Kalpesh's Siemens Report

SIEMENS LTD. AGNEL POLYTECHNIC

CHAPTER:- 1

INTRODUCTION TO SIEMENS

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HISTIRORY OF SIEMENS

It is almost impossible to separate the history of German Industry from

the country’s general political and economic development. One-man stands

pre-eminent among the pioneers of industrial revolution that had began to

transform Germany by the middle of 19th century.

WE RNER VON SIEMENS

JOHANN GEORGE HALSKE

WERNER VON SIEMENS (1816-1892) son of a poor farmer had the courage to

strike into the new territory and shape it scientifically, technically and

industrially. On 1st October 1847, Werner Siemens formed the partnership with

Johann George Halske & his cousin, Johann George Siemens under the name

Siemens & Halske Telegraph Construction Company at Berlin. The initial core

activity of the company was the manufacture of telegraph equipment. The

founder WERNER VON SIEMENS recognized that telegraphy enabled people

to overcome time and distance helping to strengthen international relations and

fostering world economy.

International expansion came about in the 1850’s. Technical successors

soon made the company well known throughout Europe by executing various

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successful projects, like laying Telegraph lines from Baltic Sea and from

Petersburg to Scissile. Siemens soon became an internationally acclaimed

contractor. The company’s British subsidiary, Siemens Halske and Company,

had been founded in West Minister in autumn 1858 to look after company’s

business in Britain and the whole of its empire. In 1865 after the resignation of

Halske the company changed its name to “Siemens Brothers”. In the year 1966

Siemens Schukertwerke AG and Siemens Reineigeerwerke AG [responsible for

all branches of power engineering] was fused with Siemens & Halske AG

[responsible for all branches of communications engineering & instrumentation]

into SIEMENS AKTIEN GESELLSCHAFT (AG). More than 150 countries and

with 240 production facilities outside Germany. Employees worldwide in offices,

factories, laboratories and service organizations total around 373000. All

committed to the highest standard of electrical technology, that Siemens have

been synonym for right from inception. Today’s stay ahead in the field of

electrical and electronics technology, Siemens puts strong electrical and

electronics technology. Siemens puts strong emphasis on Research and

Development with over 48000 employees engaged in this key activity and with

an annual investment of about 10 % of the turn over. On an average Siemens

spends 25 million a day on R & D. Siemens R & D centers are also located

outside Germany, in Europe and the U.S.A.

Siemens experience and strength lie in developing new technologies and

incorporating into its products and systems, which meet the requirement of its

customers. It is one of the pioneers of electrical engineering and has grown as a

result of it. It is in these areas that it concentrates its activities and will continue

to do so in future. Siemens plays a major role in priority sectors like

Telecommunication, Power Generation, Software Transportation,

Modernization, etc.

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HISTORICAL PERSPECTIVE

1857 - SIEMENS was founded in GERMANY.

1867 - SIEMENS first linkage in INDIA.

1954 - Assembly and repair undertaken in a small workshop under

Mahalakshmi Bridge BOMBAY.

1957 - Switchboards manufacture began at Worli Bombay.

1959 - Medical equipment added to the range at Worli.

1960 - Manufacture of Switchgear began at Worli Bombay.

1963 - SWITCHGEAR manufacture at Andheri Chakala.

1966 - First batch of Electric Motors produced at Kalwa.

1967 - Centenary year of SIEMENS associates with INDIA.

1973 - Transfer and expansion of Switchgear production at Kalwa.

1977 - Manufacture of electronic equipment at Worli Bombay.

1984 - Manufacture of Switchboard started at Nashik.

1986 - Manufacture of Railway Signaling products.

1986 - Heavy investment in Tool room and production shop with the

Inception of NC and CNC machine.

1987 - New Industrial Electronics factory at Nasik.

1990 - ‘Sword of Honor’ from British Safety Council.

1991 - New Switchgear factory in Aurangabad.

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1993 - Assembly workshop-Medical products - Goa.

1995 - Launching of Mobile phones.

FUTURE

From the outset, the desire to offer products of optimal technical design and

quality has been a basic rule of the Siemens Group to which all other

considerations are subordinate. To this day, the name of Siemens implies a

guarantee of modern technique, reliability and the highest quality. Siemens in

future would play a vital role in priority sectors like Telecommunications, Power

generation, Software, Transportation, Medical Engineering, Modernization,

Technical Up-gradation. All these priority areas will not only receive technical

and managerial but also financial assistance. The thrust would be on setting up

power plants, software exports and equipment for rolling stocks, equipment,

import high- tech medical facilities. The partner would be both in public and

private sectors, particularly in software areas, which can become an integral

part of Siemens manufacturing activities all over the world.

TRANSPORTATION

TELECOMMUNICATION

POWER GENERATION MODERNIZATION

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SIEMENS IN INDIA

In India, Siemens operates under the following names:

SIEMENS LTD.

SIEMENS TELECOM LTD.

SIEMENS BUSINESS COMMUNICATION SYSTEM LTD.

SIEMENS COMMUNICATION SOFTWARE LTD.

SIEMENS INFORMATION SYSTEM LTD.

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INTRODUCTION TO SIEMENS INDIA SIEMENS was established in India in the year 1922. However, the story of

SIEMENS association with India began in 1867 when WERNER VON

SIEMENS personally supervised the laying of first telegraphic line between

Calcutta and London that historic event initiated a long association making

countries priorities of its own SIEMENS has put its experience and expertise in

major core sectors namely power, industry, transportation, telecommunication

and health care.

It is incredible but true that the first Siemens workshop in India

started in a small space measuring 180-m sq. under the Mahalaxmi Bridge on

1st may 1955. The only tools were available were turret lathe, a drilling

machine, shearing machine and a power saw along with a few portable tools.

Starting with mere strength of 10 people, the first few jobs undertaken included

the repairs of damaged Switchboards, manufacturing of aluminum grill trays,

cable trays, fixing clamps, powerhouse fencing and other fabrication jobs. Most

of the components were imported and some parts were fabricated locally.

Within six months, the manufacturing activities were shifted to the present Worli

Works Complex.

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Though the world has already begun to feel the presence of the leader, it

was not until the early 1954 that India could benefit from this organization.

A policy decision to manufacture indigenously resulted in the formation

“Siemens Engineering & Manufacturing Company of India Pvt. Ltd.” on 2nd

March 1957. On 23rd March 1957, this company entered into a technical

collaboration with Siemens & Halske AG and Siemens Schuchestneske AG

West German (both together now known as Siemens AG). According to this

agreement, the company received manufacturing & patent rights as well as

technical know-how for certain products of world reputed Siemens design. On

28th March 1961, the company became a public limited company under the

name “Siemens India Limited”. Thereafter in 1987, the name was change to

“Siemens Limited”.

From its humble beginnings in India, Siemens Ltd. has become

corporate giant in the last 42 years and has played an active role in the

technological progress experienced in the last four decades. One could say

that Siemens and India have grown together. By making the country’s

priorities own, Siemens had put its experience and expertise in the areas of

national importance. Siemens’ centralized traffic control system ensures safe

and efficient railroad operation. Telecommunication equipment made by

Siemens is used in country’s telephone and telex networks and in medical

engineering Siemens has supplied advance radiological and electromagnetic

system to many hospitals. Besides conventional equipment Siemens now

vides comprehensive instrumentation and control for power stations and

industries.

Siemens India has been consolidating its position over the years. It has

expanded its networks in the form of factories at Worli (Mumbai), Kalwa,

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Nashik, Calcutta, Aurangabad, and Goa. It currently employs around 4000

employees and is backed up by an extensive network of 11 sales offices, 23

representatives, 350 dealers, 6 Factories, 8 offices, 11 Stock points and

system houses are geared to meet the requirements of the customer. “

Siemens India” is the 2nd largest of the manufacturing operations among the

Siemens Companies outside Germany with Brazil being numerous into in this

regard.

Today Siemens India is not just a manufacturing organization.

Manufacturing and designing to Indian Standards and international

specifications is just one part of the task; proper installation, commissioning

and maintenance services are the others. The company grew out of the

nation. India’s rapid strides in the economic and technological fronts would not

have been possible without pragmatic investments in electrical power

generation. Siemens matched the manufacturing program with the country’s

industrial development needs and continued to play a key role in the

industrialization, keeping India in the front line of the international technology.

Siemens provides its technical competence and experience accumulated

from their worldwide operations for their activities in India. In the years to come

Siemens activities will continue to contribute increasingly towards the progress

of India in the economical and industrial fields. Today Siemens involvement in

India reflects the current trends in electrical, telecommunication technology.

SIEMENS hi-tech approach in the field of power Engineering and

Automation System, Medical Engineering and Telecommunication will

continue to provide synergy to co-ordinate efforts to bring India closer to the

frontier of accelerated progress.

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SIEMENS INDIA-INFRA STRUCTURE

SIEMENS INDIA HAS A CURRENT INFRASTRUCTURE OF: 10,000 Employees.

6 Factories.

8 Offices.

11 Stock points.

23 Representatives.

300 Authorized dealers.

6 subsidiary companies.

THE FIVE MANUFACTURING UNITS ARE LOCATED AT:

Mumbai (Worli): Head office

Kalwa (Thane district)

Nashik

Aurangabad

Goa

THE SIEMENS SETUP CONSISTS OF DIVISIONS, REGIONS, WORKS AND HEAD-OFFICES.1. Automation & Drives Division (A&D)

2. Components (CMP)

3. Medical engineering (MED)

4. Switchgear (SGR)

5. Motors, Drives and UPS (MDU)

6. Telecommunication (TSM)

7. Power generation (PGE)

8. Power transmission and distribution system (PTD)

9. Railway and transport system (RTS)

10.Finance and administration (F & A)

11.Personnel (PER)

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SIEMENS IN KALWA

INTRODUCTION TO SIEMENS KALWA WORKS

The Kalwa Planning Department was set up in India to do detail

planning, to feed back information to the planners in Germany and to execute

the plans under the direction of the Works Management of Siemens of India.

The foundation stone of the Kalwa Factory was laid in January 1965 &

within a record 12 months, the Factory was built & machinery installed &

commissioned. Production started in January 1966 of motor. Kalwa achieved

a turnover target of Rs. 9.15 million in its very first full financial year &

continues to perform brilliantly ever since.

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HEART OF MANUFACTURING ACTIVITIES IN INDIA


The Kalwa Factory is equipped with some of the most modern machinery

& testing facilities. It started with the production of Motors & later diversified in

1973 to produce Switchgears & in 1975 to produce Switchboards.

Today, it is the most important Business Center for Siemens India with

almost 40% of the employees of Siemens India working in Kalwa & contributing

almost 45% of the total production of Siemens India. SIEMENS, Kalwa Works

comprises of three manufacturing units viz. The company has been awarded

the ISO 9001 certificate by the international Standards

The Kalwa Complex comprises of 3 manufacturing units and they are

as follows

I. SWITCHGEAR (WSGR).

II. MOTORS (WMOT).

III. SWITCHBOARD (WSWB).

I: - SWITCHGEAR PLANT

At the Switchgear plant, Siemens produces a wide range of Low-Tension

equipments. It comprises of Contactors, BI-metal Relays, Starters, Air Circuit

Breakers, Fuse Switches, HRC Fuses, Motor Protection circuit Breakers, Limit

Switches, and Programmable Switches etc. It also manufactures route-

interlocking relays for Indian Railways.

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THE PRODUCTS OF THE SWITCHGEAR PLANT OF SIEMENS

ARE:-

CONTROL AND LIMIT SWITCHES

STARTERS & CONTACTORS

PUSH BUTTON INDICATORS & SIGNALING EQUIPMENTS

HRC FUSES, FUSE SWITCHES & FUSE BASES

ELECTRONIC TIMER

CIRCUIT BREAKER

BIMETAL THERMAL OVERLOAD RELAYS …ETC

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II: - MOTOR PLANT

SIEMENS Motors are high

quality machines with

economical power

consumption and are

resilient enough to withstand

wide voltage and frequency

fluctuations, a condition

widely prevalent in India. The user-friendly designs are a proof of the fact that

Siemens has a considerable knowledge of the industries using their motors.

Thus Siemens motors have high flexibility in use and less maintenance.

THE VARIOUS PRODUCTS OF MOTOR PLANT:-

DC MOTORS FOR THE FEED DRIVERS OF THE MACHINE TOOL

INDUSTRIES

THREE PHASE SLIP RING INDUCTION

MOTORS.

MULTISPEED MOTORS.

INCREASED SAFETY MOTORS.

SUGAR CENTRIFUGE MOTORS FOR

THE CANE CRUSHING PROCESS.

MOTORS FOR SHIPPING

HIGH TENSION MOTORS UPTO 6.6 KW.

MOTORS FOR MATERIAL HANDLING, CHEMICAL AND STEEL MINING

INDUSTRIES.

THREE PHASE SQUIRREL CAGE MOTOR.

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III: -SWITCHBOARD PLANT

SIEMENS switchboards have established remarkable leadership in the

market. This has through a deep understanding of the customer’s requirement,

resulting in customer oriented products with user friendly design manufactured

with latest technology at par with international std. The switchboard plant

produces range of low tension and high-tension panels, Outdoor Vacuum

Circuit Breakers, Indoor Vacuum Circuit Breakers and Oil Circuit Breakers upto

36 kV. The switchboard is an electrical panel consisting of elements like

potential transformers, current transformers, circuit breakers, timers etc. The

main function of this unit is to act as safety device or power distribution device.

Kalwa works is attached to MVS division. The assembly of various

distributing and controlling and indicating equipment’s at one place situated

centrally is a Switchboard. Basically any Switchboard consists of a switching

device such as Circuit Breaker.

PRODUCTS OF SWITCHBOARDS :-

INDOOR & OUTDOOR VACUUM CIRCUIT BREAKER.

MEDIUM VOLTAGE PANEL.

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MAIN FUNCTIONS OF THE COMPANY

Three manufacturing units in Kalwa have various main functions and have

been very recently reconstructed, orienting towards customers and processes.

These functions are additionally supported by central functions. Some of the

common functions are described below.

TECHNICAL: (PRODUCT DEVELOPMENT)

Preparation of Design Drawings

Laying down Standards and acceptable norms

Assemble and make new designs in Development shop

Testing of new design prototypes or design verifications

Converting German designs into Indian formats

Modify old products to suit new market norms

PROCESS PLANNING: (RESOURCE ENGINEERING)

Planning related to manufacturing methods

Set up manufacturing facilities

Selection of machines, technologies and process based upon the

product design requirements

Designing and ensuring availability of tools, jigs & fixtures

Industrial engineering, fixing time standards, computation of

manpower and capacity requirements

LOGISTICS: (MATERIALS MANAGEMENT)

Receipt & processing of orders placed by sales division

Scheduling - Involving assignments of priorities based on urgency

and material and availability

Procurement and administration of raw materials

Overall co-ordination between marketing, client, excise etc

Management of stores

Dispatch of completed consignments

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MANUFACTURING: Pre-manufacturing - manufacture of components, sub assemblies &

painting of parts

Assembly of manufactured & bought out components

QUALITY ASSURANCE:

Inspection of incoming material

Inspection during stages of manufacturing & assembly processes

Verification of the standard of finished goods

Routine testing after the products are ready

Verify compliance with client requirements

COMMERCIAL:

Product cost calculation

Cost accounting & control

Planning and budgeting

Financial accounting

Inputs for company’s balance sheets

MARKETING:

Sources customers

Studies the requirements of the customers

Collaborates with the technical and manufacturing sections

Markets products made by the factories.

PERSONNEL: Attendance recording and leave.

Wage and salary related administration.

Industrial relation-Maintaining discipline and harmonious relation

with unions.

Personnel planning and development.

Training and development in co-ordination with HRD.

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CHAPTER:-2

INTRODUCTIONTO

SWITCH-GEAR UNIT

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INTRODUCTION TO SWITCH GEARDefinition of Switchgear: -

The control & protection of any electrical system through

a range of electromechanical products like relays, fuses etc is

collectively termed as “switchgear”

Switchgear & Protection

A switchgear product can be said to behave like a conductor during normal

conditions in an electrical system & like an insulator during abnormal conditions.

A switchgear is necessary at every switching point in a power system i.e.

generation, transmission, distribution & actual usage. Between a generating

station and final load point, there are several voltage levels and fault levels.

Hence switching and protective devices have been developed in several forms.

When a fault on any power system occurs, it must be quickly detected and

disconnected from the system otherwise it will spread into the system causing

heavy damage of installation. A switchgear achieves this detection and

disconnection.

Switchgear is a general term covering a wide range of equipment such

as switches, fuses, circuit breakers, relays, contactors, control panels etc.

Besides the supply network, switchgear is necessary in industrial works,

industrial projects, domestic and commercial buildings.

The two functions of switchgear in any power system are:-

To permit plant & distributors (transmission lines) to be conveniently put into

& taken out of service.

To enable the same plant & lines – when these become faulty – to be rapidly

& safely isolated by automatic means.

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In a switchgear system protection becomes necessary against 2 forms of

flowing current

i) Overload current

ii) Short circuit

I. OVERLOAD CURRENT Before discussing specific control components, it is necessary to review

what an overload is and what steps can be taken to limit the damage an overload

can cause. Current flow in a conductor always generates heat due to

resistance. The greater the current flow, the hotter the conductor. Excess heat is

damaging to electrical components. For

that reason, conductors have a rated

continuous current carrying capacity.

Over current protection devices are

used to protect conductors from

excessive current flow. Thermal

overload relays are designed to protect the conductors (windings) in a motor.

These protective devices are designed so that the flow of current in a circuit is at

a safe level to prevent the circuit conductors from overheating.

The National Electrical Code® defines over current as any current in excess

of the rated current of equipment of a

conductor. It may result from overload,

short circuit, or earth fault. An overload

occurs when too many devices are

operated on a single circuit or a piece

of electrical equipment is made to work

harder than it is designed for.

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For example, a motor rated for 10 amperes may draw 20, 30, or more amperes

in an overload condition. In the following illustration a package has become

jammed on a conveyor causing the motor to work harder and draw more

current. Because the motor is drawing more current it heats up. Damage will

occur to the motor in a short time if the problem is not corrected or the circuit is

not shut down by the overload relay.

ii SHORT CIRCUITWhen two bare conductors touch, a short circuit occurs. When a short

circuit occurs, resistance drops to almost zero. Short-circuit current can be

thousands of times higher than normal operating current.

Ohm’s Law demonstrates the relationship of current, voltage, and

resistance. For example, a 240-volt motor with 24 ohms of resistance would

normally draws 10 amps of current. When a short circuit develops,

resistance drops. If resistance drops to 24 milliohms, current will be 10,000

amps. The heat generated by this current will cause extensive damage to

connected equipment and conductors. This dangerous current must be

interrupted immediately when a short circuit occurs.

SIEMENS designed the products keeping the industrial needs in mind. The

optimum design and high degree of quality control of the switchgear makes

them highly dependable and conforming to international standards.

Dependability and durability rectifies all switchgear products such as

contactors, fuse-switches, relays, circuit breakers, starters push buttons, HRC

fuses and limit switches.

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ORGANIZATIONAL STRUCTURE OF WSGR FACTORY1. Personnel Dept : It looks after the human resource development like

maintaining attendance records, wages of employees as well as workers

etc.

2. Tool room : Tool room is a dept that looks after the repairing &

maintenance of the various tools used in the factory at various machines.

It also manufactures new tools.

3. Maintenance : The maintenance dept looks after any electrical fault in

machines or fixtures in the factory.

4. Calibration Lab: As a manufacturing industry, a large number of different

electrical & mechanical instruments are used. It is also necessary for the

instruments to be accurate to maintain accuracy & meet the requirements.

The various instruments are calibrated at the calibration lab, which has

highly equipped machines and standard instruments.

5. Production Cell: The production cell is the complete in charge of the

production of the various products manufactured here.

6. Metal shop: The various metal parts or components that are used in the

assembly of the various products are manufactured at the metal shop.

7. In process: The various parts manufactured at the metal shop are

inspected at the in process inspection dept.

8. Incoming Inspection: Some parts of the products are being brought from

the vendors. The different parts are inspected at the incoming inspection

department before being available for manufacturing.

9. Plastic shop: The various plastic components used for the various

products in the factory are manufactured at the plastic shop.

10. Industrial Engg & Design : Applying MOST at various workplaces.

Designing & organizing the layout of the factory.

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PRODUCT CELL DEPARTMENTORGANISATION OF PRODUCT CELL

In switchgear works production department is split up in to 5 different cells.

And each one is assigned with an assembly of different products as stated in

chapter 3. Each of the cells is called “PRODUCT CELL”. This product cell

office is based on the MILO (Manufacturing Integrated Logistics) principle in

which, Manufacturing process is integrated with logistics, process planning

and scheduling. Each department works as a decentralized one and each

Departmental Head, directly reports to the works manager.

EACH OF THE PRODUCT CELL FURTHER DEALS WITH MANY FUNCTIONS LIKE Logistics

Scheduling

Process Planning

Assembly

House Keeping

PRODUCTION CELLS : -

The products manufactured under different production cell are as follows: -

PC – 1: - Manufacture the small size contactors

PC – 2: - Manufacture the big size contactors

PC – 3: - Manufacture the Bimetal Relays

PC – 4: - Manufacture the Air Circuit Breakers

PC – 5: - Manufacture the push buttons and starters.

These production cells have its own production line set up where the products

are assembled and finished. These departments also concentrate on vendor’s

performances. Product cell departments are accountable for completion of

production and smooth material flow.

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PRODUCT SERIES OF SWITCHGEAR

PRODUCT SERIES

MOLDED CASE CIRCUIT BREAKER 3VL, 3VT

CONTACTORS 3TH, 3TF, 3TB.

AIR CIRCUIT BREAKERS 3WB, 3WL, 3WT

LIMIT SWITCHES 3SE

GUIDE FRAMES 3WN

PUSH BUTTONS & PILOT LAMPS 3SB

STARTERS 3TE, 3TW

ELECTRONIC TIMERS 3RP

BIMETALLIC RELAYS 3UA, 3UW, 3UR

PROGRAM SWITCHES 3LA

DESCRIPTIONS OF VARIOUS PRODUCTS

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CONTACTORSWith the growth of automation and

industrialization in the country, contactors are

being used in large numbers and different

ranges. A contactor is an electromagnetic

device, which makes, breaks and carries rated

current at relevant commands. It is different

from a switch as it protects the system from

overload and other failures by using the respective relay, which is not

possible by a fuse switch unit. Contactors are used in motor control; capacitor

Switching, heating and lighting in single phase and three phase AC as well as

DC circuits.

BIMETAL OVERLOAD RELAYS

The relay is protective device, which is extensively used, in electrical circuits

in conjunction with contactor and

other motor control equipment, they

provide accurate and reliable

protection against overload, single

phasing and overloading due to

locked rotor conditions. The relays

are suitable for frequency operation

up to 15 switching cycles per hour.

When installed individually, relays are unaffected by ambient temperature of

200 C to 550 C.

PUSH BUTTONS & PILOT LAMPS

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Push buttons are basically simple switches

used to make or break certain control systems. Pilot

lamps are devices which indicate the status of the

control circuits i.e., whether ‘on’ or ‘off’.

LIMIT SWITCHES

Limit switches with special contacts are available for

operation at extra low voltage in very dirty and dusty location.

They are used in automatic control circuits where mechanical

position has to be converted into electrical signals for controlling

remote starters, contactors and electromagnetic clutches.

The general working of a limit switch can

be explained with help of the fig. ahead.

Thus a hydraulic actuated cam is operating

the Limit switch. The switch is kept fixed with a

specific reference and the cam is moved linearly

to push the plunger or the roller of the limit switch

to get the desired angle or stroke. This

mechanism is being used frequently used in machines and apparatus where in

the ram motion is guided by the stroke of the Limit switch. Thus Limit switches

form an important part of almost every machine, which are being used in

industries. Actuation of any limit switch must be for at least for 0.1 sec to ensure

that the control command is transmitted.

CIRCUIT BREAKERS

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AS the name implies they are used for making or

breaking circuits. These breakers are used for

putting ‘ON’ or ‘OFF’ the power lines, with

provision for automatic tripping in adverse

conditions like short circuit or overload current,

ground fault or line fault. The operating

mechanisms are designed for a service life up to

100000 make and break operations. Owing to the

short quenching distances, there is only a little arc erosion.

LOW VOLTAGE HRC FUSES

HRC fuses are protective

equipment used in electrical

systems. These are usually used

in conjunction and overload and

single phasing protective relays

for any electrical system. HRC

fuses offer protection to cables,

switchgear, control gear and other apparatus from electromagnetic and

stresses which arise under short circuit conditions. The HRC fuse is widely

used in low voltage system.

L.T. CONTROL SWITCHES

L.T. control switches are used for starting and control of three phase AC

motors. The switches are known for their versatile design, high making and

breaking capacity and long mechanical life.

PROGRAM SWITCHES

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The switches are used for programmed control of machine tools,

switchboards, control boards etc. They can be used in main circuit for direct

control of feeders or motors and in various drives according to the desired

program.

STARTER

A Motor starter has two basic functions to

perform:

1.) Starting and stopping the Motor

2.) Providing adequate protection to Motor and

safeguarding it in event of sustain overloads,

single phasing, locked rotor condition and under

Voltages.

CONTACT BLOCKS

These devices are suitable for installation in any control and

Auxiliary circuit AC/DC. There are separate Models for rear

and front connection. They have high contact reliability,

operator safety, reduced labour input, electronic compatibility

and compactness. They are ideal for panels, control desks, control station and

machine tools etc.

BIMETAL RELAY TIMER

The bimetal relay timer is a modification of the overload relay

unit so as to perform the time delay function. The timer is used

in automatic star-delta starters for changing over connection

from star to delta after the motor has reached the rated speed.

The timer is available with adjustable setting ranges.

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TOGETHER IN A CIRCUIT (WORKING DIAGRAM OF ALL SWITCHGEAR PRODUCTS)

Thus the products namely Relay, Contactor, Motor, Fuse, Switch working together

in a circuit can be explained with the help of the fig as shown below.

The various components are,

1. MOTOR

2. ANKER

3. YOKE

4. COIL

5. CONTACTOR

6. SINGLE PHASE SUPPLY

7. HRC FUSE

8. SWITCH`

9. BI-STRIP

10. RELAY11. THREE-PHASE SUPPLY

WORKING PRINCIPLE

The motor requires three-phase current for it’s working since it is meant for

operating at very high ratings. If this high current is directly supplied to the motor

then at the time of overload current the motor may get damaged due to

excessive current. Thus the motor requires safety, which is provided the

contactor and relay.

The contactor consists of a male electromagnet called ‘ANKER’ and a female

electromagnet called ‘YOKE’. Below the Yoke is a coil which is in a single

phasing circuit with the relay. The relay consists of a NO and a NC contact,

bistrip, rocker-lever mechanism. The single phasing circuit also consists of a fuse

to protect the relay, and a switch for switching ON and OFF the circuit. The three-

phase current

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required to run the motor is first passed through the bistrip of the relay and then

passed on to the motor through the contactor.

Initially when the switch is put ON, the circuit is completed and the current

flows through the NC contact of the relay to the coil. The coil then gets

magnetized and develops electro magnetic flux. Meanwhile the three-phase

current is passed through the bistrips and flows to the contacts of the coil of the

contactor. Due to the flux developed in the coil the yoke gets magnetized and

attracts the Anker towards itself. Thus the three-phase current of the Yoke is

passed on to the Anker and then to the motor.

When overload current passes through the bistrip, the bistrip due to its

physical property bend on overload. Thus the slider on the bistrip is pulled with

the bistrips, which in turn pulls the lever. The lever further pushes the rocker and

due to spring action the rocker is tripped thus converting the NC contact to the

NO contact. Due to this the single phasing circuit is put OFF and the coil gets

demagnetized. Thus no flux is developed and the Yoke also loses its magnetic

property. Still the three-phase current is passing through the bistrip to the

contacts of the coil but the Yoke is not attracted to the Anker and hence current

does not reach the motor.

Thus the motor is being protected from overload current and hence from

damage. Further when the overload current comes to the normal again the bistrip

come back to their normal position and the NO contacts become NC contact.

Thus the single-phase circuit is again completed and the coil develops flux to

attract the Yoke, which in turn attracts the Anker and runs the motor on the three-

phase current from the Yoke.

Thus the relay and the contactor form the main part of the circuit. Since

the three-phase current is passing through the relay directly to protect the relay

an HRC fuse is connected in circuit with the relay, which has a low cut-off

characteristics and thus protects the relay from damage. Thus all the switching

devices cannot go alone and work together in the circuit thus making the circuit

full proof.

- 30 -


Manufacturing process of switchgearThe manufacturing of the switchgear factory is a sophisticated process

combining efficiency, quality & optimum utilization of the machines. The pre-

manufacturing section consists of the metal parts shop, plastic shop, and

galvanic shop, brazing & welding shop & tool room. Components that are critical

in design and dimensions like contacts, magnets, bi-relay components etc are

manufactured in this section.

PRESS SHOP

The metal working presses

(mechanically & hydraulically

operated) installed in the press

shop range from 30 tons up to

125 tons. The raw materials

like copper, brass, phosphor

bronze, and spring steel are received in coil, strip or sheet form and are fed

through pneumatic feeders into press working dies where the final shape of the

part is obtained. This shop also has special processes such as magnet

manufacturing etc. The parts made are either sent for surface treatment,

machining or welding.

MACHINE SHOPThis shop has various machines performing

operations like drilling, tapping, milling,

grinding, and turning of raw materials like

castings or bar stock. Manual operations like

debarring and cleaning are perform after

machining of parts.

- 31 -


WELDING / BRAZING SHOP

This shop has processes such as resistance

brazing for contact joining, manual arc welding for

manufacturing structural items of switchgear. This

process is used for joining two parts of the

contacts. Generally copper and silver parts are

joined at the brazing shop. Contacts of 34-57 contactor ranges are brazed here.

PLASTIC SHOP

Raw materials like

thermoplastic and

thermosetting resin is

molded using the

compression, transfer, or

injection molding

processes to form the final

desired shape of the components. The parts are formed using molding dies

made as per the required shape. Subsequent to molding, processes such as

debarring, belt grinding, and shot blasting are performed for finishing the parts,

which are sent for assembly.

GALVANIC SHOPThis shop deploys processes such as silver, nickel, zinc plating which form the

surface coating on switchgear components as a protective layer against rusting.

Degreasing and pickling of parts is also done here. Efficient water purification

and neutralization plants form an essential part of this process.

- 32 -


ASSEMBLY

This consist of various processes such as riveting, spot welding, soldering

through which various in-house and bought out parts are assembled to form

subgroups which are fed to the main product assembly line after testing. The

final product is assembled in the well lay out and balanced lines. The product

is thoroughly tested and packed before dispatch.

- 33 -


CHAPTER:-3

INTRODUCTION

TO

QUALITY ASSURANCE DEPARTMENT

(QA)

- 34 -


INTRODUCTION TO QUALITY ASSURANCE

DEPARTMENT

Quality is said to be the eye of the manufacturing company. The

need of Quality assurance came into existence due to the principle

“SURVIVAL OF THE BEST”. Since the customers are always in the want of

best & the cheapest product. Quality control in its simplest term is the control

of quality of raw material, during manufacturing of the product (i.e. Optimum

output by using the best process), quality of the finished product. Both Quality

Control & Inspection are used to assure quality. Inspection is the determining

function, which determines materials, supplies parts of finished products, etc.

as acceptable or unacceptable. As the control determines the cause for

variations in the characteristics of products, & gives solution by which these

are to be contracted. It is economical in its purpose, objectives in its

procedures, dynamic in its operation & helpful in its treatment. Coordination

between the quality control groups & other departments such as

Production, Production Planning, & Inspection is of vital importance.

With proper managerial support & co-ordination, the Quality Control

program will be more successful.

ROLE OF QUALITY IN INDUSTRY

The Quality of a product is the 'Degree of Perfection'. Every product is

manufactured according to certain specifications specified by certain common

standards and the industry. The quality of a product depends upon a number

of factors such as dimensions, appearance, etc. To control the quality of the

product, all these factors must be controlled. Quality control is an industrial

management technique by means of which products of uniform acceptable

- 35 -


quality are manufactured. It mainly involves making things right by finding out

causes responsible for the deviations.

A simple way to control the quality is to conduct 100% inspection.

But this procedure is very costly and time-consuming, thus not feasible.

Hence industry uses statistics and this method is known as Statistical Quality

Control. It involves the technique of applying statistical methods based on the

theory of probability to establish quality standards and maintain it.

The main role of quality control involves the following: Quality control is used to set up quality standards.

It involves locating and identifying the process faults in order to control number

of defectives and rejects.

Taking necessary corrective measures to maintain the product quality.

Ensuring that good quality products reach the customer.

Achieving better utilization of raw materials and equipment’s.

QUALITY SYSTEMS IN KALWA WORKS

The Quality Policy is integrated and implemented through an active

involvement of the entire organization. It is ensured that customer

requirements are determined and met, with the aim of enhancing

customer satisfaction. Quality policy of Siemens includes a commitment to

comply with requirements and continually improve the effectiveness of

the Quality management system, and provides a framework for

establishing and reviewing quality objectives.

Quality Objectives stated in Quality Policy.

Commitment to consistent Quality.

Timely Procurement and delivery.

Striving for performance leadership.

Top most priority to Customer needs and Shareholders value.

Employee driven integration and implementation of Quality Policy

in the entire organization.

- 36 -


QUALITY CONTROL & ITS OBJECTIVE:

‘Quality’ means fitness for use at the most economic level. And ‘control’ can be

defined as a process by which we can observe the actual performance and can

compare it with some standard. If there is any, then it is necessary to take

corrective action.

‘Quality Control’ can be defined as operational technique and activities that are

used to fulfill the requirement for quality.

OBJECTIVES OF QUALITY CONTROL

To see that only the uniform & standard quality is allowed to go further.

To suggest methods & ways to prevent the manufacturing difficulties.

To reject the defective goods, so that the products of poor quality may

not reach to the customer.

To find out the points where the controls is breaking down &

investigate the causes of it.

To salvage or rework the rejected goods, if possible.

To improve the companies income by making the product more acceptable

to the customers by providing long life, aesthetic aspects etc.

To improve quality and productivity by process control and customer

feedback.

Judging the conformity of the process to the established standard and taking

suitable action where there is a deviation.

To reduce the companies cost through reduction of loss due to defect(scrap,

rework)

To provide optimum quality at minimum price.

To ensure satisfaction of customers by supplying products of high quality

levels to built customer goodwill.

Developing procedure for good vendor relations.

Developing quality consciousness in the organization

- 37 -


Advantages of Quality Control:

Improved quality of product, which increases the sales.

Scrap, rejection & rework is minimized, thus the cost of manufacturing

reduces.

God quality product improves reputation of the company in the market

& its market share.

Inspection cost reduces to great extent.

Uniformity in quality can be achieved.

.Improvement in manufacturer & customer relations

Improvement in technical knowledge & manufacturing design.

ROLE OF TOP MANAGEMENT WITHIN THE QUALITY MANAGEMENT

SYSTEM

Through leadership and actions, Top management can create an environment

where people are fully involved and in which a Quality Management system can

operate effectively. The quality management principle can be used by top

management as the basic of this role.

1. To establish and maintain the Quality policy and Quality objectives of

the organization.

2. To promote the quality policy and Quality objectives throughout the

organization to increase awareness, motivation and involvement.

3. To insure focus on customer requirements throughout organization.

4. To insure that appropriate processes are implemented to enable

requirements of customers and other interested parties to be fulfilled

and Quality objectives to be achieved .

- 38 -


5. To ensure that an effective and efficient Quality Management system is

implemented, established and maintained to achieve these quality

objectives.

6. To assure the availability of necessary resources.

7. To review the Quality Management system periodically.

8. To decide on actions regarding the Quality policy and Quality objectives.

9. To decide on actions for improvement of the quality management

system.

INSPECTION

Inspection is part of QC. Quality control comprises of the stages as

observation, recording, analyzing and suggest corrective & preventive

actions. Observing is in broader sense deals with inspection procedure.

Definition :- The process of measuring , examining testing , gauging or

otherwise comparing the unit of product with the applicable requirement

Unit of product is the item inspected in order to determine its

classification or to count number of non-confirmations.

OBJECTIVES OF THE INSPECTION PROCEDURE:-

1) Inspection procedure separates out defective and non-defective

components and ensures adequate quality of production.

2) It detects defect in raw material and flows in process that can affect future

machining procedure or final assembly of the product. Thus it eliminated

the problem before they arise.

3) It prevents the further machining operations on defective component so

the operation cost, labour cost etc. are saved.

4) It ensures safe operation of the part in relation to the other parts or

customer needs.

5) It detects sources of weakness and troubles in finished products and thus

checks the work of designer.

6) It improves the relationship with customer by assuring him of good quality.

- 39 -


THE FOLLOWING DEPARMENTS FORMS THE PART OF QUALITY ASSURANCE

INCOMING INSPECTION:

The outsourced components are inspected in this division.

Raw material inspection

Components inspection

A number of physical, chemical & metallurgical test are

conducted to check the quality by the inspectors.

IN PROCESS INSPECTION :

The components internally manufactured and during assembly are inspected in

this division.

The process is carried out in three stages as follows:

Sample inspection:

This is the first stage inspection in which the components being

manufactured initially after the tool change is inspected to confirm the proper

position of the tool and the component manufactured are as per dimension

specified.

- 40 -

QUALITY ASSURANCE

INCOMMING INSPECTION

INPROCESS INSPECTION

FINAL INSPECTION


In process Inspection:

This is the second stage inspection in which the inspection of the

component is regularly carried out at particular interval to see the working of

the tool. This is previously fixed.

Release:

This is the last stage in which after final verification of the

components as per drawing the components are released on to the line for

assembly.

FINAL INSPECTION:

In this inspection procedure the life testing (in millions of life) as

well as packed good audit of the product is carried out. Packed good audit is

to keep a check on the finished product released from the assembly line.

Whether it is according to specification or standard mentioned. Packed good

audit is likewise a very critical operation from quality point of view. Various

steps performed in packed good audit are as follows:

Randomly pick up the quantity of product for audit.

Check the products packing material used for packing.

The number of quantity mentioned on the packing label of the box is

checked for the quantity present inside.

Then the product is removed from the packet and checked for the MFLB,

the CE mark and the execution of the product as per the specification.

If any of the above steps is found faulty I-report for the product is made. This

report is handed over to the Production manager and assembly line incharge

giving them the intimation for sorting out of the whole PD. Only after the sorting

of the whole PD, it is allowed for dispatching.

- 41 -


CALIBRATION DEPARTMENT

The calibration of the switchgear unit is responsible for the calibration of

the instruments used in the shop floor on the machines and for the inspection by

the inspectors. The calibration of various instruments is carried out according to

the calibration due date given by the calibration department.

In case of any instrument being used frequently in the shop, the calibration

department is given the instruction to carry out the calibration that particular

instrument in a short period of time. The department gives a recall list to each

and every department using instruments, at the end of the month.

ROUTINE INSPECTION / TESTING ACTIVITIES OF QA

Product cell in charge will be responsible for regular routine inspection & testing

of switchgear product and component.

1) The inspector & Tester shall do the routine inspection and testing as per the

controlled plan or relevant inspection chart.

2) The releasing / signaling of part delivers shall be done by the respective line

foremen or group leaders authorized by him.

3) The daily inspection details along with the fault codes shall be made

available to QA personnel by the product line incharge. This shall be done

every morning & the records will be of previous working day.

4) Preparation of monthly summary sheet, on the basis of fault diagram of

different products will be done by QA personnel who will convey monthly

along with the respective product incharge to chalk out preventive measures

to minimize / prevent rejection.

5) Ordering / procuring & maintaining of necessary inspection / test instruments

& equipments shall be the responsibility of the respective product incharge.

- 42 -


6) The product incharge are entirely responsible for the outgoing quality of the

product.

7) Planning of facilities / training of people shall be the responsibility of the

product incharges with the help of QA personnel and PD.

8) QA personnel shall inspect / check the testing facility including fixtures &

panels & reports about the healthiness of them to product incharge.

9) Even if the outgoing products / spears do not indicate any visible defects, if

procedures / process are violated, the entire batch may have to be withdrawn

even after party delivery signature.

10) Make good for the damage at sites / clients ends due to manufacturing

defects / quality defects shall be the responsibility of the product group in

charge.

11) Product group incharge shall be responsible initiating and implementing

various corrective measures /actions/improvements process as deemed

necessary from time to time.

12) Scrapping of materials / reworks management & extra cost shall be entirely

being responsibility of the product groups. However monitoring & reporting of

extra cost continues to be a QA function.

13) Calibration of meters gauges & ordering new gauges will be the responsibility

of the product in charges.

14) A year marked place shall be provided in every product line for displaying

the rejection / Fault analysis.

15) A pocket shall be provided in each line for displaying fault diagrams charts.

16) Procurement of new testing schedules shall continue to be provided by

product development department.

17) The control plan shall continue to be made & provided by QA.

- 43 -


DIFFERENT AUDITS CARRIED OUTPRODUCT AUDIT

Here the particular product is taken for audit and studied thoroughly to assure

that all its parameters are according to the design SPECIFICATION. The

reference for audit is the control plan and Inspection & Testing (I & T)

schedule .Apart from these if any point is found noteworthy, it is recorded as

deviation and corrective action is registered under the name of the person

responsible for it. This activity is important because it checks if the products are

manufactured according to the design standards and testing is done according

to the specific control plans or not.

PROCESS AUDITVarious processes on the assembly line are classified as routine and special

process. The special processes are audited after a specific duration. This is to

check if the workers are following the work instructions or not. Similarly any

discrepancy in the process is also noted and acted upon. The reference for this

Process Audit is method instruction sheet.

VENDOR AUDITThe vendors are audited regularly. The nature of the audit is similar to packed

goods audit and process audit. This helps in keeping a check on the quality of

the material supplied by the vendors.

PACKED GOODS AUDIT:This is a daily activity done for all the products .Finally, completely packed

products that are ready for dispatches are audited. Various check points are given

for different products and the audit is done accordingly .If any deviation is found in

the audit, an I-report is prepared and corrective action is implemented.

- 44 -


This activity holds immense importance from the point of view that faulty product

are prevented from going outside the company. It is also steps towards reducing

customer complaints.

The record of packed goods audit report and its I – report in case of deviation is

preserved for a period of six months. The report serves as reference whenever

customer complaints received.

MECHANICAL LIFE TEST LABORATORY:The mechanical life test lab is set up for ensuring the mechanical reliability of

contactors. Here, along with their life their endurance is also tested.

Daily checking is done to ensure the physical & aesthetic appearance of contactor.

The parameters like coil & contacts are checked properly. The erosion of contacts

& burning of coils are taken note of seriously & corrective actions are taken. There

are two modes of testing, continuous & flash mode the contactor is kept on

CONTINUOUSLY, WHEREAS in flash mode the contactor closes & opens

CONTINUOUSLY. There are specifications given as to which contactor is to be

operated at what frequency and what voltage. However there is provision for

changing frequency and voltage if required .The mode of operation can also be

changed.

VDE TESTING LABORATORY:The relays at Siemens undergo various tests, one of which is VDE Testing. Here

relays are mounted on the respective type of contactors. The soldering of

contactor is done so as not to produce flashing action & only continuous flow of

current through them. This test can be carried out in auto mode as well as manual

mode & program is fed to the computer.

There are two type of test being carried out.1) SINGLE PHASE TEST.

2) THREE PHASE TEST.

- 45 -


1) SINGLE PHASE TEST:- This test is done to check the tripping time of the relays when any one phase goes

off. The current progression is as follows:-

1st half hr.:- SOURCE A rated current

SOURCE B 0.9 times the rated current.

2nd half hr.:- SOURCE A 1.15 times rated current.

Source B no current supply.

The relays are supposed to trip within 2nd half hour.

2) THREE PHASE TEST:- The three phase test is carried out to check the tripping time of the relay’s when

over loaded with current PROGRESSION AS follows:-

Rated current for 1st half hour.

5% over load for 2nd half hour.

20% over load for next 10 min.



Relays are supposed to trip within 20% of over load.

- 46 -


MATERIAL FLOW DIAGRAM

- 47 -

NO

YES

NO

MAIN STORE

RELEASED

G.R.N.

SCRAP

INSPECTIONSTAMP

NO

WHETHERURGENT

MFG.

PROCE

SS

MFG.

SHOPINSPECTION ASSEMBLY LINE

PROD. ORDER

ASSEMBLY

INSPECTION & TESTING

RECTIFY

WHETHEROK CAN

BE

RECT

IFY

SCRAP

WHETHEROK

CAN

BE

RECT

IFY

RECTIFY

PACKINGB.D.C

DEALER

CUSTOMER

ORDER

P.C.O

RESERVE MANUFACTURE

STOCK

IMC

REQ.

BOC

REQ.PURCHASE ORDER

MANUFACTURING BY VENDOR

RECEIVING MATERIAL

INCOMING INSPECTION

PROD. ORDER

WHETHEROK

WHETHERSERIOUS

INSPECTIONREPORT

VENDOR

REJECT

DECISION TO BE TAKEN BY QUALITY

MANAGERS

APPROVED

CHALLAN

INSPECTION ACCORDING TO CONTROL PLAN

REJECTIONCHALLAN

YES

NO

YES

YES

YES

YES NO

CUSTOMER


MATERIAL FLOW

The flowchart shows how material flow takes place within the industry.

First of all, the end customer or the dealer, if it is a bulk order, places an order with

the sales office. In other cases, the sales engineer goes on site requesting

customers to place orders with them.

The sales office then contacts the Order Execution Cell (O.E.C) and books

the sales order. At the beginning of each month, the OEC gives Planned

Independent Requirements to the various Product Cells. This PIR is calculated

from the Sales forecast given by the Marketing Department, the Data from the past

and are given for a period of 3 months.

Then, the BDC checks the stock with them. If the required products are in

stock the BDC it to the dealer or the customer. On no stock availability, order is

given to the assembly line.

To manufacture these orders, Internally manufactured components (IMC)

as well as brought out components (BOC) are required. For IMC’s, requirement is

given to the plastic shop and the pre- manufacturing parts shop. For BOC’s,

Purchase order is to be given to the vendor. The material is then send by the

vendor by a challan and is received in the Receiving Department. After the

material is counted, given a location i.e. is kept in a Schaffer box or a cage box, a

Goods Received Note is prepared.

The Quality Inspectors according to the Control plan then inspect the

material. If the material is to the required quality standards it is released and sent

to the stores with the white copy of the GRN stamped and signed by the Inspector.

Posting is then by the incoming inspector and then by the Stores In charge and

- 48 -


given a proper location in the stores. If it is urgent then it is taken on the assembly

line.

If the material is not okay, an Inspection (I) report is made. If serious, a

decision is taken by the Quality managers. A decision is taken whether the

material can be sorted and used or whether it has to be rejected. In the latter case,

a rejection challan is made and material is sent back to the vendor. The same

procedure is followed for the internally manufactured components.

After the material reaches the assembly line, a Production order is made to

produce the required quantity. The assembly of product begins, followed by

inspection and testing. If the tested products are found to be defective, they are

rectified for the given errors. All the finished product are packed and sent to BDC,

which dispatches it to the dealer who, sends it to the customer.

- 49 -


CHAPTER:-4

PRODUCT STUDY – BIMETAL RELAY

- 50 -


BIMETAL OVERLOAD RELAYThese relays operate on the thermal effect of electric current. Generally they do

not measure the temperature directly. Thermal relays sense the current by

temperature rise produced by the current.

The simplest thermal relay used in motor starters overload protection devices

employ a bimetallic strip mounted above a resistance wire. The passage of

excessive current through the coil causes the bimetallic strip to deflect and thereby

close the relay contacts. A system of lever which is to be adjusted with respect to

the compensating strip is arranged to obtain the closer compensation for ambient

temperature usually provided by another bimetallic strip .The bimetallic strip

consists of two metals, which have different coefficients of expansion joined

together.

TYPES OF SIEMENS BIMETAL OVERLOAD RELAYS:-

Relays for contactor mounting .

(1) 3UA50

(2) 3UA52

(3) 3UA55

(4) 3UA58

Relays used in starters.

(1) 3UW50

C.T operated relay.

(1) 3UC66

(2) 3UC62

- 51 -


1). 3UA50/52 RELAYS: The 3UA50/52 relay have two NO (normally open) contacts; namely

NO1 + NO2.

They have one NC (normally closed) contact.

Connections are bent and they have all the four screws for auxiliary

connections.

For bistrip winding both the strip and wire designs are being used.

Hence winding is being done on bistrip winding machine.

They are designed for a number of current ranges ranging from 0.1A

to 25A.

2). 3UW50 RELAY:

The 3UW50 relay has one NO (normally open) contacts.

It has one NC (normally closed) contact.

Connections are straight and it has only two screws for auxiliary

connections.

For bistrip winding both the strip and wire designs are being used.

Hence winding is being done on bistrip winding machine.

It is designed for a number of current ranges ranging from 0.1A to

25A.

It is being used in Raja starters.

3). 3UA55 RELAY:

The 3UA55 relay has two NO (normally open) contacts; namely

NO1+NO2.


- 52 -


Connections are parallel and it has all the four screws for auxiliary

connections.

For bistrip winding both the strip and wire designs and also the

heating strip design are being used. Hence winding is being done on

bistrip winding machine as well as manually.

It is designed for a number of current ranges ranging from 0.1A to

45A.

4). 3UA58 RELAY:

The 3UA58 relay has two NO (normally open) contacts; namely

NO1+NO2.


Connections are larger and are named as ‘Z1’ & ‘ Z2’ connections and

it has all the four screws for auxiliary connections.

For bistrip winding the heating strip design are being used. Hence

winding is being done manually.

It is designed for a number for higher current ranges ranging from

16A to 120A.

3UA58 Relay salient features are visible from the snap.

5). C.T OPERATED RELAYS:

Siemens C.T operated relays provide accurate overload and

accelerated single phasing protection for three phase motors having rated

currents up to 630A/400A. Type 3UC comprises of current tripping unit

which makes use of dual slider principle for faster tripping under single

phasing.

The C.T operated relay consists of a current transformer, which

comes into circuit before the relay. Thus C.T operated relays are being

used in circuits where higher current ranges are required. The primary

- 53 -


coil of the C.T converts the three-phase current to the required range

current of the secondary coil by means of the current transforming ratio.

SALIENT FEATURES OF BIMETAL OVERLOAD RELAYS : -

BUILT IN SINGLE PHASING PROTECTION :

Besides three-phase overload protection, the relays offer a built in

single phasing protection using differential slider principle.

TEMPERATURE COMPENSATION:

The relays are temperature compensated between service

temperatures of –25 degree Celsius to 55 degree Celsius.

OVERLAPPING SETTING RANGES:

For proper selection of overload relays to match the current drawn

by the motors, a number of overlapping ranges are incorporated which

can be adjusted with the help of setting dial provided at the top of the

relay.

SHORT-CIRCUIT PROTECTION:

The relays protect themselves against overload up to 10 times the

maximum setting. Beyond this i.e. in the short circuit zone, the relays

must be protected by a short circuit protection device (HRC fuses).

APPLICATIONS:

3UA5 and 3UA6 are triple pole adjustable bimetal overload

relays with built in single phasing protection. In conjunction with

contactors and other motor control equipment, they provide accurate and

reliable protection to the motors against overloads and single phasing.

They also offer protection against unbalanced voltages.

- 54 -


3UC5 and 3UC6 are triple pole adjustable, saturable C.T operated

bimetal overload relays (with built in single phasing protection feature).

They are ideal for heavy starting applications, when heavy masses are to

be put in motion with the resultant long starting period. In conjunction with

contactors and other motor control equipment, they provide accurate and

reliable protection to the motors; with an acceleration time up to 30 sec

and starting current up to 6 times the rated current, against overload and

single phasing.

The 3UC5/6 relays comprises of three saturable current transformers, a

resistance unit and a special bimetal relay connected to the secondary

winding of the C.T. It is a composite unit with bimetal relay mounted on

the CT’s.

The saturable current transformers linearly transform the current up to

approximately twice the set current but above this value the transformer

core gets saturated and the secondary current is proportionately less.

Thus these relays permit heavy starting conditions of motors and offer

dependable protection against overload.

- 55 -


MOUNTING: Relay types 3UA50, 52, 55, 58 are suitable for mounting on SICOP

power contactors as shown in the snap below.

RELAY

However, a simple accessory is available for converting contactor-

mounting relay to individual mounting as shown in the snap below and

suitable for screw type mounting and DIN RAIL mounting.

PARTS OF A RELAY: Various components used in the Relay and their use:-

1) Scale: - The scale represents the current range of the relay for, which the

relay is designed. It is used for adjusting the relay to the required current setting.

Scale has a cam type arrangement, which moves the compensating strip & thus

moves, the releasing lever. By moving the compensating strip the gap between

the lever and the tension spring increases or decreases.

2) U – clip: - U – Clip is used, which holds the scale in the housing.

- 56 -

CONTACTOR


3) Red Knob: - The red knob is used to test the

tripping of the relay. It actuates the rocker, having a

snap action.

4) Blue Knob: - The blue knob resets the relay once the relay is tripped. Also

these relays have an auto reset function, once the relay is kept on auto-reset

mode it directly resets after tripping. This is one of the most important features of

the 3UA relays.

5) Green Indicator: -

It indicates whether the relay has tripped or not (only when the relay is in

manual resetting condition). It is just for an indication purpose.

6) NO1 Contact Complete: - No1 contact complete comprises of No1 contact,

contact spring 1 & silver rivet. First the silver

rivet is riveted with the contact spring 1 and

then this assembly is again riveted with NO1

contact. This whole assembly forms the NO1

contact complete. This assembly is flared in the housing.

7) NO2 Contact Complete: -No2 contact complete comprises of No2 contact,

contact spring 2 & silver rivet. First the silver rivet

is riveted with the contact spring 2 and then this

assembly is again riveted with NO2 contact. This

whole assembly forms the NO2 contact

complete. This assembly is riveted in the housing.

- 57 -


8) NC Contact: - This contact is also known as Silver contact. This contact is

riveted inside the housing below the NO1 and NO2

contacts. This contact together with bearing

bracket forms the NC contacts. It is mainly a

copper contact, which has silver plating.

9) Bearing Bracket Complete: -

It comprises of bearing bracket, bearing pin, adjusting screw, terminal plate &

connecting wire. First the bearing pin is riveted in the bracket. This bearing pin

engages the compensating strip and releasing lever. Adjusting screw is screwed

inside the bracket. Screw holds the tension spring, which is engaged with rocker.

Terminal plate is spot welded with the use of connecting wire from the bracket.

This terminal plate with the silver contact forms the NC contacts.

10) Rocker Complete: -This is the most important part of relay on, which the

tripping of the relay is dependent. This part

comprises of rocker dolly, insulated piece &

silver rivet. Silver rivet is riveted with rocker

dolly. Then the rocker dolly is inserted inside

insulated piece, both are ultrasonically welded.

Rocker does the snap action while tripping.

11) Tension spring: - The tripping force of the relay is mainly depended on

this spring. So the tension of this spring should be very accurate. Normally the

force is 7.2 N. Tension spring’s one end is engaged in the rocker dolly ant the

other end is with adjusting screw of the bearing bracket.

- 58 -


12) Compensating Strip Complete: - U Clip and Compensation strip

comprise the sub assembly of the compensation strip complete. U clip and

Compensation strip both are spot-welded. Then they are tempered for

releasing stresses, which are developed during spot welding. This strip is used

to compensate the effect of normal atmospheric temperature. Compensation

strip is mounted on the bearing pin of the bearing bracket; in between this the

releasing lever is placed. One thing is kept in mind that the compensating strip

should be free to move.

13) Releasing Lever Complete: - Adjustment lever, adj. Screw & releasing

lever together form the sub assembly of releasing lever complete. Adjustment

screw is screwed in the releasing lever. It is mounted in the u clip of

compensating strip. It should be free to move. Releasing lever complete is

coupled with bistrips with the use of change over lever, which is engaged in the

forward and backward slider. Any movement of the bistrips will in turn move the

releasing lever, which in turn moves the tension spring and the rocker dolly and

the relay is tripped.

14) Slider Assembly: - This slider assembly consists of forward slider,

backward slider and change over lever. As told earlier backward slider is

placed first in the housing than on it, the bistrip assembly. On top forward slider

change over lever is placed and than forward slider is locked in the change

over lever. So bistrips and this lever forms a coupling. Any movement in the

bistrip will result in the corresponding movement in the sliders. These sliders

move the releasing lever and thus the relay is tripped when the bistrips bend.

- 59 -


14) Bistrip Complete: - Bi holder, Bistrip, Resistance strip and Insulating piece

together forms the Bistrip complete. Bistrip is made up of 2 different metals,

which has different co-efficient of expansion. When the current passes through

the bistrip, it gets heated and the bistrip bends. The bending is in the direction

of that metal, which has a low co-efficient of expansion.

First the shunt strip is spot welded on the bistrip (only in some high ranges

to increase the resistance). Than insulation piece is placed over the bistrip.

This assembly is placed in the auto winding m/c, where the winding of strips

and wire is done for different ranges. Here no of turns and pitch are maintained

as specified. One end of wire spot-welded with the bistrip it self. This bistrip

complete is spot welded with the biholder. Backward slider is placed first and

than whole assembly is screwed inside the housing. The other end, which was

left open is TIG welded with the connections. Tempering is done for stress

removal, which is developed during spot and TIG welding. This process is

being used for relays of type

3UA/3UW50, 3UA52 and 3UA55, for 3UA58 the heating strip design is used

which is done by manual folding patterns and then clamped.

- 60 -


OPERATING PRINCIPLE OF BIMETAL RELAY.

The operation of a birelay depends upon the deformation of a bimetallic

strip or coil, which is heated by a current proportional to that in the circuit,

which the relay controls. The strip is composed of two metals having different

coefficients of expansion, & firmly fixed together throughout the length so that

different rates of expansion of the two layers of metals cause the strip to bend

when heated. The strip may get heated by the passage of current through it

directly, or by radiation & convection from another heating element, or by

immersion in an oil bath heated by the operating current.

Overload protection is accomplished with the use of a bimetal strip. This

component consists of a small heater element wired in series with the motor

and a bimetal strip that can be used as a trip lever. Under normal operating

conditions the heat generated by the heater element will be insufficient to

cause the bimetal strip to bend enough to trip the overload relay. As current

rises, heat also rises causing the bimetal strip to bend enough to trip the

overload relay. Some overload relays that are equipped with a bimetal strip are

designed automatically reset the circuit when the bimetal strip has cooled and

reshaped itself, restarting the motor. If the cause of the overload still exists, the

motor will trip again and reset at given intervals. Care must be exercised in the

selection of this type of overload, as repeated cycling will eventually damage

the motor.

- 61 -


THE WORKING OF THE RELAY IS DEPENDENT

UPON THE FOLLOWING FACTORS: -1) Bimetal heater assembly:-

Three bimetals are used, which are spot

welded at one end to one terminal

(connection) of the relay. The other end

is free to move. There are two sliders,

Top slider & Bottom slider. The free end

of the bimetal is inserted between these

two sliders. Strips of Nichrome called heater coils are wound over the bimetal.

Insulation strips separate the bimetal and heaters (to prevent short circuit

conditions). The material of the heater is so selected as to withstand the starting

current as well as the short circuit current.

2) Tripping Mechanism:-

This is the most important and critical mechanism in the relay in which the gaps

between bimetal strips and slider, trip force etc. are to be maintained accurately

to control the trip time variations. The force that develops due to deflection of

bimetal strips is transferred through the differential movement of the slider to

operating lever to open the trip circuit.

3) Auxiliary contact and push buttons

There are two push button ‘test’ push button and ‘reset’ push buttons. One

trip contact is available in the control circuit of the relay. It gives tripping signal

to the contactor coil in abnormal conditions. The electrical life of the relay

depends upon these auxiliary contacts. Auto / manual reset facility is also

provided in the same type of relays.

- 62 -


WORKING PRINCIPLE OF BI-RELAY: -Current dependent thermally delayed overload relays have got three bimetal

strips. The motor current that flows through the heater elements or windings

heats these indirectly. For motor currents above 180 amperes, the secondary

current of a transformer is used to heat up the bi-strips. On one hand this

reduces the losses, while on the other hand it increases the short circuit with

stand capacity.

The following will help in better understanding of working of the relay:

1. As the bimetal strips are heated by the motor current flowing through

the heater windings L1/T1, L2/T2 and L3/T3, the strips bend and the tripping

bar (slider) is moved.

2. The tripping bar operates the tripping lever via the ambient temperature

compensation strip; the ripping lever in turn transfers the force to the spring-

loaded snap action moving contact (Rocker). Prior to the tripping, the NC

contact (95 / 96) is closed and the NO contact (97 / 98) is opened.

3. In the event of an overload the tripping lever pushes the snap action

moving contact so that the NC contact is opened and the NO contact closed.

Mechanical switch position indicator signals tripped state. If the reset selector is

on ‘ Manual reset ‘ position, the snap action moving contacts is pushed beyond

its dead center position (re-closing lock out). After sufficient cooling of the bi-

strips the reset button must be used to push the snap action moving contact

back over its dead center position to reset the relay. If the selector is in the

‘Automatic reset’ position, the NC contact is opened and the NO contact

closed, even through the snap action moving contact is not moved beyond its

dead center position. In this case the moving contact returns to its original

position automatically once the bimetal strip have cooled down.

- 63 -


AMBIENT COMPENSATED OVERLOAD RELAY In certain applications, such as a submersible pump, the motor may be

installed in a location having a constant ambient temperature. The motor

control, along with the overload relay, may be installed in a location with a

varying ambient temperature. The trip point of the overload relay will vary

with the temperature of the surrounding air as well as current flowing through

the motor. This can lead to premature and nuisance tripping.

Ambient compensated overload relays are designed to overcome this

problem. A compensated bimetal strip is used along with a primary bimetal

strip. As the ambient temperature changes, both bimetal strips will bend

equally and the overload relay will not trip the motor. However, current flow

through the motor and the heater element will affect the primary bimetal strip.

In the event of an overload condition the primary bimetal strip will engage the

trip unit. (Refer Diagram)

The tripping mechanism of the bistrips can be well understood with the help

of the following diagram shown below:

FIGURE 1

- 64 -

95

97

98

96

L1

T1

L1

T1

L1

T1

1

2

3 4

5

6


FIGURE 2

When overload current flows through the bistrip and the heating element the

bistrip bend from their normal position and thus the slider (4) is pushed towards

the left which in turn pushes the releasing lever unit (1). The NC contact (95)

now becomes NO. the lever pushes the rocker towards the left. When it

crosses the Dead center the NO contacts (97 & 98) become NC and the blue

knob is tripped i.e. the relay trips. While in production for checking the proper

snapping of the relay the red knob (3) is used for resetting.

- 65 -

L1 T1 L1 T1 L1 T1

959795

96

1

2

3

4

5

6


In this load the relay in self-resetting position. The distance adjustment is then done which can be explained with the

help of the following slides.

Initially the contacts NO1 and NO2 are OFF and the probe is not touching

the NO1 contact

The probe is then slowly moved towards the NO1 contact and as soon as it

touches the contact the red light glows. Then the probe pushes towards the

contact further towards NO2. As soon as NO1 touches NO2 a green light goes

ON. At this point on the setting dial zero is set.

Now the probe is moved in the opposite direction i.e. away from the

NO1 contact. The dial needle rotates. Initially the green light goes OFF as

soon as contact between NO1 and NO2 breaks. Then the probe travels

some distance and as soon as it leaves the NO1 contact the red light goes

- 66 -

PROBECTION ANALYSISits gives the E

NO2NO1

PROBE

NO2NO1

Red


OFF. At this point the reading on the dial gauge is taken which is the

distance between NO1 and NO2.

The tension adjustment done at station 7 can be explained briefly as

below . In this position the relay is in self-resetting position.

The tension adjustment is done at this station, which can be explained

with the help of the slide shown overleaf.

A “Torque-meter (1)” is used to measure the spring tension. The probe of

the torque-meter is made to touch the lever and the meter is rotated with

the help of a hand knob at the top. As soon as the probe touches the lever

a red light goes ON. The lever is then pushed to get the lever tripping force

(LTF) on the torque-meter.

- 67 -

PROBESET ZERO

NO2NO1

Red Green


At this point the red light goes OFF. If the tripping force is not in range

then the screw (4) on the lever is loosened to get the required tripping

force. The levers return force is calculated by releasing the lever. Similarly

the rocker tripping force (RTF) and the rocker return force (RRF) is

calculated with the help of another torque-meter (6) placed at the rocker (5)

end.

After the distance and tension adjustment is done then the relay is

said to be partially complete since the distance and tension are the

important parameters, which are to be adjusted with accuracy without

which the relay won’t function properly and would encounter problems in

tripping while in circuit.

At station 9 the hot tempering of the bistrip is done. In this operation of

tempering, 10 times more current is passed through the bimetallic strips so

that when overload condition occurs bistrips should bend and it should not

break. Without the tempering of the bistrips the relay will not function

- 68 -

1

2

3

4

5

6


properly. In the pre-assembly unit for making bistrip complete unit the

bistrip to bi holder welding and also the spot welding of heating strip to the

bistrip is being done. The part of the bistrip where welding is being done

gets heated and expands such that at molecular level the crystal structure

of the bistrip gets distorted. Due to this process stresses are developed in

the bistrip. To relieve these stresses the tempering process is done in the

assembly line. Here a high current is passed through the bistrip so that it

gets heated throughout and expands evenly and then the bistrip is allowed

to cool slowly so that it comes to the room temperature. Due to this heat

developed the molecules get expanded evenly throughout the bistrip and

on cooling a stable molecular structure is attained.

At station 10 the cold calibration of the bistrips done, which can be

explained briefly as below.

After hot tempering the bistrips are kept for cooling for about 24 hrs.

When they get cooled they do not come back to their normal position and

are also not parallel to each other. In cold calibration fixture there are three

calibrated meters corresponding to the three bistrips. The relay is placed

inside for testing. Then the overlapping needle corresponding to each

bistrip is checked for parallelism and if not parallel then the bistrips are

manually bent with the help of a tool and simultaneously the parallelism is

observed in the meter. After this the “X-value” is checked which can be

understood from the fig shown below. X-value is the distance the master

slide is to be moved after the three green lights corresponding to the three

bistrips glow to push the releasing lever so that changeover of contacts

from NO to NC occurs and the red light glows.

- 69 -


Initially when the master slide is touching the releasing lever the red light

glows. This is due to the releasing lever making the changeover of contacts

from NO to NC. Then the slide is moved in the opposite direction and

observed when all the three indicators corresponding to the bistrips glow.

These three lights should glow within 0-5 reading.

Y-value is the distance between the two probes i.e. the distance between

the probe corresponding to the master slide and the probe corresponding

to the releasing lever.

- 70 -

X-value

NC

RED

NO

Green Green Green


At station 12 the hot checking of the relays done can be explained briefly as

below.

The relays are placed in the panel and current is passed through the

relay twice the value of the lower range of the rated current. The relay

should trip in the specified time range i.e. the tripping time of the relay is

checked. If the tripping does not occur properly then the setting dial is

adjusted and again the hot checking is done.

A small lot of the group of relays is then sent to the quality control department

for V.D.E test.

PRODUCTION LINE OF RELAY

WORK-STATION 1:- ON THIS WORK-STATION FIRST THE LOWER SLIDER IS

INSERTED IN THE HOUSING OF RELAY & THEN THE BISTIPS

ARE FIXED BY APPLYING FORCE. ALSO THE SETTING-DIAL IS

FIXED IN THE HOUSING WITH THE HELP OF U-CLIP PIN.

Input:- Relay Sub-assembly, Forward Slider, Bi-strips and Screws,

Setting Dial, U-Clip

WORK-STATION 2:- DISTANCE ADJUSTMENT

ON THIS WORK-STATION SPECIFIED DISTANCE IS ADJUSTED

BETWEEN THE NO1-NO2 CONTACTS & ALSO BETWEEN ROCKER &

LEVER

Input: Sub-assembled Relay from Work station 1

- 71 -


WORK-STATION 3:- TENSION ADJUSTMENT

ON THIS WORK-STATION THE TENSION OF SPRING IS ADJUSTED.

THE FOLLOWING PARAMETERS ARE ALSO ADJUSTED ON THIS FIXTURE:-

1. ROCKER TRIPPING FORCE & ROCKER RETURN FORCE.

2. LEVER TRIPPING FORCE & LEVER RETURN FORCE.

Input : Distance adjusted Relay from Work station 2

WORK-STATION 4:- CONNECTION PRESSING

ON THIS WORK-STATION THE CONNECTIONS ARE FIXED IN THE HOUSING

OF RELAYS BY APPLYING FORCE.

Input: Tension adjusted Relay from Work station 3, Connections (3x),

Cheese Head Screws (3x)

WORK-STATION 5:- TIG WELDING & TERMINAL SCREWING

ON THIS WORK-STATION TIG WELDING IS CARRIED ON

INORDER TO JOINT CONNECTIONS TO THE BISTRIPS.THE TERMINAL

SCREWING IS ALSO DONE ON THIS WORK-STATION.

Input: Tension adjusted Relay from Work station 4

WORK-STATION 6:- COLD CALIBRATION

ON THIS WORK-STATION ALL THE 3 BISTIPS ARE ARRANGED AT EQUAL

DISTANCES FROM EACH OTHER INORDER TO OBTAIN PROPER BENDING

DURING OPERATION.

INPUT:- TIG welded Relay from Work station 5

- 72 -


WORK-STATION 7:- CHANGE OVER LEVER, BACKWARD SLIDER, AND BACKCOVER FIXINGON THIS WORK-STATION THE CHANGE OVER LEVER, BACKWARD SLIDER

& BACKCOVER ARE FIXED IN RELAY

Input : Cold calibrated Relay from Work station 6, Change over lever,

Backward slider, Back cover, Self tapping screw

WORK-STATION 8:- CUTTING AND BENDINGON THIS WORK-STATION THE CONNECTIONS ARE CUT IN EQUAL LENGTH

BEND AS PER THE SPECIFICATIONS.

Input: Relay from Work station 7.

WORK-STATION 9:- HOT CHECKINGON THIS WORK-STATION SPECIFIED CURRENT IS PASSED THROUGH THE

RELAY & ITS TRRIPING TIME IS CHECKED.

- 73 -


CHAPTER: - 5

FIRST PASS YIELD

- 74 -


INTRODUCTION TO FIRST PASS YIELD

THE CONCEPT: -

In this competitive market, even when it is in recession for any production unit

to get maximum output from minimum input needs best ways to control its cost

on every aspect involved in this manufacturing process. On of the best ways is

to control the cost involved in rework and salvage. Hence this concept of first

pass yield (F.P.Y.) was introduced in Siemens to reduce the rejections and

save cost on rework & scrap involved in it. First pass yield is calculated on the

basis of no of tested products to the no of products passed in the first attempt.

THE NEED & REQUIREMENT: -

As the concept clearly gives the idea of the need of first pass yield it indicates

optimum savings on rework & salvage of every component & product

manufactured or assembled within the manufacturing unit. The basic

requirements for maximum F. P. Y. is better process capability, quality of

material supplied by the vendor well within the tolerances, minimum deviations

of critical dimensions & better control over rejection.

CALCULATION FOR F. P. Y: -

“First pass yield is calculated on the basis of no of tested products to the no of

products passed in the first attempt.” F. P. Y. gives the percentage of products

passed as per the Inspection & Testing (I&T) schedule in the first attempt,

hence its gives the efficiency of the unit.

- 75 -

TOTAL DEFECTIVES

F.P. Y. = 100 - ---------------------------------- X 100

TOTAL TESTED


TARGET: -

To attain the maximum F. P. Y. a certain target is set, on the basis of

average previous months F.P.Y. so that the work is being done accordingly to

reduce the no of rejections. A lot of efforts are being taken to achieve maximum

F.P.Y.

ADVANTAGES OF F.P.Y.: -

The various advantages of obtaining better F. P. Y. are:1) Reduces cost of rework: Extra cost is required in rework of a product or

component after it has been failed in certain test due to a specific reason. The

cost of material and the labor cost involved in it can be saved.

2) Reduces cost of scrap: - The cost involved in the salvage of the product

or component if it has been failed in certain test and cannot be rectified (e.g.:

broken components), this cost can be saved.

3) Ensures timely delivers: - Timely deliveries can be assured if all the

products are passed in the first attempt and no rework is required.

4) Ensures better quality: - Better quality of products can be assured if all

the products pass in certain limits well within the tolerance limits.

5) Reduces rejections: - The main advantage of F. P. Y. is that it reduces

the number of rejections and better Production Control can be achieved.

6) Improves productivity: - The overall advantage of improving the F.P.Y.

is that it improves the overall productivity.

- 76 -


- 77 -

F. P. Y

REDUCES COST OF REWORK:

ENSURES TIMELY DELIVERS

ENSURES BETTER QUALITY

REDUCES REJECTIONS

IMPROVES PRODUCTI VITY


CHAPTER:-6

REJECTION ANALYSIS

- 78 -


“REJECTION ANALYSIS IS A PROCESS IN WHICH REJECTED MATERIALS ARE ANALYSED IN ORDER TO FIND THE CAUSE OF REJECTION AND TO PREVENT IT”

THE MAJOR REJECTIONS IN BIMETAL RELAYS: -

After assembly of every Bimetal relay the tester checks them. The test consists

of series of visual, mechanical and electrical tests. There is a list of possible

faults that can occur in a Bimetal relay and each fault is given a fault code. This

list is called as the fault chart and is issued by the quality assurance

department. Although there are number of possible faults, some faults are

observed consistently and these faults are noted in the record book, which is

checked by an authorized person form the quality assurance department.

LIST OF FAULTS OCCURRING ON THE ASSEMBLY LINE

16.5: Not resetting when dial is 2mm below the bottom limit of the range.

During final inspection the tester sets the setting dial to 2mm below the bottom

limit of the specified current range and then checks for continuity after resetting.

This checking is done just as a precautionary measure so that even if the

customer sets the setting dial 2mm below the specified range by mistake the

relay should still trip and protect the circuit.

REASON OF REJECTION (16.5):1. Cold calibration may not ok

2. Tension adjustment may not be ok

3. Distance adjustment may not be ok.

- 79 -


4. Burn on rocker.

5. Bend in bearing bracket.

7.10: No continuity between NO1 + NO2 and NC

This fault is checked before 16.5. As the name suggest in this fault No

continuity is observed between NO1+NO2 and NC contacts.

REASON OF REJECTION (7.10) :

1. Burr is Top cover indicator or housing.

2. Two-compression spring on Indicator.

3. Improper Tension.

4. Rocker not placed properly.

16.4: Indictor not coming in HR Position/not going in Sticky.

This is a visual test in which the tester just observes whether the

movement of the green indicator. There should be no obstruction to the

movement of the green indicator and the movement should not be sluggish.

The main function of the green indicator is to indicate whether the relay is in trip

or set position.

REASON OF REJECTION (16.4):

1. Burr present in housing, indicator or top cover.

2. Tension adjustment not proper

3. Rocker not placed properly.

6.18: Rocker does not snap

Every time the relay is tripped or reset the rocker snaps i.e. it makes a sound.

This sound indicates that the Distance and Tension adjustment in the relay is

proper.

REASONS OF REJECTION (6.18):

- 80 -


1. Burr present on the rocker.

2. Tension adjustment not within specified range.

1.5: Cover fixing screw Defective / loose

The main function of the cover is to protect all the internal components in

the relay for safety reasons and to protect the relay from dust. The operator

visually checks whether the cover has been screwed properly or whether the

cover is loose.

6.9: Rocker tripping force greater than ’x’ N: -

The tests checks this force manually by pressing the red knob, if the

operator has apply more force for tripping the red knob then he concludes that

this relay is defective.

6.8: Rocker tripping force less than ’y’ N

In this case the relay trips very quickly when the blue knob is pressed.

8.1: Red knob in press position

In this case the red knob does not come back to its original position when it is

pressed


1. Spring tension may be less.

2. Length of red knob may be less.

3. Rocker tripping force and return force not ok.

8.2: Red knob Sticky

In This fault the movement of the red knob is very slow and more force is

required to press it.

- 81 -

0

50

100

150

200

250

300

350

400

A B C D E OTHERSFault code

No

of d

efec

ts

0.0

20.0

40.0

60.0

80.0

100.0

120.0

% R

ejec

tion

No of defectives Cumulative %



1. Burr in red knob.

2. Burr in top cover.

3. Burr in housing.

4. Red knob is damaged.

1.1: Housing broken

In this case either there are cracks on the housing or the housing is broken.

2.5: Scale too loose.

In this case the setting dial moves very easily.


1. U- spring used for holding scale may be broken.

2. U-spring may not be proper or may get deformed.

RECORDING OF DATA: -

Every line has been provided with a record book. The data is recorded in the

following format.

Types

of

Relays

Types of

faults

Total no of

rejected

relays

Total no.

of tested

relays

No. of

relays

passed.

The data from this table is converted into fault chart by a authorized person

from Quality Assurance department. Every line has its fault chart. Fault charts

are made every month. The fault Old charts are maintained by Quality

assurance department as a quality department as a quality document.

- 82 -


CHAPTER: - 7

8 D REPORT&

IMPLEMENTATION OF 5’S PRINCIPLES.

8D METHODOLOGY

- 83 -


DEFINITION;-

The 8D reporting method provides a team-oriented and standardized procedure for

problem analysis.

The 8D Method includes the following steps.

1. Establish a team.

2. describe the problem

3. develop interim containment actions

4. define and verify the root causes

5. select permanent corrective actions

6. implement permanent corrective actions

7. prevent recurrence

8. conclusion

THE 8D REPORT CHECKLIST CONTAIN THE FOLLOWING POINTS

1. Processing team.

2. Description of problem

a) Topic

b) Problem.

c) Statistics

3. Immediate corrective actions

4. Analysis of root causes.

5. Permanent corrective actions.

6. Verification of effectiveness.

7. Preventive actions.

- 84 -


FORMAT OF 8 D-REPORT

- 85 -


IMPLEMENTATION OF 5’S PRINCIPLE

ABOUT 5’S PRINCIPLES….

Thirty years ago researchers started studying the secret of success of

Japanese manufacturing companies. 5S turned out to be the most

impressive "secret" in their observation. Because the factories were so well

organized that abnormal situations were readily apparent to everyone. The

equipments were so clean and well maintained that any problem such as a

loose bolt or leaking oil could be easily seen. This passion of cleanliness

and orderliness became a hallmark of Japanese organizations.

So 5’s is the effective housekeeping technique developed by Japanese

people to create a better working environment and a consistently high

quality process.

The technique is a base for any improvement. Even before you plan the

direction you need to take, one must have to remove obstacles to get a

clear view of the current situation.

It is based upon a simple but an important concept that a neat and clean

factory has higher productivity, and produces fewer defects as well as it is a

much safer place to work.

- 86 -


Advantages of 5S

If tools and materials are conveniently located in uncluttered work areas

Operators spend less time looking for items

This leads to higher workstation efficiency, a fundamental goal in mass

production

A clean and tidy workplace leads to greater well being and increased

motivation

Company image improves

Health and Safety is ensured

Machine maintenance

Quality

Productivity

Lean Manufacturing

Results In A Place Easier To Manage

Smooth Working No Obstruction

No Deviation, No Problems

Time Saving

Quick Retrieval

Accidents & Mistakes Minimized

Increases Space

Creates Workplace Ownership

Foundation Of All Qc Tools

Continuous Quality Improvement

Lean Manufacturing

Kindergarten Of Quality Tools & Techniques

- 87 -


PROBLEMS THAT ARE COMMONLY ENCOUNTERED AT THE

DEPARTMENT:

High absenteeism

High turnover

Demotivated employees

Disordered/ cluttered environment

Mistakes/errors

In order to achieve high levels of quality, safety, and productivity, workers

must have a conducive working environment.

It is a housekeeping technique to enhance productivity and safety.

THE 5S PRINCIPLES:

SEIRI – Organisation/Sort out

SEITON – Orderliness/Systemize

SEISO – The Cleaning/Shining

SEIKETSU – standardize

SHITSUKE - Sustain/Discipline

- 88 -


1. SEIRI – ORGANISATION/SORT OUT

We sorted out the material as notched, bent and the blanks which

have approximately same length. According to that we designed

separate material storage rack for all types of doors, and separate one

for all types of top and bottom blanks. Same technique was used for

back and partition also. These decisions were taken as per frequency

of material to be used.

RED TAG TECHNIQUE:

Give staff red labels

Ask staff to go through every item in the work place

Ask if needed & those that are needed, in what quantity

Not needed - red tag it

Store in the red tag area

For wavering items-

- 89 -


Place the suspected items in the red tag area for one week

Allow the staff to reevaluate the needed items

At the end of week those who need items should be returned

The material which had dents or wrongly bent or had some

dimensional errors used to be red tagged by us and written over it was

“NOT OK”. Most of the time the material from notching department had

defects in it and we had to send it back. All the unnecessary clutter is

removed in the form of scrap. A particular space was defined for the

unwanted material.

2. SEITON- ORDERLINESS

It signifies the simple concept that "Everything has a place and

everything in its place." Neatness focuses on the layout and structure of

the office and workplace. It involves where and how the necessary items are

placed. Obstructions to work flow will be easily identified and removed by

having a clearly defined layout. Safe storage should also be practiced, like

storing heavy items at the bottom. Other than storage, attention must also be

paid to the other aspects of workplace layout. The position and height of the

tools and equipment should enable the worker to maintain good posture for

his comfort while making process movements.

Organise layout of tools and equipment

Designated locations

Use tapes and labels

Ensure everything is available as it is needed and at the “point

of use”.

- 90 -


For maintaining orderliness i.e.; SEITON, various task had to be

undertaken like:-

To ensure position of aisle and storage places clearly marked or not.

Tools classified and stored as per their respective frequency of use.

Ballets kept properly at specified places for use.

Safety equipments were kept right beside the LVD machines like safety

pad for small material.

Floors had to be maintained in good condition and it was ensured that

there were no ups and downs on the aisle as it was difficult for workers to

carry the trolley over it.

3. SEISO - (CLEAN/SHINE)

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Cleanliness of the area is visible to everyone. To maintain a good image of

cleanliness, everyone should be individually responsible for cleaning.

Throwing out things that are unnecessary will uncover areas for inspections.

Discarding unwanted items will make the area clear and uncluttered. Daily

inspection, lubrication and cleaning of equipment are part of preventive

maintenance that will increase efficiency of the machinery. Cleaning must

thus be done daily and inspections can be incorporated to ensure that this is

done religiously. Cleaning should be extended even to areas not usually

obvious, such as the washroom.

To make the work place look better and clean following things were

done:-

A fixed position of trolleys and racks was decided and they were placed

accordingly on their respective places with help of fork lift driver.

The workers were told their responsibilities to keep the workplace clean

like their own home and using this fact, everyday in morning half hour was

spent for cleaning machines, tools, punches, dies and arranging trolleys etc.

Every worker who does the setting has been provided with his own

precision equipments like vernier , ninety degree Allen key etc.

The area of the department is divided into LVD section WELDING

section and MECHANICAL PRESS BRAKE section and all the areas were

kept in neat and proper condition.

4. SEIKETSU - (standardise)

- 92 -


“Seeing is believing”; thus emphasis must be placed on visual

management. Standardized conditions on site must be achieved so that

work can be done quickly. Standardizing the way you process or assemble

the product so that everybody performs the operation the same way. An

essential step in getting Lean.

Standardization of all the necessary things needed to be done:-

Firstly the primary task was to ensure proper application of above three S .

Proper procedures, tasks , schedules needed to be made and carried out.

Continue to assess the use and disposal of items

Regularly audit using checklists and measures of housekeeping

Real challenge was to keep it clean.

We also made the SOP (Standard operating procedure)

of Fume hood and other material also.

5. SHITSUKE- (SUSTAIN / DISCIPLINE)

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Discipline means instilling the ability to do things the way

they are supposed to be done. This involves training and inculcating

good habits and having everyone practise them, thus encouraging

the continuity of good habits. As the final S in the 5-S, it propagates

the 5-S practice by ensuring that the former 4-Ss are carried out

conscientiously. The discipline to maintain the improvements and

continue to improve. Probably the hardest of the five elements. Focus

on maintaining the revisions and continue to improve without slipping

back into old habits. Setting up the 5-S is useless if it is not followed

through, as things will return to being bad if they are not well

maintained. Taking a further step, discipline also includes reviewing

current practices and revising them to keep them relevant. It also

means striving for kaizen, which is the Japanese equivalent for

continuous improvement.

Inoculate courtesy & good habits

Make it a way of life

Part of health and safety

Involve the whole workforce

Develop and keep good habits

Make the workers realize that its good for them only.

Followings can be harnessed form the 5S

- 94 -


1. Neat & Clean Workplace

2. Smooth Working

3. No Obstruction

4. Safety Increases

5. Productivity Improves

6. Quality Improves

7. Wastage Decrease

8. Machine Maintenance

9. Visual Control System

10.Employees Motivated

11.Workstations Become Spacious

- 95 -

Kalpesh's Siemens Report

Documents

2nd half hour

dead center

red light

ensures timely

current ranges

packed goods

single phasing

packed good