunications, Volume 2A reference work containing all the terms and definitions of the IEC*publication on electrotechnical vocabulary (published also as theAS 1852 series). The terms are listed alphabetically. Volume 2 hasEnglish language terms.

*IEC is the International Electrotechnical Commission.

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APPENDIX B

ITEM DESIGNATION—LIST OF LETTER CODES FOR THEDESIGNATION OF KIND OF ITEM

Lettercode

Kind of item Examples

A Assemblies, subassemblies Amplifier using discrete components, magnetic amplifiers, lasers,masers, printed circuit boards

B Transducers, from non-electrical quantityto electrical quantity and vice versa

Thermoelectric sensors, thermoelectric cells, photoelectric cells,dynamometers, crystal transducers, microphones, pickups, loud-speakers, synchros, resolvers, earphones

C Capacitors Static and synchronous capacitors, capacitor-resistor units

D Binary elements, delay devices, storagedevices

Digital integrated circuits and devices, delay lines, bistableelements, monostable elements, core storage, registers, magnetictape recorders, disc recorders

E Miscellaneous Lighting devices, heating devices, cooling devices, earthingdevices, devices not specified elsewhere in this list

F Protective devices Fuses, overvoltage discharge devices, arresters, surge diverters

G Generators, power supplies Rotating generators, rotating frequency converters, batteries,supply devices, oscillators

H Signalling devices Optical and acoustical indicators, light emitting diodes, buzzers,bells

J —

K Relays, contactors

L Inductors, reactors Induction coils, line traps, reactors (shunt and series)

M Motors

N Analogue elements Operational amplifiers, digital to analogue converters, voltageregulators

P Measuring equipment, testing equipment Indicating, recording, and integrating measuring devices, signalgenerators, clocks, counters

Q Switching devices for power circuits Circuit-breakers, isolators, moulded case circuit-breakers,reclosers, fault throwers, earthing switches

R Resistors Adjustable resistors, potentiometers, rheostats, shunts, thermistors

S Switching devices for control circuits,selector switches

Switches, control switches, pushbuttons, limit switches, selectorswitches, selectors, dial contacts, connecting stages

T Transformers, voltage regulators (power) Voltage transformers, current transformers, power transformers,power voltage regulators (transformers, and induction types),potential devices

U Modulators, changers Discriminators, demodulators, frequency changers, coders,inverters, converters, telegraph translators, modems

V Tubes, semiconductors (discrete) Electronic tubes, gas-discharge tubes, diodes, transistors,thyristors, opto-isolators, solion diodes

W Transmission paths, waveguides,antennae

Conductors, cables, busbars, waveguides, waveguide directionalcouplers, dipoles, parabolic aerials

X Terminals, plugs, sockets, links, joints Disconnecting plugs and sockets, jacks, terminal boards, solderingterminal strips, links, cable sealing ends and joints

Y Electrically operated mechanical devices Brakes, clutches, pneumatic valves

Z Networks, hybrid transformers, filters,equalizers, limiters

Cable-balancing networks, compandors, crystal filters

NOTE: See Chapter 3 for further information

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APPENDIX C

EXAMPLES OF CIRCUIT DIAGRAMS

C1 EXAMPLES OF COMPLETE CIRCUIT DIAGRAMS Examples of complete circuitdiagrams are shown in this Appendix. These figures are intended to show the application ofthe recommendations given. They are intended only to show the methods of representationand are not meant as recommendations concerning the equipment.

The examples represent equipment of different kinds. It is not the intention to prescribe thatthe method of representation, chosen here for a certain kind of equipment, is specific forequipment of this kind.

The examples are:

(a) Figures C1 to C5 show five variants of a circuit diagram for the same equipment, amilling machine.

(b) The main circuits are shown on Figure C1, the auxiliary circuits on Figure C2, thesebeing Sheets 1 and 2 of a series, all in horizontal circuit representation. The figure isan example of mixed representation, i.e. detached and semi-attached. Therelationship of the elements belonging to one item is shown partly by the linkagesymbol and partly by references.

Example: 2/D stands for Sheet 2, Row D.

(c) In Figure C3, part of the complete circuit is shown, using vertical circuit representation.The figure is an example of semi-attached representation with straight mechanicallinkage symbols. The table to the right shows the item designations for contacts,relays and similar, as well as the location of the items.

(d) In Figure C4, the circuits of Figure C3 are shown on one sheet, using vertical circuitrepresentation. Detached representation is used with column references. However,two mechanical linkage symbols, which aid understanding and are easy to insert, havebeen shown. The inset diagrams for contacts and relays are shown at the bottom ofthe diagram.

(e) Figure C5 shows the same information as Figure C4, using the line reference system.Each line of the system is numbered consecutively throughout all sheets of the circuitdiagram and the number component of the item designation corresponds to the linenumber in which it or its principal subcomponent, e.g. operating coil, appears. Insetsat the bottom of the diagram show the line number location for associatedsubcomponents of the principal subcomponent.

(f) In Figure C6, the line reference system is also used. Control circuit numbers areshown at the bottom of the diagram. Circuits for normal power supply are designated1−4, circuits for emergency power supply 5−7. Circuits for main power 11−13 and21−23 as referenced in the table, are not shown here, as they are of no interest for theexplanation of the system.

(g) Figure C7 shows the circuit diagram of an equipment for starting a motor in twodirections with automatic braking by countercurrent when the handwheel of thedrumswitch S1 is brought back to its zero position. In the case of successive impulsesfor the same direction of rotation, starting has priority to braking.

This figure is an example of detached representation of a simple item of equipment inwhich the relationship between the elements of each unit can easily be seen from thereference alone. It also shows the function of a centrifugal switch S3. The contacts ofdrum switch S2 are arranged in line and a graph of the drum is drawn against it.Therefore, it is unnecessary to supply an inset diagram to aid the clarity of the circuitdiagram.

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(h) Figures C8 and C9 represent a part of the control equipment for a transformer station66/11 kV substation.

Owing to the size of the equipment, the circuit diagram consists of several sheets, twoof which are shown here. Sheet 1, Figure C8, shows the main circuits of a transformerwith protective relays and measuring devices, and sheet 21, Figure C9, the auxiliarypower supply.

Semi-attached representation is generally used. For each relay all the contacts areshown adjacent to the coil symbol in the circuit diagram.

The contents of each diagram sheet are so obvious that the referencing can consistonly of sheet numbers. Therefore squares or columns for the referencing are not usedhere.

(i) Figure C10 represents a relay set of a telephone system drawn in detachedrepresentation.

This equipment can be used in a different mode by removing a connection which isfound at grid reference A1 and explained in Note 2.

This figure also illustrates the sequence of point-to-point wiring.

(j) Figure C11 shows a video amplifier and power supply with PNP and NPN transistors.In this example, physical values for resistors, capacitors, the fuse and transformer aregiven.

(k) Figure C12 is an example using the tabular system for symbol location (seeClause 4.4 and Figure 4.6).

(l) Figure C13 is an example of a block diagram for an intercom system.

(m) Figure C14 is an example of a circuit diagram for an intercom system.

(n) Figure C15 is an example of a line diagram for a power distribution system, usingsingle-line representation.

(o) Figure C16 is an example of a basic logic diagram.

(p) Figure C17 is an example of detached representation.

C2 SYMBOLS IN EXAMPLES Some of the examples show switches with a hinge point(symbol 107-02-02, Appendix D). It is currently more common to use the symbol without thehinge point (symbol 107-01-01, Appendix D).

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FIGURE C1 EXAMPLE OF MIXED REPRESENTATION WITH HORIZONTAL

ORIENTATION — MAJOR CIRCUITS

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FIGURE C2 EXAMPLE OF MIXED REPRESENTATION WITH HORIZONTAL

ORIENTATION—AUXILIARY CIRCUITS

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FIGURE C3 SEMI-ATTACHED REPRESENTATION WITH VERTICAL ORIENTATION

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FIGURE C4 EXAMPLE OF DETACHED REPRESENTATION WITH VERTICAL ORIENTATION AND

COLUMN REFERENCES

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FIGURE C5 EXAMPLE OF DETACHED REPRESENTATION WITH VERTICAL ORIENTATION AND

LINE REFERENCES

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FIGURE C6 EXAMPLE OF DETACHED REPRESENTATION USING THE LINE

REFERENCE SYSTEM

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FIGURE C7 EXAMPLE OF DETACHED REPRESENTATION WITH GRAPHICAL

REPRESENTATION OF SWITCHES S2 AND S3

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FIGURE C8 EXAMPLE OF SEMI-ATTACHED REPRESENTATION ON A NUMBER OF

SHEETS—SHEET 1 SHOWS MAJOR CIRCUITS

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FIGURE C9 SHEET 21, DETACHED REPRESENTATION OF AUXILIARY POWER SUPPLY

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FIGURE C10 DETACHED REPRESENTATION, TELEPHONE RELAY SET WITH ROW AND

COLUMN REFERENCES

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FIGURE C11 VIDEO AMPLIFIER AND POWER SUPPLY CIRCUIT

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FIGURE C12 EXAMPLE USING TABULAR SYSTEM FOR SYMBOL LOCATION

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FIGURE C13 EXAMPLE OF A BLOCK DIAGRAM FOR AN INTERCOM SYSTEM

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FIGURE C14 EXAMPLE CIRCUIT DIAGRAM FOR AN INTERCOM SYSTEM

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NOTE: Hinge point of the switch contacts have been omitted in this diagram

FIGURE C15 EXAMPLE OF A LINE DIAGRAM FOR A POWER DISTRIBUTION SYSTEM USING

SINGLE-LINE REPRESENTATION

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FIGURE C16 EXAMPLE OF A BASIC LOGIC DIAGRAM

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FIGURE C17 EXAMPLE OF DETACHED REPRESENTATION SHOWING GRID REFERENCES,

WIRE NUMBERS AND PROGRAMMABLE CONTROLLER INPUT AND OUTPUT ADDRESSES

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APPENDIX D

GRAPHICAL SYMBOLS

D1 GENERAL This Appendix contains a selection of graphical symbols taken from theAS 1102 and AS/NZS 1102 series of Standards, Graphical symbols for electrotechnology.The AS 1102 series consists of 14 parts described in Appendix A.

D1.1 Relationship with IEC symbols The symbols are identical with those internationallyagreed with the International Electrotechnical Commission (IEC), except where establishedusage in Australia or New Zealand makes unqualified acceptance of the IEC symbol difficult.In such cases an alternative symbol may be shown with the object of adopting the IECsymbol as soon as possible. Only one form of any symbol should be used on a singlediagram or series of drawings.

AS 1102, Part 12: Electric traction contains symbols which have been developed locally andhave not been adopted by the IEC.

D2 APPLICATION OF GRAPHICAL SYMBOLS

D2.1 Combinations and composition of symbols AS 1102 does not give all the possibleexamples. Any symbol may be composed by combining existing symbols given in thatstandard, and by combining existing symbols with the letter symbols of AS 1046, Lettersymbols for use in electrotechnology, Part 1: General, or Part 2: Telecommunications andelectronics. Appendix E provides an extract from AS 1046, Part 1, which shows somequantities and their letter symbols.

If the required parts for building a symbol are not found in the Australian or New ZealandStandards, graphical or letter symbols established by other sources may be used, but insuch case their meaning should be clearly stated.

D2.2 Choice of symbols for a diagram The simplest form of symbol that is adequate forthe particular purpose should be used. The chosen form should be used consistentlythroughout the diagram.

The basic rules for the choice of a symbol are as follows:

(a) Use the simplified form of symbol; or

(b) Use the detailed form of symbol; or

(c) Use the complete form of symbol.

NOTE: Figure D1 illustrates various forms of a transformer symbol.

D2.3 Size of symbols Precise dimensions and proportions of graphical symbols aredifficult to specify. The symbols shown in this handbook have been drawn to a sizeconvenient for publication and comprehension. The sizes of symbols relative to one anothermay be changed to suit the circumstances of a given drawing or application.

The relative sizes of symbols should be preserved except where it is necessary to enlarge asymbol to give it prominence in a diagram or to provide adequate space within or around it toshow symbols for associated components, or for coding.

At all times, however, the relative proportions of the symbols should be maintained so thateach symbol is unique and immediately recognizable.

D2.4 Orientation of symbols The meaning of a symbol is not altered by any change inorientation or mirror-image reversal.

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Example 1:

For a simple explanatory diagram, such as a block diagram, and especially where single-linerepresentation can be used, it is sufficient in many cases to use the general or simplifiedform of symbols. (See Figure D1(a).)

Example 2:

For an explanatory diagram intended to aid a detailed study, such as a circuit diagram, thesimplified symbol may not be sufficient. For a transformer, it may be necessary to use amore detailed form of symbol including supplementary or qualifying symbols showing theconnection of windings and the vector symbol group. (See Figure D1(b).)

Example 3:

For a diagram in which all parts, such as windings, terminals and their designations have tobe shown in detail, it may be necessary to use the complete form of symbol. (SeeFigure D1(c).)

(a) Simplified form of symbol (b) Detailed form of symbol

(c) Complete form of symbol

FIGURE D1 VARIOUS FORMS OF A TRANSFORMER SYMBOL

D3 SELECTION OF SYMBOLS FROM THE AS 1102 AND AS/NZS 1102 SERIES

D3.1 Symbol numbers The symbol numbers used in this Appendix correspond to thesymbol numbers used in the AS 1102 and AS/NZS 1102 series. The symbol numbers havethree components. The first component is the number of the part of AS 1102, the secondcomponent is the section number within that part and the third component is the symbolnumber within that section. Thus symbol number 102-02-04 is the symbol in AS 1102,Part 102, Section 2, Item 4.

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AS 1102 and AS/NZS 1102, Parts 101 to 113, replaced an earlier series designated AS 1102Parts 1 to 15. The ‘hundreds’ series were so numbered to avoid confusion between the twoseries. Parts 111, 112 and 113 show the symbol numbers without the ‘100’. For instance,symbol 111-03-01 is the same as 11-03-01 in AS/NZS 1102 Part 111. Note that there is aPart ‘112’ and a Part ‘12’ and that care should be taken with the symbol reference if there isa possibility of confusion.

Symbols with the designation A at the end of the symbol numbers, are symbols for local use.Most of these symbols have been developed because they were missing from the IEC list ofsymbols.

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D4 GENERAL INDEX OF GRAPHICAL SYMBOLS IN AS 1102 AND AS/NZS 1102

SymbolAS 1102 or

AS/NZS 1102

Part No

SymbolAS 1102 or

AS/NZS 1102

Part No

Amplifiers 110 Magnetic amplifiers 106

Amplifiers (Location symbols) 111 Masers 110

Analogue elements 113 Measuring elements 108

Measuring instruments 108

Batteries 106 Mechanical controls 102

Binary logic 112 Meters, intergrating 108

Microphones 109

Cables 103 Microwave 110

Capacitors 104 Modulators 110

Cells 105 Motion (direction) 102

Changers 110 Motors 106

Chassis connections 102

Circuit breaker 107 Networks 111

Clocks, electric 108

Coaxial lines 103, 107 Plugs 103

Coils 104, 107 Protective devices 102, 111

Conductors 103, 111

Connecting devices 103 Recorders 109

Contactor 107 Regulators, induction 106

Contacts 107 Relays 107

Controls, mechanical 102 Reproducers 109

Correctors, distortion 110 Resistors 104

Crystal, piezo electric 104

Current, types of 102 Selectors 109

Semiconductors devices 105

Delay lines 104 Signal, transmission 110

Demodulators 110 Signal, waveform 102

Detectors, ionizing radiation 105 Sockets 103, 111

Diodes 105 Starters 107

Discriminators 110 Switchgear 107

Switches 102, 107, 111

Earth connection 102

Electric traction 12 Telephony 109

Electron tubes 105 Terminals 103

Threshold devices 110

Force (direction) 102 Thyristors 105

Fuses 107 Traction 12

Transducers 109

Generators 106 Transductors 106

Transformers 106, 110

Inductors 104 Transistors 105

Instruments, indicating,

measuring, recording,

telemetering

108 Transmission direction

Tubes

102

105, 107

Isolator 105 Valves (see Tubes)

Jacks 103 Variability 102

Voltage, types of 102

Lasers 110

Location and installation

symbols

111 Waveform, signal 102

Logic 112 Waveguides 110

Loudspeakers 109 Windings 104, 106

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APPENDIX E

SELECTED QUANTITIES AND THEIR LETTER SYMBOLS

(Extracted from AS 1046, Part 1)

E1 DYNAMICS

Name of quantity Letter symbol

mass m

density (mass density) ρ

momentum p

(dynamic) moment of inertia I, J

force F

moment of force M

torque T

pressure p

work W

energy E, W

energy (volume) density e, w

power P

efficiency η

E2 THERMODYNAMICS


Thermodynamic temperature,

absolute temperature

T

temperature (Celsius)) t

heat, quantity of heat Q

temperature coefficient α

thermal conductivity λ

heat capacity C

specific heat capacity c

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E3 ELECTRICITY AND MAGNETISM


(electric) charge, quantity of electricity Q

surface density of charge σ

volume density of charge ρ

electric field strength E

(electric) potential V

potential difference, tension, voltage U

electromotive force E

electric flux Ψ

electric flux density, displacement D

capacitance C

permittivity, absolute permittivity, (capacitivity) ε

relative permittivity (relative capacitivity) εr

electric susceptibility χ, χe

electrization Ei

electric polarization P

electric dipole moment p

(electric) current I

current density J

linear current density A

magnetic field strength H

magnetic potential difference U, Um

magnetomotive force F, Fm

magnetic flux density (magnetic induction) B

magnetic flux Φ

magnetic vector potential A

self inductance L

mutual inductance M, Lmn

coupling coefficient k

leakage coefficient σ

permeability, absolute permeability µ

relative permeability µr

magnetic susceptibility χ, κ

magnetic moment (magnetic area moment) m

magnetization Hi,M

intrinsic magnetic flux density, magnetic polarization Bi, J

magnetic dipole moment j

resistance R

(continued)

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resistivity ρ

conductance G

conductivity γ, σ

reluctance R, Rm

permeance Λ

impedance Z

reactance X

quality factor Q

loss angle δ

admittance Y

susceptance B

active power P

reactive power Q

apparent power S

power factor λ

dissipation factor d

Poynting vector S

phase difference φ

number of turns in a winding N

turns ratio n

transformation ratio of an instrument transformer K

transformation ratio of a current transformer K

number of phases m

number of pairs of poles p

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APPENDIX F

EXERCISES

1 A square wave voltage may be expressed as a series expansion of sinusoids asfollows:

Produce a drawing starting at the first cos term and then progressive drawingsincluding up to the next three terms showing the development of a square wave fromthe sinusoids. The drawings should be annotated with descriptions of eachdevelopment and be suitable for instruction as in a text book. The title of your drawingset should be ‘DEVELOPMENT OF A SQUARE WAVE FROM SINUSOIDS’.

2 Using X−Y axes, draw an arbitrary curve. Starting on this curve, show thedevelopment of the determination of the gradient of a function. In a series of twofurther drawings showing greater detail of any chosen region of the curve, describethe principle of the derivative dy/dx = limit ∆ 0, ∆y/∆x as being the gradient of a function.

3 An experimental circuit was constructed as shown in Figure F1. The ambienttemperature was noted as 27°C.

For three values of base current, Ib = 5 µA, 10 µA and 15 µA, experimental values ofthe collector-emitter voltage Vce versus the collector current Ic were obtained as in thefollowing table.

Values of Ic (mA)

Vce

(volt)

0.1 0.5 1 2 4 6 8 10

Ib = 5 µA 0.36 1.14 1.16 1.18 1.23 1.27 1.30 1.33

Ib = 10 µA 0.73 2.4 2.5 2.6 2.7 2.7 2.8 2.8

Ib = 15 µA 1.17 3.8 3.88 3.98 4.15 4.31 4.46 4.6

Using a heat gun, the temperature in the vicinity of the transistor was raised to anominal value of 50°C. (In fact, in this experiment, the temperature varied widely fromthe nominal value as the experiment proceeded.) Ic was again noted against Vce, butonly with an Ib of 15 µA. Results obtained were as follows:

Values of Ic (mA)

Vce

(volt)

0.1 0.5 1 2 4 6 8 10

Ib = 15 µA 1.42 4.21 4.82 5.16 5.01 5.13 5.25 5.25

Using these sets of experimental values, draw curves of Vce versus Ic (the collectorcharacteristic). Annotate your drawings showing the temperature of each set ofcurves.

Also consider the following points. Will curves be drawn through each experimentalpoint or will the curves only show the trend in the behaviour of the transistor? Whatcan be said about the data obtained when the heat source was used? What usefultrend is shown with the data obtained when the heat source was used? Do youconsider the data obtained with Ib = 10 mA to be satisfactory?

4 A digital seconds counter may be constructed using a mains supply as a referencefrequency from which time may be derived. A block diagram of a counter is shown inFigure F2. From this, and using appropriate IC (integrated circuit) data books, draw acomplete circuit diagram using appropriate Standard symbols for the counter based onthe following description of operation.

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Supply is taken from a 240 V, 50 Hz source and applied to the primary winding of a240/6.3/6.3 V centre-tapped transformer via a 1 amp fuse. The 6.3 V secondarywindings are applied via resistors to zero crossing detector circuit consisting of a 741opamp acting as a comparator and to two (+ve and −ve) 5 V d.c. power supply circuitconsisting of bridge rectifiers, filter capacitors, 7805 and 7905 three terminalregulators. The output terminals of the regulators also have filter capacitors.

The output of the 741 opamp changes state every half cycle and the falling edge of theopamp output is fed to one input of a two input NAND gate (74LS00) and the output ofthis gate is counted by a circuit consisting of two 7490 decade counters which resetupon a count of 50 (i.e. every 1 second). (The second input to the NAND gate isconnected to a push-button used for suspending counting, see below.) The signal,which resets the MOD 50 counter is also fed to the first of a series of three furthercounters connected in cascade (i.e. the output of one feeds the clock input of thenext). These three counters are made from 7490 decade counters, and count seconds,tens of seconds and hundreds of seconds so that the maximum count is 999 seconds(approximately 16 minutes).

Each of the BCD outputs of the 999-second counters is fed to 7447 BCD-7 segmentdecoder/driver ICs which in turn drive appropriate common anode 7-segment LEDdisplays via suitable series resistors.

Counting may be suspended by pressing a push-button which places a logic 0 on thesecond input of a NAND gate following the opamp output.

The inverting and non-inverting terminals of the 741 opamp are each connected to theopposite secondary terminals of the transformer whilst the opamp power is taken fromthe output of the 7805 and 7905 three terminal regulators. The opamp output is fed tothe input of the MOD 50, 1 second counter.

The reset to zero is a pushbutton which, when closed, places a logic high (1) on the7490 counter reset lines.

NOTE: Drafting officers must determine for themselves all IC pinouts, the type of common anode 7-segmentdisplay and the size of any required resistors in the circuit. Sources of information include manufacturer andsuppliers catalogues.

5 Produce printed circuit board artwork for the digital counter described in Exercise 4. Atechnical sketch of the circuit may be required if Exercise 4 has not been formallyattempted.

6 Produce a short user’s manual for the digital counter described in Exercise 4. Includean isometric drawing of your counter in an appropriate housing.

7 A coal-fired power station requires auxiliary power to maintain operation. Produce asingle-line diagram of the electrical system required for the auxiliaries based on thefollowing description. Note that the voltage vectors can change angle when power ispassed through transformers. The voltage angle should be noted on the drawing.

A 660 MW generator is connected via a circuit breaker and isolator to two generatorand two auxiliary transformers with flexible braid links before each transformer. Thevoltage is generated at 23 kV with a −30 degree phase shift on the voltage of phase A.

The generator transformers are paralleled 390 MVA 330/23 kV YNd1 16.0% andconnect to the 330 kV switchyard.

The unit auxiliary transformers are 45 MVA 23/11 kV Dyn 11 9.9% with a neutralearthing resistor on the secondary winding. The two transformers are connected toeither end of No. 1 11 kV unit switchboard via circuit breakers which must bephysically moved from their normal position (‘racked out’) before an earth switch maybe closed on either side of the circuit breaker. One transformer is designated1A 23/11 kV unit auxiliary transformer, the second, 1B 23/11 kV unit auxiliarytransformer.

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FIGURE F1 EXPERIMENTAL CIRCUITS (EXERCISE 3)

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FIGURE F2 HAND-DRAWN BLOCK DIAGRAM (EXERCISE 4)

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SAA/SNZ HB3 :1996 192

The 11 kV unit switchboard is connected via rack out circuit-breakers to two each of—

(a) 2.4 MVA 11 kV/415 V Dyn1 8.9% transformers with neutral earthing (noresistors between neutral and earth);

(b) forced draught fans;

(c) induced draught fans;

(d) condensate pumps;

(e) 15 MVA 11/3.3 kV Dyn1 10.7% transformers with neutral earthing resistors;

(f) boiler feed pumps;

and one circulating water pump.

The 11 kV switchboard is wired so that one each of items (a) to (e) are connected ateither end of the board with a tie between the two ends being through a middle sectionwith circuit-breakers connecting the middle to the two ends. The circulating waterpump and two boiler feed pumps are fed via racked out circuit-breakers from thismiddle section.

One end of the 11 kV unit switchboard connects the 11 kV station switchboard withrack out circuit-breakers at either end of this link.

The 2.4 MVA transformers connect to separate 415 V unit switchboards with circuit-breakers also on the low voltage side.

The 15 MVA transformers connect to the two ends of the 3.3 kV unit switchboardwhich is wired in a similar manner to the 11 kV unit switchboard made up of threesections. The 15 MVA transformers have circuit-breakers on the low voltage side.Each end of the 3.3 kV switchboard is connected to—

(a) one auxiliary cooling water return pump;

(b) three pulverized fuel mills; and

(c) one pulverized air fan.

Each of these machines is connected via a combination fuse and isolator.

The middle section of the 3.3 kV unit switchboard is connected to a turbine oil pumpwhich is also connected by a combination fuse and isolator. The middle section joinsthe end sections of the 3.3 kV switchboard via circuit breakers.

Note that no information is given on further switchboard interconnections. Ensure thatyour single-line diagram finishes this neatly, e.g. use annotation such as ‘Link to 11 kVstation switchboard — refer drawing No. . .’. Do not leave switchboards or the like‘hanging’.

8 An architectural plan view of Lake Moondara Pumping Station has been provided (seeFigure F3). It is proposed to augment pumping capacity by providing another unit atthe western end of the station. In order to do this, the station will have an extension of4 m added on to the western side whilst retaining the existing western wall. In thisextension will be housed No. 6 pump unit placed in line with the existing five units.

It is required that:

(a) A 4 m wide roller door with a man-access door be provided in the western endof the extension.

(b) The earth pit and WC be moved to the north of their existing sites.

(c) A 150-watt floodlight be provided off the western wall of the extension.

(d) The existing control and starter cubicles be extended for No. 6 pump.

(e) Cable to No. 6 pump be run in an existing cable trench to a point east of No. 1pump, then a new trench is to be dug past the east of No. 1 pump to the wall,then the cable be run in a cable tray suspended 300 mm above the floorsupported every 600 mm off the southern wall and through to the extensionhousing No. 6 pump. This will also entail making a hole in the existing westernwall. The cable is then to run in a trench to the No. 6 pump.

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(f) The caretaker call-bell feeder and telemetry line is to be kept in service, and aminimum of disruption is to occur when repositioning these two lines off theextension. The junction boxes may remain where they are.

(g) Two sets of chain hung, three-luminaire fluorescent light fittings with two wayswitches (switches to be provided at the roller door entrance and at the existingwestern door) are to be provided as well as a 240 V general purpose outlet onthe southern wall of the extension.

Issue a drawing of the proposed extension in architectural plan view form. Thedrawing should be suitably annotated with respect to the works and conditions underwhich the works are to be carried out.

9 A three-cup anemometer is constructed using three hemispheres of 50 mm diameter,each mounted on a 30 mm approximate arm which are at 120 degrees with respect toeach other on a freely moving pivot.

At the centre of the pivot is a metal disc which moves with the anemometer cups. Thisdisc has slots cut out. Fixed to the pivot mounting is an infrared emitting diode underthe revolving disc facing upwards, whilst over the top of the disc facing downwards isan infrared photodiode. The revolving disc allows an infrared beam to pass each timea slot passes. The number of times the beam is cut in a time interval is a measure ofwindspeed.

Produce a 3rd-angle orthogonal drawing of an anemometer with the followingassumptions and conditions:

(a) The radial cup velocity when the cup is travelling parallel to the wind is thesame as the wind velocity. The cup radial velocity may be taken from the centreof the cup.

(b) The length of the cup mounting arm is to be determined so that in combinationwith a determination of the number of slot cut-outs, the windspeed may bedetermined every second for windspeeds of 1 km per hour upwards. (Refer toExercise 10 for detail on the electronic indication of windspeed.)

10 The anemometer in Exercise 9 is to display the windspeed in km per hour updatingevery second. It achieves this by counting the number of times an infrared beam isinterrupted in each second.

A one second time base is established using a 555 timer set up in a stable mode. Athree-digit, binary-coded decimal (BCD) counter is used to count the number ofinfrared beam interruptions with the falling edge of each interruption sent to the clockinput of the least significant counter. The reset of the least significant counterincrements the next significant, bit and so on. Each digit of BCD output of eachcounter is passed to a data-type bistable circuit device (commonly known as a ‘D-typeflip-flop’) which holds the value of the count at each second.

The 555 astable provides a clock signal for the ‘D-type flip-flops’ and also sends areset signal to all of the counters.

Since the ‘D-type flip-flops’ hold the value of the count at the end of each second, theiroutput may be fed to BCD-7 segment decoder drivers which in turn drive, viaappropriate resistors, a three digit 7-segment display.

Using suitable manufacturer’s and supplier’s catalogues, select appropriate ICs fortiming, counting, and latching as well as selecting suitable 7-segment displays andnominate the display voltage dropping resistors. Also nominate the values of theastable resistors and capacitors. Produce a circuit diagram for the anemometerensuring that a power supply is available, and a printed circuit board overlay and pcbartwork diagram for those items not mounted at the pivot point. Also select a suitablesize box to contain the pcb and display.

NOTE: The term ‘flip-flop’ is deprecated and is substituted by the terms ‘monostable trigger circuit’ or ‘bistabletrigger circuit’.

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FIGURE F3 PLAN — PUMPING STATION (EXERCISE 8)

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11 A coal-fired power station furnace carries light fly-ash (a constituent of the non-combustible material found in coal) in the furnace draft which is collected in a fabricfilter system prior to exhausting the furnace gases to the atmosphere. (The fabric filteracts in a similar manner to the collection bag in a domestic vacuum cleaner.)

The operation of the fabric filter is as described below.

Furnace gases are passed through the fabric filter bags of which there are 40 000 in40 cells of 1000 bags each. Gas passes from the inside to the outside of the bag,being drawn by an induced draft fan prior to discharge up the stack. Fly ash is caughton the inside of the bags and periodically the gas flow through a ‘cell’ of 1000 bags isstopped and the bags are given a shake with the fly ash falling down into an ashcollection hopper below. The frequency of the shake cycle is dependent on a numberof factors, including power plant output, but is typically determined by the differentialpressure (d.p.) between the inside and outside of the bags. A newer, cleaner bagwould offer less resistance to gas flow and hence have a lower d.p. than an older,dirtier bag.

The sequence of operation can be described as follows:

(a) Pre-shake dwell (closing of the cell outlet dampers)—3 s.

(b) Shake—20 s.

(c) Post-shake dwell (settling time to allow ash to settle)—50 s.

(d) Slip time (time between moving to start a shake on the next cell) depends onthe d.p. as follows:

(i) <1.2 kPa d.p.—500 s.

(ii) 1.2−2 kPa d.p.—250 s.

(iii) >2−2.3 Kpa d.p.—120 s.

(iv) >2.3 kPa d.p.—35 s.

Each cell outlet damper is opened and closed by a solenoid-operated, pneumaticactuator. Also each cell is shaken by a 5.5 kW electric motor mounted above the fabricfilter baghouse and mechanically attached to the bag shakers so that the bags areshaken at 6 Hz.

Produce a sequence diagram to describe the operation of the fabric filter.

12 Using either or both orthogonal and pictorial representations, show the PRINCIPLESof the following:

(a) The d.c. machine.

(b) Three-phase, squirrel-cage induction machine.

(c) Three-phase, wound-rotor induction machine.

(d) One-phase induction machine—shaded pole start.

(e) One-phase induction machine—capacitor start.

(f) One-phase induction machine—starter winding.

(g) Three-phase synchronous machine.

Note that these drawings may not (particularly the synchronous machine) show thenormal mode of operation. Drawings of the machines should be accompanied byappropriate voltage/current or torque curves as necessary to describe operation.

13 An overhead system for supplying traction current to a railway consists of a catenarywire with droppers spaced every three metres which support a nearly horizontalcontact wire. Traction current is collected by sliding pantographs mounted on therailway vehicle.

(a) Devise a means of connecting the dropper to the contact wire such that therewill not be any interference to the contact surface of the contact wire. Assumethe droppers are always hung vertically.

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(b) In order to spread the wear on the pantograph collector pan, the contact wire isstaggered in a zig-zag manner about the centre of the railway track alignment.Determine likely positions and numbers of ‘pull-offs’ (tension cables or solidmembers transverse to the direction of the contact wire) needed to maintain amaximum stagger of 350 mm off centre when rounding a curve of 161 m radiusfor 15 degrees of curvature.

14 Electric traction systems and electric cranes are often controlled by means of a ‘drumcontroller’. A drum controller consists essentially of a contact drum, or cylinder,carrying insulated and interconnected segments which, when the drum is movedthrough certain angles, make contact with appropriate fixed contacts (called fingers) towhich the motors, rheostats/control electronics and supply mains are connected.

An older style series-parallel controller has rheostatic control with four seriesrheostats, progressively cut out by an eight-position (eight-notch) controller which alsomakes series and parallel connections between two d.c. motors (the motors have aseries field/armature connection).

The controller has the following operation:

Notch 0: All off.

Notch 1: All four rheostats and two motors in series.

Notch 2: One rheostat cut out.

Notch 3: Two rheostats cut out.

Notch 4: All four rheostats cut out, two motors still in series.

Notch 5: One rheostat cut out, remaining rheostats in series with the two motors inparallel.

Notch 6: Two rheostats cut out.

Notch 7: Three rheostats cut out.

Notch 8: All rheostats cut out, two motors still in parallel.

Draw a circuit diagram of the rheostats and motors with connection taps. Next to thecircuit diagram, draw a drum sequence table showing the drum connections neededfor each notch. Draw plan and elevation views of the drum controller.

15 Using ‘resistance paper’ (paper sheet with a uniform coating of resistive material)draw, using conductive ink, a sketch of the 500 kV single-circuit tower in Figure F4.The tower sketch stands on a conductive earth. Assume that phase A is at itsmaximum positive potential. Determine the potentials on phases B and C at this time.Using three d.c. sources, connect scaled potentials to the resistance paper at thevarious phase conductor locations with the earth potential connected to the inkrepresenting earth.

Using a digital voltmeter, determine the voltages at points away from the conductorsand hence build up a series of ‘equipotential curves’ from the measurements. Draw theequipotential curves on normal drafting paper or CAD system which already has asketch of the tower.

Once a series of equipotential curves has been found, the electric field patterns maybe drawn orthogonally to the equipotentials.

Hence determine a typical electric field pattern for a 500 kV single-circuit transmissiontower.

NOTE: The equipotentials could also be found using a computer-based finite element analysis package.

16 A multichannel radio transceiver generates individual baseband frequencies using aphase-locked-loop ‘frequency syntheziser’. Sketch a block diagram of a PLL frequencysyntheziser based on the following description.

The system consists of the following sections:

(a) PLL 02A phase-lock-loop IC.

(b) 10.24 MHz reference oscillator.

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(c) 15 MHz offset oscillator.

(d) Voltage-controlled oscillator.

(e) Mixer.

(f) Low-pass filter.

(g) Channel selector switches.

In order to produce a stable high-frequency signal, a phase-locked loop compares theoutput of a reference crystal oscillator with the signal derived form a voltage controlledoscillator. The difference in frequency between the reference signal and the desiredVCO signal is sensed by the PLL which outputs an error voltage in response to thedifference. The error voltage is fed back to a varicap diode in the VCO which changescapacitance in a tuned circuit and adjusts the VCO frequency to that of the reference.

Signals around 15 MHz may be produced with a 10 kHz channel spacing around a PLL02A phase lock loop IC by using a 10.24 MHz crystal reference oscillator. The 10.24MHz signal is fed to a reference input on the PLL 02A which divides the referencesignal by 1024 (10 MHz/1024 = 10 kHz) thus giving the 10 kHz channel step.

A signal from a 15 MHz crystal oscillator is mixed with the output signal from a VCOand the mixer output is passed through a low pass filter and then to the PLL 02A. Themixer produces the sum and difference frequencies between the offset oscillator andthe VCO in its output.

The PLL 02A has a switch selectable binary programmer which enables division of thelow pass filter (LPF) signal before comparison with the reference signal. The channelnumber selected by switches sets the amount of division, e.g. if the LPF signal is1 MHz and Channel 100 is selected, the divided signal will be 1 MHz/100 = 10 kHz.

The signal derived from the low pass filter is fed to the PLL 02A. The binaryprogrammer in the PLL 02A divides the LPF signal by the channel number and theresulting signal is then compared with the divided reference frequency (10 MHz/1024= 10 kHz)and an error voltage is derived (proportional to the difference between theselast two signals both operating at or close to 10 kHz). This voltage is fed back to theVCO which is then pulled to a frequency from which there is no error. A phase lockcondition then exists. In this manner, the output of the VCO may be set to a number offrequencies all separated by 10 kHz. The binary programmer can be set betweenChannel 1 and Channel 512.

On your block diagram, give an example of a signal using ‘Channel 100’ on the binaryprogrammer. This will correspond to a nominal VCO frequency of 16 MHz. The HFsynthesized signal output is taken from the output of the VCO. Show all frequencies inthe diagram.

18 An engineer producing a report on the use of satellite communications produces thesketch in Figure F5. Some information is missing because it is implied. Redraw thisdiagram including the missing information in a form suitable for inclusion in a technicalreport.

Note the organizations are ‘SCPC’ and ‘EC’.

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FIGURE F4 COMPARISON OF COMMON TRANSMISSION LINE TOWERS (EXERCISE 15)

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FIGURE F5 HARDWARE FOR EC SATELLITE SERVICES NETWORK (EXERCISE 18)

19 Some information has been supplied which describes Tumut 3 (T3) power station andthe Lower Tumut switching station (LTSS). Examine the relevant electrical diagrams inFigures F6 and F7 and then answer the following questions.

(a) Choose one feeder (excluding the three feeders to T3) on the diagram of LTSSand explain (in one or two lines) the function of each symbol on that feeder.Ensure that you specify which feeder you are examining.

(b) The drawing contains a symbol that does not exactly conform to theAustralian/New Zealand Standard symbols. Explain why this can be goodpractice. Redraw the feeder up to the busbars according to the Standardsymbols.

(c) On the diagram of T3, explain the purpose of the —, / and \ symbols on the176/88/88 MVA 1 ph transformer.

(d) Explain how the detail on the LTSS and T3 diagrams tie in together given thespecifications of the power station. Add appropriate notes to the diagrams if itwould help the explanation.

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Generators: Six vertical shaft, salient poles, 15.4 kV, semi-umbrella; three are designed to operate as motors after

being started by the turbine. Each generator is rated at 250 MW at 0.95 power factor lagging.

FIGURE F6 ELECTRICAL DIAGRAM OF TUMUT 3 POWER STATION (EXERCISE 19)

Reproduced courtesy of Snowy Mountains Hydro Electric Authority

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FIGURE F7 LOWER TUMUT SWITCHING STATION AND GROUP CONTROL CENTRE

(EXERCISE 19)

Reproduced courtesy of Snowy Mountains Hydro Electric Authority

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20 The circuit diagram of a three-phase system with an unbalanced load is shown inFigure F8. The 6.6 kV line currents are to be determined with the assistance of phasordiagrams. The procedure to determine the currents is as follows:

(a) Draw the phasors of the 6.6 kV voltages.

(b) Draw the phasors of the 3.3 kV voltages noting that Vab is the vector sum ofVa − Vb where Va is the voltage between the low voltage phase ‘a’ winding andthe star point of the secondary windings.

(c) Use Ohm’s law with complex quantities to determine the currents in each leg ofthe delta connected load. Draw the phasors of these currents.

(d) Draw the phasors of the secondary line currents using the relevant loadcurrents and an application of Kirchoff’s Current Law at a node.

(e) Calculate the transformer turns ratio and hence draw the current phasors ineach leg of the high voltage side of the transformer.

(f) Draw the current phasors in the high voltage incoming lines with again, anapplication of Kirchoff’s Current Law.

(g) Write down the magnitude and phase angle of the high voltage line currents asdetermined from the phasors in part (f).

21 In the diagram in Figure C4, the following applies:

+A1 supply

+A2, +A3 not shown

+A4 feed disc motor main circuit

+A5 auxiliary supply

+C control station

+M feed disk motor

Examine the diagram and answer the following:

(a) Does this diagram conform to the current Australian and New ZealandStandards?

(b) Explain how the motor forwards/reverse contactors cannot be closed at thesame time.

(c) In what assembly will wiring terminals 11 and 15 be found?

(d) There are at least 15 pairs of terminal numbered 1–2. Explain why this is so.

(e) Why is the auxiliary supply not drawn up to the auxiliary circuits?

(f) Redraw this circuit WITHOUT discontinuities (i.e. account for +A2 and +A3which are attached to the +A1 supply lines and also have auxiliary circuits in+A5). Incorporate any corrections found in (a).

(g) Draw assemblies as blocks and prepare a wiring diagram.

(h) Prepare a unit connection table.

(i) Why are stop switches often normally closed?

22 Examine the diagram in Figure C7 and answer the following:

(a) How many positions does –S2.1 have?

(b) Why is –S2.1 shown as ON when in position 0?

(c) An operator turns –S2 from position 0 to position 2 FWD. Give a briefdescription of what takes place.

(d) What does –S3 designate?

(e) Explain the supplementary item designation B1 and B2 which appears on anumber of relays and relay contacts.

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FIGURE F8 UNBALANCED LOAD (EXERCISE 20)

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HB3 - Electrical and Electronic Drawing_noPW

Documents

coupled amplifying

boiler feed

slightly wider

coupled amplifying

kirchoffs

international

higher level

te mm cc