Inverter & PLC service and maintenance support by System Engineering Ltd

“Inverter & PLC service and maintenance support by System Engineering Ltd.”

Background:

An inverter is an electrical device that converts direct current (DC) to alternating current (AC); the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits. An inverter is essentially the opposite of a rectifier.Static inverters have no moving parts and are used in a wide range of applications, from small switching power supplies in computers, to large electric utility high-voltage direct current applications that transport bulk power. Inverters are commonly used to supply AC power from DC sources such as solar panels or batteries.The electrical inverter is a high-power electronic oscillator. It is so named because early mechanical AC to DC converters was made to work in reverse, and thus was "inverted", to convert DC to AC.

Application:1.1 DC power source utilization 1.2 Uninterruptible power supplies 1.3 Induction heating 1.4 HVDC power transmission 1.5 Variable-frequency drives 1.6 Electric vehicle drives 1.7 Air conditioning 1.8 The general case 1.9 Warnings

In this report contains only the variable frequency inverter or drive. A variable-frequency drive controls the operating speed of an AC motor by controlling the frequency and voltage of the power supplied to the motor. An inverter provides the controlled power. In most cases, the variable-frequency drive includes a rectifier so that DC power for the inverter can be provided from main AC power. Since an inverter is the key component, variable-frequency drives are sometimes called inverter drives or just inverters.

A PLC (Programmable Logic Controller) is a device that was invented to replace the necessary sequential relay circuits for machine control. The PLC works by looking at its inputs and depending upon their state, turning on/off its outputs. The user enters a program, usually via software, that gives the desired results. A programmable logic controller is currently defined by National

Electrical Manufacturers Association of America as a digital electronic device that uses a programmable memory to store instruction to implement specific functions such as logic, sequence, timing, counting and arithmetic to control machines and processes. At beginning of its invention and application (during 1980’s) it was the replacement of conventional sequence system such as electromechanical relays, timers, counters and so on. But now a day it is using for automation of equipment as well as for automation of industrial plant as a whole, monitoring and control of all process variables, data acquisition and analysis, production monitoring and forecasting, trouble shooting of equipment and so on.

Broad Objective:The broad objectives of this report are mainly understood the servicing and maintenance of Variable frequency inverter and PLC.

Specific Objectives:

In order to the broad objectives I have to find out the following objectives. They are as follows:

1. Study on Variable frequency inverter and PLC. 2. Identifying different types of Variable frequency inverter and PLC.3. Suggest probable solution of the identified problem.

Methodology:

Both primary and secondary data are being collected for the purpose of this report. The report is concentrated of the technical support service and maintenance of variable frequency inverter and PLC.

Primary Data are collected from the maintenance Chart, the User Manual handbooks and Text books.

Secondary data are being collected from the printed Journals, brochures and websites.

Limitations:

Sometimes operator trying to repair it but they are not efficient. So machine breakdown time increasing. Though the workers are experienced and efficient, there is lack of monitoring personnel. It would be better to appoint few more personnel of respective fields. Discipline among the workers is not well established. In the marketing section semi finished products and finished products should be minimized. I found few people are applied to tear down

excess outer carton during packing a batch. So care should be taken or there should be an option of immediate delivery of packing materials when needed.

1.1 Background:

System Engineering Ltd is one of the most reputed organizations in Bangladesh kind of for different Industrial Automation works, Electro-Mechanical & Electrical Engineering works, Plant Election & maintenance, Man-Machine Customization etc. Its objective is to help to make maximum return from the system. It has self-supported expertise technical teams with modern tools & technology.

System Engineering Ltd is authorized sole-agent of some world-class manufacturers in Bangladesh. SEL has selected these companies for their high quality products with justified price for Bangladesh. SEL thinks, high quality products & services are the most important factors to our industrial sector for developing our country.

Our outlook is totally different. We were born differently. We are growing with a different view. We are stuffed with courteous, responsive, dependable professionals, who are able to provide a variety of services.

The company enjoys good reputation due to its quality product sales and after sales services, innovation, productivity and customer support. The company is looking forward to providing with efficient customer service, support and better technology to the local market.

1.2 List of Services: Plant Erection & Maintenance Trouble Shooting & Up gradation of Industrial Machinery Man-Machine Customization Electrical LT Panel, MCC Panel, PFI Panel Fabrication Pipe-Line and Cable Work Duct Fabrication

List of products:

PLC LS Korea ABB Finland

Touch Screen & XGT Panel LS– Korea ABB–Finland

Electric Motor ABB – India

Name of Organization System Engineering Ltd Hyundai – KoreaYear of Establishment 2000

Earlier/Old Name System Automation (Till 2007)

Type of Business Plant Erection on turnkey basic Selling of Automation Products

Selling of Low & Medium Voltage Products

Partnerships Distributor of LS, Korea (Old name of LG) for automation products Channel Partner of ABB, Finland for Inverter, PLC, Electric Motor and Instruments Sole-Agent of Autonics, Korea for Sensor and Controllers Exclusive distributor of Hyundai, Korea for low and medium volt electric products

Employees 63 employeesAddress House # 53, Road # 03,

Sector # 3, Uttara, Dhaka – 1230

House # 15, Road # 18, Sector # 3, Uttara, Dhaka – 1230

E-mail [email protected]; [email protected]

1.4 History

Year Activities2000 Three dynamic engineers formed a company named System Automation for

Plant Erection, Maintenance & Trouble Shooting.2001 Joined with LG as Local Distributor in Bangladesh at Sep’2001 for their

industrial automation products.2003 Successfully completed our first plant erection project on Battery

Manufacturing Plant of Rahimafrooz, Zirani Bazar, Savar, Dhaka which they started at 2001 and capacity was 1,50,000 battery/month.

2004 Joined with Autonics Corporation as their Sole-Agent in Bangladesh.2006 Successfully completed plant erection of Global Dyeing & Spinning Mills

Ltd at Rupgonj, Narayangonj.2007 Became a Limited company and changed its name to “System Engineering

Ltd”.2007 Joined with Hyundai as their Exclusive Distributor in Bangladesh for their

LV & MV products.2008 Joined with ABB as their Channel Partner in Bangladesh for their Inverter,

PLC, Electric Motor and Instruments.2008 Started Battery Manufacturing Plant erection project of Rahimafrooz

(10,00,000 battery/month) at Iswordi EPZ (running).2008 Started erection project of Battery Accumulator Plant of Rahimafrooz at

Saver (running).

1.6 Vision

The vision of system Engineering Ltd is to become the country leader for industrial solutions and establish ourselves as the largest and most lucrative service provides in our country.

1.7 Mission

System Engineering Ltd. has acknowledged the responsibility to eradicate the deficit in country’s industrial automation equipment service and to improve the quality of the lives of their employees and the communities they serve. The company aims to achieve this mission not only through best quality products but also through excellence in service.

1.7 Theme

System Engineering Ltd. Always said as their theme “Best service way of progress”. They also use this theme beside their logo.

1.8 Quality Commitment System Engineering Ltd .has acknowledged the responsibility to eradicate the deficit in country’s Industrial automation equipment Industrial automation

equipment and to improve the quality of the lives of their employees and the communities they serve. The company aims to achieve this mission not only through best quality products but also through excellence in its service.The goal of System Engineering Ltd. is to become best electro-mechanical firm in Asia by achieving excellence in all facets of its activities. System Engineering Ltd. believe that with strong dedication, their continued research on quality control and their commitment to ‘Just in Time’ delivery and quality after sales support will certainly lead them to our goal. Their various quality policies involve employing fully qualified experienced engineers some are foreign trained, carrying on regular inspection of their equipments by both local and foreign renowned experts, providing full time training to their newly recruited employees and sharing their ideas. System Engineering Ltd. emphasize greatly on after sales care. With a 12-member team of experienced teams and graduate engineers in charge of support and service department are available even during non working hours, System Engineering Ltd. believe that they serve the customers with the best quality commitment System Engineering Ltd. is proud to declare that their quality management system is better then others company.

1.9 Uncompromising Integrity

Reputation of System Engineering Ltd. is based upon their ability to fulfill promises to shareholders, customers and employees. They do so by being honest in their dealings, taking responsibility and being accountable for their actions. System Engineering treats everyone the way they would like to be treated. They are proactive in identifying issues and coming up with solutions. They ensure that the highest ethical standards guide in making decisions. System Engineering is true to our word.

1.10 Respect & Care for Others

By working as one team with shared goals System Engineering Ltd. achieve great things. They value ideas and contributions from everyone. System Engineering recognize, respect and value diversity in the team. They develop strong bonds by communicating and sharing knowledge. They encourage open discussion and commit to an agreed position.

System Engineering Ltd. has implemented a Quality Management System that is continuously maintained for effectiveness and process improvements in accordance with the requirements of clients.

2.1 The Process Approach

In accordance with the requirements of the standard, EEL has adopted a process approach in design of quality management system. The processes as applicable and relevant to EEL has been identified and defined. Output of every process is input to one or more processes. In case the output is not flowing to any internal of the processes, it flows to customers and other interested parties. Thus input to every process is outcome of one or more processes. In case input is not being derived from any internal process, the same flows from customers and other interested parties or from external sources. Methods have been defined to ensure that operation and control of these processes are effective and efficient. Resource requirements for each of the processes are assessed by management to ensure that operation and monitoring of the process can be done as planned. Strong monitoring, measurement and analysis of the process has been defined as a support process to ensure process performance and is measured and communicated at regular intervals within the organization. Based on the results, action plans are developed for implementing actions necessary for improvement of the processes. 2.2 Product Realization Processes:

1. Order Bagging (Institutional) 2. Forecasting3. Planning4. Product Development5. Procurement6. Manufacturing7. Dispatch & Installation8. Maintenance9. Customer Complaint Handling

2.3 Measurement, Analysis and Improvement Processes: Measurement and Monitoring Customer Satisfaction Measurement

2.4 Top Management Process:Management Review

Chairman

Figure: Organization overview

2.5 Sequence and Interaction ProcessProduct Realization Processes:

Director

General Manager

Utility ManagerMarketing ManagerPlant ManagerProject Manager

EngineerEngineer

Store KeeperMarketing Ast. ManagerLead ManagerLead Manager

Area Managerg

Store Keeper Helper

Ast. Engineer Ast. Engineer Sells man

Head Technician Head Technician

Technician Technician

Past Years Performance Results From other External Sources

Chapter One

Planning Process

Procurement Process

Manufacturing Process

Customer Complaint Handling

Customer

Management Review

Training

Order Bagging (Institutional)

Customer

Maintenance

Forecasting

Customer Satisfaction Measurement

Product Development

Dispatch and Installation

1.1

What is a PLC?

• A digital computer used for automation of industrial processes

• PLC is designed for multiple inputs and output arrangements

• Programs to control machine operation• PLC is an example of a real time system• Armored for severe conditions compared to PC’s• Relay logic replacement• Process Inputs and Outputs

Introduction

• Bedford Associates, founded by Richard Morley introduced the first Programmable Logic Controller in 1968

• PLC was known as the Modular Digital Controller from which the MODICON company derived its name

• Programmable Logic Controllers were developed to provide a replacement for large relay based control panels

• These systems were inflexible requiring major rewiring or replacement whenever the control sequence was to be changed

1.2 Block diagram of PLC :

Master K Series of LG

Reference LG Manual book.

Hardware Configuration of PLC

12Fig.1 Hardware Configuration of a Typical PLC

PLC - Introduction

Fig-2: Bolck diagram of PLC

Inputs

Outputs & Power Supply

Com

mun

icat

ion

Ports

(RS

-485

)PLC - Introduction

Fig-3: Input and Output of PLC

PLC - Introduction

Structure of a PLC

Fig-4: Structure of PLC

The PLC processor

PLC - Introduction

Fig-5: PLC Processor

PLC Input/Output Devices

PLC - Introduction

Fig-6: PLC I/O Port

1.3 PLC I/O Configuration

I/O Configurations

1.4 PLC I/O Configuration

I/O Configurations

Figure of PLC module

I/O Configurations

Power Supply

I/O Section

I/O Section

1.5 Programming Device

Programming Device

Programming Device

Programming Device

Programming Device

PLC size classification

1.6 Advantage of a PLC Control System

Advantage of a PLC Control System

Fig-7:Ladder diagram



Fig-9: Electro magnetic relay


Fig-9: PLC Communication system


Fig-10: PLC machine control system

1.7 Difference from a pc

• A computer is optimized for calculation and display tasks

• A computer is programmed by specialists• A PLC is designed for (logic) control and

regulation tasks• A PLC is programmed by non-specialists• A PLC is well adapted to industrial

environment

Difference from a PC

PLC a Real World Relay Replacement

Real world Parts:• Switch• Bell• Relay

Switch controlling AC circuit or bell

Relay


Relay Coil Symbol

Relay Normally open Contact

Symbol

PLC Input Symbol

PLC Output Symbol

Fig-11: PLC


Real world Parts:• Switch• Bell• Relay

Switch controlling AC circuit or bell

Relay

Example of a Motor Control

STARTSTOP

output

START STOP

output

EQUIVALENT DIAGRAMS

Normally Open Contact

NormallyClosed Contact

1.8 PLC Programming

How to program PLCs?

• Using a specialized Ladder Logic Software– Allen-Bradley uses RsLogix 500 software to program

SLC, Micrologix and so on

– Omron uses Cx Programmer software for its SYSMAC PLCs

– Lg uses KGL_WIN programming software for its Master K-series PLCs

• Other manufacturers has their own software

Ladder Logic

• Ladder logic is a method of drawing electrical logic schematics

• A graphical language popular for PLCs Controllers

• Invented to describe logic made from relays• Language resemble ladders, with two vertical

"rails" and a series of horizontal "rungs" between them

• Rule-based language, rather than a procedural language

• Executed sequentially by software, in a loop

Examples

Relay Logic

Ladder Logic

Examples

• Switch turns on a solenoid for 5 seconds and then turn it off regardless of how long the switch is on for– Use an external timer

• What happens if decided to add 2 or more timers and counters?– Will need a lot of external components and rewiring

• Using a PLC simply program your timers and counters

PLC Signal Process

• Inputs: describe the status of the process to the controller (external)

• States: discrete modes the controller can be in (internal)

• State transitions: functions of the current state and the inputs

• Outputs: actions initiated by the controller based on the current state (external)

1.9 Symbol of ladder logic

Contact/Connection Instructions of LG PLC

Timer Instructions of LG PLC

1.10 Process of programming

Introduction with KGL_WIN windows

1.11 Control panel with a PLC controller

with invention of programmable controllers, much has changed in how an process control system is designed. Many advantages appeared. Typical example of control panel with a PLC controller is given in the following picture.

Fig-12: PLC Control System Panel Board.

1.12 Advantages of control panel that is based on a PLC controller can be presented in few basic points:

Compared to a conventional process control system, number of wires needed for connections is reduced by 80% Consumption is greatly reduced because a PLC consumes less than a bunch of relays Diagnostic functions of a PLC controller allow for fast and easy error detection.

Change in operating sequence or application of a PLC controller to a different operating process can easily be accomplished by replacing a program through a console or using a PC software (not requiring changes in wiring, unless addition of some input or output device is required).

Needs fewer spare parts

http://www.mikroe.com/en/books/plcbook/chapter1/chapter1.htm#1.2%231.2

It is much cheaper compared to a conventional system, especially in cases where a large number of I/O instruments are needed and when operational functions are complex.Reliability of a PLC is greater than that of an electro-mechanical relay or a timer.PLC CommunicationA: It depends on the two devices being connected, whether they are DTE or DCE devices, how they are connected together before adding a RS-232/RS-422 Converter, how many signal lines are required. This information is for devices requiring only Receive (Rx) and Transmit (Tx) signal only, other devices require more connection pairs.A1: CASE #1: The Device connects directly to the serial port on the Computer. The computer serial port is configured as a DTE port, the device cabling is configured as DCE to connect directly. With this connection, the first RS-422 converter connects with a Standard serial cable wired pin #1 to #1, #2 to #2, etc. The second converter requires a null modem connection between it and the device, since our converter is configured as DCE on the RS-232 side, and the device cabling is also DCE. See the connection diagram for CASE #1.

Fig-13: PLC CommunicationA2: CASE #2: The Device connects through a Null Modem (Crossover) Cable to the serial port on the Computer. This original connection requires a Null Modem cable because both Computer and Device are configured as DTE. In this case, the first RS-422 Converter connects to the Computer with a Standard serial cable wired pin #1 to #1, #2 to #2, etc. The original Null Modem Cable is set aside, not used. A new Standard serial Cable is connected to the device and the second converter. See the connection diagram for CASE #2.

A3: CASE #3: In the third case, we want to extend a set of RS-232 connections between two devices, but we don't know how either port is configured. Both devices use DB9F (female) connectors. We have a voltmeter. We know the converters are DCE devices. When powered, the RS-232 output will have a negative DC voltage compared to GND. So, we connect a Standard cable to the device, power it up, measure between Pin #5 of the cable to Pin #3. If it has a minus voltage (usually between -3VDC to -11VDC), connect it to the DB9 connector of the converter. This connection should be okay. If almost no voltage on Pin #3, check Pin #2. If it has the minus voltage, use a Null Modem Connection between the device and converter to swap the pin connections. If neither has a voltage, you need pinouts for the connector/cable. Make a similar test for the RS-232 connections at the other end. The voltage should be on the cable pin connecting to Pin #3. No Connection diagram for CASE #3, it will either match CASE #1 or CASE #2, but could instead require connections with Null Modem Connections on both converters if the original cable is not used.The pin numbers for the RS-422 connections are not shown, they may vary according to the model, but the signal name will be shown on the data sheet.In the case of DB25 RS-232 connections, Pin #2 is TD, Pin #3 is RD, and Pin #7 is GND.Note: These connection figures do not show power supplies or handshaking lines needed to power "port powered" converters. The port powered devices usually need the RTS line and DTR line high (signal level +11 VDC), a power supply may be required for both ends if the RS-422 transmitter voltage is less

than 4.4 volts TD(B) to TD(A). For pin outs of RS-232, refer to the FAQ on RS-232 Connections that WORK!RS-232 FactsRS-232 is a point-to-point serial communications standard that defines the electrical and mechanical details of the interface between Data Terminal Equipment (DTE) and Data Communications Equipment (DCE). Compared with newer standards RS-232 is limited in terms of data rate, maximum distance and noise immunity. The standard defines 25 electrical connections including data lines, control (hardware handshake) lines, timing lines and special secondary function lines. In typical applications many of these lines are not used.Cables: When connecting a DTE to a DCE all connections are straight through. When connecting a DTE to a DTE a special ‘null modem’ or crossover cable is required.Connectors: The original RS-232 connector was a DB-25, which supported all RS-232 lines. Often, DB-9 connectors are used, which support the most common data and hardware handshake lines.Speed/Distance: The standard suggests RS-232 can operate at about 20 kbps over distances of 50 feet, a conservative estimate depending on grounding and noise considerations. Over short distances RS-232 is sometimes operated at rates as high as 115.2 kbps. Several hundred feet is possible at data rates of 9600 bps or lower.Tech Tip: For longer distances, higher speeds and more noise immunity, convert to RS-422 for point-to-point, or RS-485 for multi-drop applications.

PORT POWEREDSERIAL RS232 TO RS485

DB9-Female To DB9-Male or Terminal

PORT POWERED - OPTO-ISOLATED3-WIRE RS232 REPEATER

DB9-Female to DB9-Male or TerminalRS232 serial cable layout

Almost nothing in computer interfacing is more confusing than selecting the right RS232 serial cable. These pages are intended to provide information about the most common serial RS232 cables in normal computer use, or in more common language "How do I connect devices and computers using RS232?" RS232 serial connector pin assignment

The RS232 connector was originally developed to use 25 pins. In this DB25 connector pin out provisions were made for a secondary serial RS232 communication channel. In practice, only one serial communication channel with accompanying handshaking is present. Only very few computers have been manufactured where both serial RS232 channels are implemented. Examples of this are the Sun SPARCstation 10 and 20 models and the Dec Alpha Multia. Also on a number of Telebit modem models the secondary channel is present. It can be used to query the modem status while the modem is on-line and busy communicating. On personal computers, the smaller DB9 version is more commonly used today. The diagrams show the signals common to both connector types in black.

The defined pins only present on the larger connector are shown in red. Note, that the protective ground is assigned to a pin at the large connector where the connector outside is used for that purpose with the DB9 connector version. The pin out is also shown for the DEC modified modular jack. This type of connector has been used on systems built by Digital Equipment Corporation; in the early day’s one of the leaders in the mainframe world. Although this serial interface is differential (the receive and transmit have their own floating ground level which is not the case with regular RS232) it is possible to connect RS232 compatible devices with this interface because the voltage levels of the bit streams are in the same range. Where the definition of RS232 focused on the connection of DTE, data terminal equipment (computers, printers, etc.) with DCE, data communication equipment (modems), MMJ was primarily defined for the connection of two DTE's directly.

RS232 DB9 pinout

DEC MMJ pinout

RS232 DB25 pinout

RS232 DB25 to DB9 converterThe original pinout for RS232 was developed for a 25 pins sub D connector. Since the introduction of the smaller serial port on the IBM-AT, 9 pins RS232 connectors are commonly used. In mixed applications, a 9 to 25 pins converter can be used to connect connectors of different sizes. As most of the computers are equipped with the DB9 serial port version, all wiring examples on this website will use that connector as a default. If you want to use the example with a DB25, simply replace the pin numbers of the connector according to the conversion table below. RS232 DB9 to DB25 converter

DB9 - DB25 conversionDB9 DB25 Function1 8 Data carrier detect2 3 Receive data3 2 Transmit data4 20 Data terminal ready5 7 Signal ground6 6 Data set ready7 4 Request to send8 5 Clear to send9 22 Ring indicator

RS232 serial loopback test plugsThe following RS232 connectors can be used to test a serial port on your computer. The data and handshake lines have been linked. In this way all data will be sent back immediately. The PC controls its own handshaking. The first test plug can be used to check the function of the RS232 serial port with standard terminal software. The second version can be used to test the full functionality of the RS232 serial port with Norton Diagnostics or CheckIt.

DB9 DB25 Function

1 + 4 + 6 6 + 8 + 20 DTR CD + DSR2 + 3 2 + 3 Tx Rx7 + 8 4 + 5 RTS CTS

Testing occurs in a few steps. Data is sent on the Tx line and the received information on the Rx input is then compared with the original data. The signal level on the DTR and RTS lines is also controlled by the test software and the attached inputs are read back in the software to see if these signal levels are properly returned. The second RS232 test plug has the advantage that the ring-indicator RI input line can also be tested. This input is used by modems to signal an incoming call to the attached computer. RS232 null modem cablesThe easiest way to connect two PC's is using an RS232 null modem cable. The only problem is the large variety of RS232 null modem cables available. For simple connections, a three line RS232 cable connecting the signal ground and receive and transmit lines is sufficient. Depending of the software used, some sort of handshaking may however be necessary. Use the RS232 null modem selection table to find the right null modem cable for each purpose. For a Windows 95/98/ME Direct Cable Connection, the RS232 null modem cable with loop back handshaking is a good choice. RS232 null modem cables with handshaking can be defined in numerous ways, with loopback handshaking to each PC, or complete handshaking between the two systems. The most common null modem cable types are shown here. Simple RS232 null modem without handshaking (Null modem explanation)

Connector 1 Connector 2 Function

http://www.lammertbies.nl/comm/info/RS-232_null_modem.html#noha

2 3 Rx Tx3 2 Tx Rx5 5 Signal ground

RS232 null modem with loop back handshaking (Null modem explanation)

Connector 1 Connector 2 Function2 3 Rx Tx3 2 Tx Rx5 5 Signal ground1 + 4 + 6 - DTR CD + DSR- 1 + 4 + 6 DTR CD + DSR7 + 8 - RTS CTS- 7 + 8 RTS CTS

RS232 null modem with partial handshaking (Null modem explanation)

Connector 1 Connector 2 Function

1 7 + 8 RTS2

CTS2 + CD1

2 3 Rx Tx3 2 Tx Rx4 6 DTR DSR5 5 Signal ground6 4 DSR DTR

7 + 8 1 RTS1

CTS1 + CD2

RS232 null modem with full handshaking (Null modem explanation)

http://www.lammertbies.nl/comm/info/RS-232_null_modem.html#loop

http://www.lammertbies.nl/comm/info/RS-232_null_modem.html#full

Connector 1 Connector 2 Function2 3 Rx Tx3 2 Tx Rx4 6 DTR DSR5 5 Signal ground6 4 DSR DTR7 8 RTS CTS8 7 CTS RTS

1.12 PC to RS485 Interface

Fig-14: PC RS485 INTERFACEFigure 1: Circuit Diagram of Isolated RS485 InterfaceFigure 1 shows the circuit diagram of RS485 interface. Connector K1 is linked to the serial port of the PC, power to the PC side of the circuit is derived from the signal lines DTR and RTS. Positive supply is derived from RTS and negative supply from the DTR line. The RTS line is also used to control the data direction of RS485 driver IC U4. Optical isolation is achieved by optocouplers U1, U2 and U3. Opto U1 is used to control the data direction of U4 opto U2 provide RXD line isolation while

opto U3 provide TXD line isolation. The other side of the isolator carries TTL levels. This side is powered by an unregulated dc supply between 9V and 18V dc. IC U5 provide 5V regulated output and IC U4 provide the RS485 bus interface. The TXD and RXD lines status are provided by data indicating LEDs. The interface has been tested at the baud rate of 19.2k baud. For Data Reception RTS = 1 (at +ve level) For Data Transmition RTS = 0 (at -ve level) DTR line is always set to 0 (at -ve level) Figure 2 & 3 shows the component layout of the isolator pcb and the track patterns respectively.

Fig-15: Component layout of the Isolator PCB

Figure 16: Track patterns of the Isolator PCB

Component details of the project. 1 4 C1,C2,C3,C6 100nF 2 1 C4 10uF 16V 3 1 C5 470uF 25V 4 3 D1,D2,D3 1N4148 5 2 D4,D5 LED RED 3mm 6 2 D7,D6 TRANSIL 6.8V 7 1 D8 1N4003 8 1 K1 DB9 R/A PCB PLUG 9 1 K2 PCB TERMINAL BLOCK 4 WAY 10 3 R1,R2,R3 1K8 11 2 R7,R4 4K7 12 2 R5,R8 1K 13 3 R9,R12 150R 14 1 R6 680R 15 2 R11,R10 10R

16 1 R13 120R 17 2 U3,U1 H11L1 OPTO-ISOLATOR 18 1 U2 CNY17-3 OPTO-ISOLATOR 19 1 U4 MAX487, SN75176B 20 1 U5 LM7805

PLC programming cables for several brandsMost PLC's can be programmed from a PC via a serial cable. Unfortunately, many of these cables have a non standard layout. De cables shown here can be bought from the regular sales channels, but it is often much cheaper to solder them yourself.Mitsubishi PLC cable layoutsMelsec PLC's from Mitsubishi can be connected to PC's running Medoc programming software using various cables. Each different I/O module uses a different pin assignment. Not all Mitsubishi PLCs can be connected directly to a programming PC. The signal levels of the A series CPU units are not RS232 compatible and must be converted with a SC-02N or SC-05 converter. The serial cable layout to connect this converter to a PC is shown in this diagram. PC to Mitsubishi SC-02N/SC-05 adapter cable

If more than one serial port is necessary on an A series melsec PLC, the AJ71C24 or AJ71C21 serial communication modules can be plugged into the system. These modules provide RS232 compatible serial ports, so no signal conversion is necessary to connect these modules with a PC. Both modules are equipped with a DB25 connector. The cable layout for these two modules is shown below. PC to Mitsubishi AJ71C24 serial programming cable

PC to Mitsubishi AJ71C21 serial programming cable

The A1SJ71C24-R2 can also be used to connect computers and devices to a melsec series A PLC. This plug-in module contains two serial ports, each with a DB9 connector. The wiring layout is in fact identical to the

PC to Mitsubishi A1SJ71C24-R2 serial programming cable

Omron PLC cable layoutsThe PLC's from Omron can be connected to various peripheral equipment. Each device requires its own cable layout. Only the more common cables are shown here.

DB9 RS232 programming cable

DB25 RS232 programming cable

CV500-CIF01 tool bus programming cable

Siemens PLC'sMost programming of Siemens S5 PLC's is done using a special RS232 to TTY converter. The S7 series are programmed using a RS232 to MPI bus converter. The easiest thing to do is buy these special cables from your local Siemens supplier. The operator terminals however can be programmed using a normal serial cable. The following cable can be used to program the OP series of operator displays. Programming cable for OPxx display series

Systematic approach to designing a process control systemfirst, we need to select an instrument or a system that you wish to control. Automated system can be a machine or a process and can also be called a process control system. Function of a process control system is constantly watched by input devices (sensors) that give signals to a PLC controller. In response to this, PLC controller sends a signal to external output devices (operative instruments) that actually control how system functions in an assigned manner (for simplification it is recommended that we draw a block diagram of operations’ flow).

Secondly, we need to specify all input and output instruments that will be connected to a PLC controller. Input devices are various switches, sensors and such. Output devices can be solenoids, electromagnetic valves, motors, relays, magnetic starters as well as instruments for sound and light signalization.

Following an identification of all input and output instruments, corresponding designations are assigned to input and output lines of a PLC controller. Allotment of these designations is in fact an allocation of inputs and outputs on a PLC controller which correspond to inputs and outputs of a system being designed.

Thirdly, should make a ladder diagram for a program by following the sequence of operations that was determined in the first step.

Finally, program is entered into the PLC controller memory. When finished with programming, checkup is done for any existing errors in a program code (using functions for diagnostics) and, if possible, an entire operation is

http://www.mikroe.com/en/books/plcbook/chapter1/chapter1.htm#1.3%231.3

simulated. Before this system is started, we need to check once again whether all input and output instruments are connected to correct inputs or outputs.

Maintenance Part

Fig-17:Font view of plc

Fig-18: Power Circuit of PLC

Fig-19: Control circuit of PLC

Problem:Power Failure

Solution:Power section of PLC fault occurred.Replace capacitor

Economical Benefit Using a PLC Control Panel Board

Increased productionImproved qualityGreater product uniformitySaving in raw materialsSaving in energySaving in manpowerIncrease safety

Chapter Two

2.1 IntroductionAn inverter is an electrical device that converts direct current (DC) to alternating current (AC); the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits. An inverter is essentially the opposite of a rectifier.Static inverters have no moving parts and are used in a wide range of applications, from small switching power supplies in computers, to large electric utility high-voltage direct current applications that transport bulk power. Inverters are commonly used to supply AC power from DC sources such as solar panels or batteries.Inverter designed to provide 115 VAC from the 12 VDC source provided in an automobile. The unit shown provides up to 1.2 amperes of alternating current, or just enough to power two sixty watt light bulbs. An inverter converts the DC electricity from sources such as batteries, solar panels, or fuel cells to AC electricity. The electricity can be at any required voltage; in particular it can operate AC equipment designed for mains operation, or rectified to produce DC at any desired voltage.

Grid tie inverters can feed energy back into the distribution network because they produce alternating current with the same wave shape and frequency as supplied by the distribution system. They can also switch off automatically in the event of a blackout.Micro-inverters convert direct current from individual solar panels into alternating current for the electric grid

A variable-frequency drive controls the operating speed of an AC motor by controlling the frequency and voltage of the power supplied to the motor. An inverter provides the controlled power. In most cases, the variable-frequency drive includes a rectifier so that DC power for the inverter can be provided from

main AC power. Since an inverter is the key component, variable-frequency drives are sometimes called inverter drives or just inverters.

2.2 Main part of inverterInput SectionControl SectionPower SectionOutput Section

Input section There are many parts of input section RectifierBreaking resistorHealth relay

Control SectionThere are three types of controlKey pad TerminalCommunication

Power SectionMain parts of power SectionSMPS cardIGBT

Output SectionDC ConverterChopper transformer

Operation mode Frequency reference modeKeypad modeTerminal modeCommunication modeInput functionAnalogDigital

Analog inputVariable pot, Terminal RS232ACC-Accelerations timeDEC-De acceleration time

Base frequencyMaximum frequency

Digital inputFWD-ForwardREV-ReverseRST-ResetMultifunction 1Multifunction 2Multifunction 3 2.3 Inverter SpecificationIG-5AkW/Voltage Ratings:o 0.75 ~ 55kW, 3 phase, 200 ~ 230VACo 0.75 ~ 75kW, 3 phase, 380 ~ 480VAC- Selectable V/f, Sensor less vector, Sensor vector control (Optional)- Built-in process PID control- Optimum acceleration & deceleration for a maximum torque- APP parameter group for special operations; Traverse, Multi Motor Control, DRAW- Multi-function I/O terminal: Input: 27 functions / Output: 21 functions- Multi Motor Control (Up to 4 motors: Optional)- Motor parameter Auto-tuning- Parameter Read/Write function using a detachable LCD Keypad

Fig-20: Inverter iG5A-4

- Power terminal configuration

SymbolsFunctions

R

AC Line input (3 Phase 200-230 VAC or 380-460 VAC)S

T

G Earth Ground

U

3 Phase power output terminal to motor (3 Phase 200-230 VAC or 380-460 VAC)V

W

G Earth Ground

P1 Positive DC bus terminalExternal DC Reactor connection terminal and DB Unit connection terminal

LS Starvert iG5A is very competitive in its price and its functional strength compared to iG5. User-friendly interface, extended inverter ranges up to 7.5kW,

superb torque competence and small size of iG5A provides an optimized user environment.Selectable V/f, sensor less vector control- Motor parameter Auto-tuning- Powerful torque at overall speed range- 0.1 ~ 400Hz frequency output- -15% ~ +10% input voltage margin- Fault history: Last 5 faults- 0~10Vdc / -10 ~ +10Vdc analog input- IP20 enclosure, UL Type 1 (Option)- Selectable manual/automatic torque boost- Selectable PNP/NPN input signal- 2nd motor control and parameter setting- Built-in Dynamic braking transistor as standard- Enhanced process PID control- Built-in RS485 (LS Bus / Modbus RTU) communication- Cooling fan On/Off control & Easy change- Remote control using external keypad * RJ45 cable(Optional)- Upgraded functions: Sleep & Wake-up (Energy savings) KEBKinetic Energy Buffering) protection Low l (eakage PWM algorism- Monitoring & commissioning PC based software toolIP5A

Starvert iP5A series adopt various functions as standard for operation of Fan and Pump. iP5A's optimum performance for Fan & Pump, you can optimize system stability in user-environment and reduce system construction cost.

- Dual PID

When additional PID control or Cascade PID control is required, Dual PID provides users various uses of the system with only iP5A.

- Multi Motor Control

The built-in algebra control function enables an inverter to control many motors without a controller so that user can take advantage of energy-saving and cost-down.

- Sleep and Wake-Up

The built-in energy saving function makes inverter stop automatically when the capacity is very low.

- Pre Heater

The pre heater function is built-in to prevent motor damage and inverter break-down caused from humidity.

- Flying Start

When the inverter drives many ventilators or when the fan in a big load system turns due to a natural convection, iP5A operates the motor by searching the motor speed automatically.

- Auto energy saving

iP5A provides the auto energy saving function by the optimal flux control which minimizes an energy loss caused by a change of the load.

- Improved Management from Instant Power-off and Power Dip Generation

During the power Dip or instant power-off, which is generated by lightening, ground fault and power-failure, loads still keep the mechanical energy and this energy flows back to inverter by regeneration. The power-failure guarantee time is extended by using this electrical character of inverter.

- Constant and Stable Performance (24 hours 365 days)

Regardless of outside alteration such as input voltage variation by load change or weather effect, iP5A can handle moter and load with best performance.

- Safety Stop

When unexpected power-failure blocks power supply, inverter stops motor by using inertia energy of load that prevents unexpected second accident (Parameter setting is required).

Specification

- 200V Class

SV ¡ iP5A - 2 055 075 110 150 185 220 300

Motor Rating1)

[HP] 7.5 10 15 20 25 30 40

[kW] 5.5 7.5 11 15 18.5 22 30

Output ratings

Capacity[kVA]2) 9.1 12.2 17.5 22.9 28.2 33.5 43.8

Rated current[A] 24 32 46 60 74 88 115

Output frequency 0.01 ~ 120 [Hz]

Output voltage(V) 200 ~ 230V

Input ratings

Voltage[V] 3 Phase 200~230 V (-15% ~ +10%)

Frequency 50 ~ 60 [Hz] (± 5%)

Weight (kg) 4.9 6 6 13 13.5 20 20

- 400V Class

SV iP5A - 4 055 075 110 150 185 220 300

Motor Rating1)

[HP] 7.5 10 15 20 25 30 40

[kW] 5.5 7.5 11 15 18.5 22 30

Output ratings

Capacity[kVA]2) 9.6 12.7 19.1 23.9 31.1 35.9 48.6

Rated current[A] 12 16 24 30 39 45 61


Output voltage(V) 380 ~ 480V3)

Input ratings

Voltage[V] 3 Phase 380~480 V (-15% ~ +10%)

Frequency 50 ~ 60 [Hz] (± 5%)

Weight (kg) 4.9 6 6 12.5 13 20 20

SV iP5A - 4 370 450 550 750 900 1100 1320

Motor Rating1)

[HP] 50 60 75 100 125 150 175

[kW] 37 45 55 75 90 110 132

Output ratings

Capacity[kVA]2) 59.8 72.5 87.6 121.1 145.8 178 210

Rated current[A] 75 91 110 152 183 223 264


Output voltage(V) 3 Phase 380~480V3)

Input ratings

Voltage[V] 3 Phase 380~480 V (-15% ~ +10%)

Frequency 50 ~ 60 [Hz] (± 5%)

Weight (kg) 27 27 29 42 43 101 101

SV iP5A - 4 1600 2200 2800 3150 3750 4500

Motor Rating1)

[HP] 215 300 350 400 500 600

[kW] 160 220 280 315 375 450

Output ratings

Capacity[kVA]2) 259 344 436 488 582 699

Rated current[A] 325 432 547 613 731 877


Output voltage(V) 3 Phase 380~480V3)

Input ratings

Voltage[V] 3 Phase 380~480 V (-15% ~ +10%)

Frequency 50 ~ 60 [Hz] (± 5%)

Weight (kg) 114 200 200 243 280 380

1) Indicates the maximum applicable capacity when using a 4-Pole LG motor.2) Rated capacity (v 3×V×I) is based on 220V for 200V class and 460V for 400V class.3) Maximum output voltage will not exceed the input voltage. An output voltage less than the input voltage may be programmed if necessary.

Commonspecifications

Dynamic braking torque

Max. braking torque

20% continuous4)

ED Option (braking UNIT, braking resistor) 4)

Cooling method Forced air cooling

Protection degree

IP20, UL Enclosed Type 1(provided with conduit box) for all ratings, UL Open type from 15 to 90 kW (Optional conduit plate)

Control Control method V/F, Sensor less Vector, Slip Compensation, Easy Start Selectable

Frequency setting resolution

Digital reference: 0.01Hz(Below 100Hz), 0.1Hz(Over 100Hz), Analog reference: 0.01Hz/60Hz

Frequency accuracy Digital: 0.01% of max. output freqAnalog: 0.1% of max. output freq

V/F ratio Linear, Square pattern, User V/F

Overload capacity 110% per 1min, 120% per 1min5)

Torque boost Manual torque boost(0 to 15% adjustable), auto torque boost

Operation

Operation method Keypad/Terminal/Communication selectable

Frequency setting resolution

Analog:0~12V/-12V~12V/4~20mA/0~20mA/Pulse/Ext-PID, Digital: Keypad

Input signal

Start signal Forward, Reverse

Multi-StepUp to 18 Speeds can be set including Jog (Use Programmable Digital Input Terminal)

Multi-Step Accel/Decel time

0.1~ 6,000 sec, Max 4 types can be set via Multi- Function Terminal.Accel/Decel Pattern: Linear, U-Curve, S-Curve Selectable

Emergency stop Interrupts the Output of Inverter

Jog Jog operation

Fault reset Reset the fault when the protective function is active.

Output signal

Operating status

Frequency Detection Level, Overload Alarm, Stalling, Over Voltage, Low Voltage, Inverter Overheating/ Running/ Stopping/ Constant running, Inverter By-Pass, Speed Searching

Fault output Contact Output (3A, 3C, 3B) - AC 250V 1A, DC 30V 1A

Indicator

Choose 2 from Output Frequency, Output Current, Output Voltage, DC LinkVoltage (Output Voltage: 0 ~ 10V)

Operation function

DC Braking, Frequency Limit, Frequency Jump, 2nd Function, Slip Compensation, Reverse Rotation Prevention, Auto Restart, Inverter By-Pass, Auto-Tuning, PID Control, Flying Start, Safety Stop, Flux Braking, Low leakage, Pre-PID, Dual-PID, MMC, Easy Start, Pre-heater

Protection function

Inverter trip

Over Voltage, Low Voltage, Over Current, Ground Fault , Inverter Overheat, Motor Overheat, Output Phase Open, Overload Protection, External Fault 1, 2, Communication Error, Loss of Speed Command, Hardware Fault, Option Fault, etc

Inverter alarm Stall Prevention, Overload Alarm, Thermal Sensor Fault

Momentary power loss

Below 1 sec: Continuous operation, Above 1 sec: Auto restart active when Safety Stop is set to "Yes" with a fan connected.

Keypad

Operation information

Output Frequency, Output Current, Output Voltage, Frequency Set Value, Operating Speed, DC Voltage, Integrating Wattmeter, Fan ON time, Run-time, Last Trip Time.

Trip information

Trips Indication when the Protection Function activates. Max. 5 Faults are saved. Last Trip Time.

Environment

Ambient temperature -10¡É~40¡É (use loads less than 80% at 50¡É)

Storage temperature -20¡É~65¡É

Ambient humidity Less than 90% RH Max. (No condensing)

Altitude, Vibration Below 1,000m· Below 5.9m/sec² (=0.6g)

Application site Pollution degree 2, No Corrosive Gas, Combustible Gas, Oil Mist, or Dust

IV5

Fig: 21-Inverter IV5

S Starvert iV5 series realizes the high precision vector control in entire operational area and its highly precise speed control guarantees superb control stability in the elevator controls.Auto tuningIn the application which requires a high torque at low speed, the electrical parameters of motor should be properly set for an optimal operation. Auto tuning function of iV5 make users to set the motor variable accurately.- various communication interface

iV5 provides various communication interface such as RS 485, Device NET, Profibus-DP and Modbus-RTU.- Extended function card (ENC_DIV,DIAO and ELIO)Option card for the encoder pulse division (ENC_DIV) supports the encoder with open collector output and can divide the encoder pulse up to 1/128. Digital input and Analog signal output card (DIAO) can receive the binary speed command from PLC or other upper level controller and has 4 channels of analog signal output. ELIO card enables the lift application software to be available for an optimized lift operation.

Terminal configuration

Power terminal configuration

Symbol Name Description

R,S,T AC Input3Phase AC input connection1) 200V: 200~230V, 50/60Hz2) 400V: 300~460V, 50/60Hz

U,V,W Output Cable connection of 3 phase induction motor

G Earth ground Inverter frame earth terminal

B1,B2 Braking resistor Braking resistor connection

P1,P2 DC reactor and Braking unit

DC reactor, braking unit and DC link common connection terminal

P DC Link(+-) terminal DC Link common connection terminal

N DC Link(-) terminal Braking unit and DC link common terminal

Control terminal configuration

Item DisplayName Description

Digital input FX Forward run

command 'ON' when tied to CM terminal

RX Reverse run command

Stops when FX, RX are ON / OFF simultaneously

BX Emergency stop

ON when closed to CM, FREERUN Stop and Deceleration stop. It does not trigger fault alarm signal.

RST Fault reset Clears the fault condition when the fault state is removed.

P1

Multi-function input terminal

Selectable among the following 27 functions:(Multi step speed selection 1/2/3, JOG run, MOP up/down/Save/Clear, Analog hold, Main drive, Second function, Speed Acc/Dec time selection, 3-wire operation, External default signal B contact point, Forward rotation prevention, Process PI disable, Timer input, Soft start cancellation, ASR PI Gain selection, ASR P.PI selection, Flux reference selection, Pre-excitation, Speed/Torque control selection, Torque limit use, Torque bias

P2

P3

P4

P5

P6

P7

CM COMMON "ON" in case of connection between CM and digital

Analog input VREF

Power supply for Analog setting

Reference voltage by variable resistor ( + 10V ) : 10k§Ù

AI1 Voltage/ Current Signal Input

- Voltage signal input (-10 ~ 10V), current signal input (4 ~ 20mA), Motor NTC selectable via Multi-function Analog input.- Selectable among following 8 different functions;Speed/Torque/Flux command, Torque bias, Torque limit,Process PI controller command, Process PI controller feedback value, Draw command, Motor NTC input)

AI2

AI3 Voltage/ Motor NTC input

- Jumper setting in Voltage Input: Closed (Jumper connected as Default)- AI1, AI2: Open (Jumper disconnected), AI3: Switch set on left side - Jumper setting in Current Input

5G COMMON - COMMON terminal for analog input

P5 Power supply for open collector

- +5V

5G - 0V

Encored input

A+ Encoder A-phase signal

- A, B signal for Line Drive Type Encoder.- Short P5 pin of JP2 on I/O PCB and set JP1 switch to LD for the use of Line Drive.

A-

B+ Encoder B-phase signal

B-

P15 Power supply for open collector

+ 15 V

5G 0 V

PA

Encoder signal output : A-Phase

- A, B signal for Complementary or Open Collector Type Encoder.- Short P15 pin of JP2 on I/O PCB and set JP1 switch to "OC".

PB Encoder

signal output: B-Phase

Analog output

AO1 Analog output 1

Output range: -10V ~ +10VSelectable among 31 (Motor speed, speed ref. 1~2, Torque command 1~2, torque current, flux ref., flux current, Inverter output current/voltage, Motor Temp, DC link voltage¡¦ )

AO2 Analog output 2

AO3 Analog output 3

5G COMMON COMMON terminal for analog output

Open collector output

OC1

Open collector output

Selectable among the following 14 functions;Zero speed detect, Speed detect (Bi-directional), Speed detect (Uni-directional), Speed reach, Speed deviation, Torque detect, On Torque limit, Motor overheat, Inverter overheat, on low voltage, Inverter running, Inverter regenerating, Inverter ready,Timer output

OC2

OC3

EG

Digital output

1A Multi-function input 1 (A Contact)1B

2A Multi-function input 2 (A Contact)2B

30A Fault alarm Outputs when fault occurs.

A contact

Deactivated in BX condition.30B Fault alarm

B contact

30C COMMON COMMON for 30A, 30B

KEY PAD

Keypad features

2.4 Connection Diagram of inverter

2.5 Types of FaultOver currentOver current 2Ground FaultInverter OverloadOverload TripInverter Overheat

Output Phase lossOver VoltageLow VoltageElectronic ThermalInput Phase lossSelf diagnostic multifunctionParameter save errorInve3rter hardware FaultCommunication ErrorKey pad ErrorCooling fan ErrorInstant cut offExternal Fault A contact inputBrake contra ErrorOver current FaultOver Current 2Ground fault current

Model:SV008iG5-A-4Fault: Inverter has no powerSolution:SMPS Circuit ProblemReplace SMPS Circuit

Model:SV005iS5-4Fault: No PowerSolution:Cooling Fan FaultCircuit ServicingReplace Cooling FanModel:SV022iS5A-4Fault: No PowerSolution:Power Card FaultIGBT FaultSMPS Card FaultDamage Braking Resistor

Replace IGBTReplace SMPS CardReplace Braking Resistor(200 Ohm)

Model:SV022iS5A-4Fault: Key pad LED Direct flashingSolution:Polar Capacitor Fault Replace it, new polar capacitor solder there.

Model:SV008iG5-A-4Fault: Output Error

Solution:Replace IR2133J Rectifier.Model:HV008iG-1Fault: Key pad light (Run,Set,Rev,Fw) flashing at a time.Solution:IGBT FaultReplace IGBTModel:SV044iG5-2Fault: Low voltage faultSolution:Replace Power circuit resistor

Model:IG5440-4Fault: Does not show display. Solution:SMPS Card faultReplace capacitor of SMPS card

Model:SV022iS5A-4

Fault: No PowerSolution:Power Card FaultIGBT FaultSMPS Card FaultDamage Braking ResistorReplace IGBTReplace SMPS CardReplace Braking Resistor (200 Ohm)

Fig-22: Inverter synchronization

Fig-23: Sub Power PCB of inverter

Fig-24: Main Power PCB

Fig-24: Main Power PCB

Fig-25: Control card of Inverter

Fig-:26 Burnt IGBT

Fig-:27 IGBT Test

Fig-:28: Rectifier

Conclusion:PLC (Programmable Logic Controller) and Inverter is a latest intelligent instrument that is used widely in different industrial plants to operate automatically with decreasing the plants breakdown times as well as its maintenance costs and increasing both of quality and quantity of productions. Considering of its high reliability and low cost most of the organizations are now trying to replace their old control system with new PLC control system. So as an Electrical Engineer sufficient knowledge about PLC and Inverter should know.

Accuracy: The closeness of an indication or reading of a measurement device to the actual value of the quantity being measured. Usually expressed as ± percent of full scale output or reading. Active Power: The product of the voltage across a branch of an alternating-current circuit and the component of the electric current that is in phase with the voltage.Adapter: A mechanism or device for attaching non-mating parts. .

Air Compressors: An air compressor or a gas compressor operates on the simple principle of taking in a quantity of air or a certain gas and increasing its pressure many times over by reducing its volume.Ammeter: An instrument used to measure current. Ampere (amp): A unit used to define the rate of flow of electricity (current) in a circuit; units are one coulomb (6.28 x 1018 electronics) per second. Amplifier: A device which draws power from a source other than the input signal and which produces as an output an enlarged reproduction of the essential features of its input. Amplitude Span: The Y-axis range of a graphic display of data in either the time or frequency domain. Usually a log display (dB) but can also be linear. Amplitude: A measurement of the distance from the highest to the lowest excursion of motion, as in the case of mechanical body in oscillation or the peak-to-peak swing of an electrical waveform. Application Program: A computer program that accomplishes specific tasks, such as word processing. Apparent Power: The product of the root-mean-square voltage and the root-mean-square current delivered in an alternating-current circuit, no account being taken of the phase difference between voltage and current.ASCII: American Standard Code for Information Interchange. A seven or eight bit code used to represent alphanumeric characters. It is the standard code used for communications between data processing systems and associated equipment. ASME: American Society of Mechanical Engineers. ASTM: American Society for Testing and Materials. Auto-Zero: An automatic internal correction for offsets and/or drift at zero voltage input. Automatic Reset: 1. A feature on a limit controller that automatically resets the controller when the controlled temperature returns to within the limit bandwidth set. 2. The integral function on a PID controller which adjusts the proportional bandwidth with respect to the set point to compensate for droop in the circuit, i.e., adjusts the controlled temperature to a set point after the system stabilizes. AWG: American Wire Gage. Best Fit Straight Line (BFSL): A line midway between two parallel straight lines enclosing all output vs. pressure values. Beta Ratio: The ratio of the diameter of a pipeline constriction to the unconstricted pipe diameter. BIAS Current: A very low-level DC current generated by the panel meter and superimposed on the signal. This current may introduce a measurable offset across a very high source impedance. Breakdown Voltage Rating: The dc or ac voltage which can be applied across insulation portions of a transducer without arcing or conduction above a specific value. Bridge Resistance: See Input impedance and Output impedance. BTU: British thermal units. The quantity of thermal energy required to raise one pound of water at its maximum density, 1 degree F. One BTU is equivalent to .293 watt hours, or 252 calories. One kilowatt hour is equivalent to 3412 BTU. Buffer Capacity (B): A measure of the ability of the solution to resist pH change when a strong acid or base is added. Bulb (Liquid-in-Glass Thermometer): The area at the tip of a liquid-in-glass thermometer containing the liquid reservoir. Burn-In: A long term screening test that is effective in weeding out infant mortalities because it simulates actual or worst case operation of the device, accelerated through a time, power, and temperature relationship.

Capacitor: An electric circuit element used to store charge temporarily, consisting in general of two metallic plates separated and insulated from each other by a dielectric. Ceramic Insulation: High-temperature compositions of metal oxides used to insulate a pair of thermocouple wires The most common are Alumina (Al2O3), Beryllia (BeO), and Magnesia (MgO). Their application depends upon temperature and type of thermocouple. High-purity alumina is required for platinum alloy thermocouples. Ceramic insulators are available as single and multihole tubes or as beads. Ceramic: Polycrystalline ferroelectric materials which are used as the sensing units in piezoelectric accelerometers. CFM: The volumetric flow rate of a liquid or gas in cubic feet per minute. Charge Sensitivity: For accelerometers that are rated in terms of charge sensitivity, the output voltage (V) is proportional to the charge (Q) divided by the shunt capacitance (C). This type of accelerometer is characterized by a high output impedance. Chatter: The rapid cycling on and off of a relay in a control process due to insufficient bandwidth in the controller. CHROMEGA®: A chromium-nickel alloy which makes up the positive leg of type K and type E thermocouples (registered trademarks of OMEGA ENGINEERING, INC.). Circuit Breaker: An automatic switch that stops the flow of electric current in a suddenly overloaded or otherwise abnormally stressed electric circuit.Clear: To restore a device to a prescribed initial state, usually the zero state. Clipping: The term applied to the phenomenon which occurs when an output signal is limited in some way by the full range of an amplifier, ADC or other device. Clock: The device that generates periodic signals for synchronization. Closeness of Control: Total temperature variation from a desired set point of system. CMV (Common-Mode Voltage): The AC or DC voltage which is tolerable between signal and ground. One type of CMV is specified between SIG LO and PWR GND. In differential meters, a second type of CMV is specified between SIG HI or LO and ANA GND (METER GND). Compensation: An addition of specific materials or devices to counteract a known error. Conductance: The measure of the ability of a solution to carry an electrical current. (See Equivalent Conductance) Conduction: Conveying of electrical energy or heat through or by means of a conductor. Confidence Level: The range within which the true value of a measured quantity exists. Control Mode: The output form or type of control action used by a temperature controller to control temperature, i.e., on/off, time proportioning, PID. Control Point: The temperature at which a system is to be maintained. Convection: 1. The circulatory motion that occurs in a fluid at a non-uniform temperature owing to the variation of its density and the action of gravity. 2. The transfer of heat by this automatic circulation of fluid. Coulomb Sensitivity: Charge/unit acceleration, expressed in Pc/g (charge sensitivity). Counter Weight: A weight added to a body so as to reduce a calculated unbalance at a desired place. CPU: Central processing unit. The part of the computer that contains the circuits that control and perform the execution of computer instructions. Critical Damping: Critical damping is the smallest amount of damping at which a given system is able to respond to a step function without overshoot. Critical Speed: The rotational speed of the rotor or rotating element at which resonance occurs in the system. The shaft speed at which at least one of the "critical" or natural frequencies of a shaft is excited.

Current: The rate of flow of electricity. The unit of the ampere (A) defined as 1 ampere = 1 coulomb per second. Current Transformer: In electrical engineering, a current transformer (CT) is used for measurement of electric currents. Current transformers are also known as instrument transformers.DC: Direct current; an electric current flowing in one direction only and substantially constant in value. Dead Band: 1. For chart records: the minimum change of input signal required to cause a deflection in the pen position. 2. For temperature controllers: the temperature band where heat is turned off upon rising temperature and turned on upon falling temperature expressed in degrees. The area where no heating (or cooling) takes place. Density: Mass per unit of volume of a substance. I.E.: grams/cu.cm. or pounds/cu.ft. Derivative: Derivative function senses the rate of rise or fall of the system temperature Deviation: The difference between the value of the controlled variable and the value at which it is being controlled. Dissipation Constant: The ratio for a thermistor which relates a change in internal power dissipation to a resultant change of body temperature. Dissociation Constant (K): A value which quantitatively expresses the extent to which a substance dissociates in solution. The smaller the value of K, the less dissociation of the species in solution. This value varies with temperature, ionic strength, and the nature of the solvent. Duplex Wire: A pair of wires insulated from each other and with an outer jacket of insulation around the inner insulated pair. Duty Cycle: The total time to one on/off cycle. Usually refers to the on/off cycle time of a temperature controller. Dynamic (Two-Plane) Balancing Machine: A dynamic balancing machine is a centrifugal balancing machine that furnishes information for performing two-plane balancing. Electrical Interference: Electrical noise induced upon the signal wires that obscures the wanted information signal. Electrode Potential (E): The difference in potential established between an electrode and a solution when the electrode is immersed in the solution. Electromotive Force (emf): The potential difference between the two electrodes in a cell. The cell emf is the cell voltage measured when no current is flowing through the cell. It can be measured by means of a pH meter with high input impedance. Electronic Industries Association (EIA): A standards organization specializing in the electrical and functional characteristics of interface equipment. EMF: Electromotive force. A rise in (electrical) potential energy. End Points: The end points of a full scale calibration curve. Ferrule: A compressible tubular fitting that is compressed onto a probe inside a compression fitting to form a gas-tight seal. Ferannti Effect: A rise in voltage occurring at the end of a long transmission line when its load is disconnected. Frequency: N number of cycles over a specified time period over which an event occurs. Gain: The amount of amplification used in an electrical circuit. Galvanometer: An instrument that measures small electrical currents by means of deflecting magnetic coils.Generator: A device that produces electric current, usually by rotating a conductor in a magnetic field, thereby generating current through electromagnetic induction. Hertz (Hz): Units in which frequency is expressed. Synonymous with cycles per second. values. Machine language programs are often written in hexadecimal notation.

Horse Power: A unit of power in the U.S. Customary System, equal to 745.7 watts or 33,000 foot-pounds per minute.Impedance: The total opposition to electrical flow (resistive plus reactive). Input Impedance: The resistance measured across the excitation terminals of a transducer. Insulation Resistance: The resistance measured between two insulated points on a transducer when a specific dc voltage is applied at room temperature. IPTS-48: International Practical Temperature Scale of 1948. Fixed points in thermometry specified by Ninth General Conference held in 1948. ISA: Instrument Society of America. Isolation: The reduction of the capacity of a system to respond to an external force by use of resilient isolating materials. Isolator: A passive attenuator in which the loss in one direction is much greater than that in the opposite direction; a ferrite isolator for waveguides is an example.Joule: The basic unit of thermal energy. Junction: The point in a thermocouple where the two dissimilar metals are joined. Kilowatt (kw): Equivalent to 1000 watts. Kilowatt Hour (kwh): 1000 watthours. Kilovolt amperes (kva): 1000 volt amps. Kinetic Energy: Energy associated with mass in motion, i.e., 1/2 rV2 where r is the density of the moving mass and V is its velocity. KVA: Kilovolt amperes (1000-volt amps). Lag: 1. A time delay between the output of a signal and the response of the instrument to which the signal is sent. 2. A time relationship between two waveforms where a fixed reference point on one wave occurs after the same point of the reference wave. Leakage Rate: The maximum rate at which a fluid is permitted or determined to leak through a seal. The type of fluid, the differential Limits of Error: A tolerance band for the thermal electric response of thermocouple wire expressed in degrees or percentage defined by ANSI specification MC-96.1 (1975). Lightning surge: A transient disturbance in an electric circuit due to lightning.Limits of Error: A tolerance band for the thermal electric response of thermocouple wire expressed in degrees or percentage defined by ANSI specification MC-96.1 (1975). Linearity: The closeness of a calibration curve to a specified straight line. Linearity is expressed as the maximum deviation of any calibration point on a specified straight line during any one calibration cycle. of this potential depends on the composition of the liquids and the type of junction used. Load Impedance: The impedance presented to the output terminals of a transducer by the associated external circuitry. Load: The electrical demand of a process expressed as power (watts), current (amps) or resistance (ohms). Load Line: A straight line drawn across a series of tube or transistor characteristic curves to show how output signal current will change with input signal voltage when a specified load resistance is used.Load Break Switch: An electric switch in a circuit with several hundred thousand volts, designed to carry a large amount of current without overheating the open position, having enough insulation to isolate the circuit in closed position, and equipped with arc interrupters to interrupt the load current.Maximum Power Rating: The maximum power in watts that a device can safely handle. Microamp: One millionth of an ampere, 10-6 amps, µA. Microvolt: One millionth of a volt, 10-6 volts. Mil: One thousandth of an inch (.001"). Milliamp: One thousandth of an amp, 10-3 amps, symbol mA.

Millimeter: One thousandth of a meter, symbol mm. Millivolt: Unit of electromotive forceN/C (No Connection): A connector point for which there is no internal connection. NBS: National Bureau of Standards. NEC: National Electric Codes. Negative Temperature Coefficient: A decrease in resistance with an increase in temperature. NEMA-4: A standard from the National Electrical Manufacturers Association, which defines enclosures intended for indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, and hose-directed water. NEMA-7: A standard from the National Electrical Manufacturers Association, which defines explosion-proof enclosures for use in locations classified as Class I, Groups A, B, C or D, as specified in the National Electrical Code. NEMA-12: A standard from the National Electrical Manufacturers Association, which defines enclosures with protection against dirt, dust, splashes by non-corrosive liquids, and salt spray. input terminals. NPT: National Pipe Thread. Null: A condition, such as balance, which results in a minimum absolute value of output. O.D.: Outside diameter. Octal: Pertaining to a base 8 number system. Oscillating Circuit: An electric circuit with values of capacitance and inductance that cause its current, charge, and electric potential to oscillate in a sinusoidal pattern.Ohmeter: An instrument used to measure electrical resistance. On/off Controller: A controller whose action is fully on or fully off. Open Circuit: The lack of electrical contact in any part of the measuring circuit. Peripheral: A device that is external to the CPU and main memory, i.e., printer, modem or terminal, but is connected by the appropriate electrical connections. Phase Difference: The time expressed in degrees between the same reference point on two periodic waveforms. Phase Proportioning: A form of temperature control where the power supplied to the process is controlled by limiting the phase angle of the line voltage. Phase: A time based relationship between a periodic function and a reference. In electricity, it is expressed in angular degrees to describe the voltage or current relationship of two alternating waveforms. . Plane Separation: Of a balancing machine, is the operation of reducing the correction plane interference ratio for a particular rotor. Polarity: In electricity, the quality of having two oppositely charged poles, one positive one negative. Port: A signal input (access) or output point on a computer. Potential transformer: An instrument transformer whose primary winding is connected in parallel with a circuit in which the voltage is to be measured or controlled. Also known as potential transformer.Potentiometer: 1. A variable resistor often used to control a circuit. 2. A balancing bridge used to measure voltage. Power Supply: A separate unit or part of a circuit that supplies power to the rest of the circuit or to a system. Principal Axes: The axes of maximum and minimum normal stress. Probe: A generic term that is used to describe many types of temperature sensors.PSIA: Pounds per square inch absolute. Pressure referenced to a vacuum.

PSID: Pounds per square inch differential. Pressure difference between two points. PSIG: Pound per square inch gage. Pressure referenced to ambient air pressure. PSIS: Pounds per square inch standard. Pressure referenced to a standard atmosphere. Range ability: The ratio of the maximum flow rate to the minimum flow rate of a meter. Real Time: The time interval over which the system temperature is sampled for the derivative function. Record: A collection of unrelated information that is treated as a single unit. Recovery Time: The length of time which it takes a transducer to return to normal after applying a proof pressure. Redox Potential: The potential developed by a metallic electrode when placed in a solution containing a species in two different oxidation states. Reference Plane: Any plane perpendicular to the shaft axis to which an amount of unbalance is referred.Register: A storage device with a specific capacity, such as a bit, byte or word. Relay (Mechanical): An electromechanical device that completes or interrupts a circuit by physically moving electrical contacts into contact with each other. Relay (Solid State): A solid state switching device which completes or interrupts a circuit electrically with no moving parts. Residual (Final) Unbalance: Residual unbalance is that unbalance of any kind that remains after balancing. Resistance Ratio Characteristic: For thermistors, the ratio of the resistance of the thermistor at 25°C to the resistance at 125°C. Resistance Temperature Characteristic: A relationship between a thermistor's resistance and the temperature. Resistance: The resistance to the flow of electric current measured in ohms (1/2) for a conductor. Resistance is function of diameter, resistivity (an intrinsic property of the material) and length. Resistor: A device used to control current in an electric circuit by providing resistance.Inductor: One that inducts, especially a device that functions by or introduces inductance into a circuit.Response Time: The length of time required for the output of a transducer to rise to a specified percentage of its final value as a result of a step change of input. Reynolds Number: The ratio of inertial and viscous forces in a fluid defined by the formula Re = rVD/µ, where: r = Density of fluid, µ = Viscosity in centipoise (CP), V = Velocity, and D = Inside diameter of pipe. RFI: Radio frequency interference. Rheostat: A variable resistor. Rise Time: The time required for a sensor or system to respond to an instantaneous step function, measured from the 10% to 90% points on the response waveforms. Root Mean Square (RMS): Square root of the mean of the square of the signal taken during one full cycle. Rotor: A rotor is a rotating body whose journals are supported by bearings. RTD: Resistance temperature detector. SAMA: Scientific Apparatus Makers Association. An association that has issued standards covering platinum, nickel, and copper resistance elements (RTDs). SCE: Saturated calomel electrode. SCR: Ssilicone controlled rectifier. Scroll: To move all or part of the screen material up to down, left or rightSelf Heating: Internal heating of a transducer as a result of power dissipation. Sensing Element: That part of the transducer which reacts directly in response to input.

Sensitivity Shift: A change in slope of the calibration curve for change in sensitivity. Sensitivity: The minimum change in input signal to which an instrument can respond. SI: System InternationalStagnation Pressure: The sum of the static and dynamic pressure. Surge Current: A current of short duration that occurs when power is first applied to capacitive loads or temperature dependent resistive loads such as tungsten or molybdenum heaters-usually lasting no more than several cycles. . Syntax: The rules governing the structure of a language. TEMPCO: Abbreviation for "temperature coefficient": the error introduced by a change in temperature. Normally expressed in %/°C or ppm/°C. Terminal: An input/output device used to enter data into a computer and record the output. Thermal Coefficient of Resistance: The change in resistance of a semiconductor per unit change in temperature over a specific range of temperature. Thermal Conductivity: The property of a material to conduct heat in the form of thermal energy. Thermal Expansion: An increase in size due to an increase in temperature expressed in units of an increase in length or increase in size per degree, i.e. inches/inch/degree C. Thermal Gradient: The distribution of a differential temperature through a body or across a surface. Transformer: A device used to transfer electrical energy from one circuit to another. With an alternating current, a transformer will either raise or lower the voltage Triac: A solid state switching device used to switch alternating current wave forms. . True RMS: The true root-mean-square value of an AC or AC-plus-DC signal, often used to determine power of a signal. Undershoot: The difference in temperature between the temperature a process goes to, below the set point, after the cooling cycle is turned off and the set point temperature. Ungrounded Junction: A form of construction of a thermocouple probe where the hot or measuring junction is fully enclosed by and insulated from the sheath material. Union: A form of pipe fitting where two extension pipes are joined at a separable coupling. Vacuum: Any pressure less than atmospheric pressure.Vacuum pressure: The pressure exerted by a vapor in equilibrium with solid or liquid phase.. Viscosity: The inherent resistance of a substance to flow. Volt: The (electrical) potential difference between two points in a circuit. The fundamental unit is derived as work per unit charge-(V = W/Q). One volt is the potential difference required to move one coulomb of charge between two points in a circuit while using one joule of energy. Voltage: An electrical potential which can be measured in volts. Voltmeter: An instrument used to measure voltage. Volume Flow Rate: Calculated using the area of the full closed conduit and the average fluid velocity in the form, Q = V x A, to arrive at the total volume quantity of flow. Q = volumetric flowrate, V = average fluid velocity, and A = cross sectional area of the pipe. Watt Density: The watts emanating from each square inch of heated surface area of a heater. Expressed in units of watts per square inch. Young's Modulus: Young's Modulus (the Modulus of Elasticity) is equivalent to the ratio of normal stress to strain. Zero Point: The electrical zero point where zero millivolts would be displayed. Used in conjunction with the slope control to provide a narrower range calibration. Zero Power Resistance: The resistance of a thermistor or RTD element with no power being dissipated.

Zero Voltage Switching: The making or breaking of circuit timed such that the transition occurs when the voltage wave form crosses zero voltage; typically only found in solid state switching devices.

AAC Alternating Current (vs DC)ACIA Asynchronous Communication Interface AdapterACL Advanced CMOS Logic (as in 74ACL245)ANSI American National Standards InstituteARRL American Radio Relay LeagueAS Advanced Schottky (as in 74AS245)ASIC Application-Specific Integrated CircuitAVC Automatic Volume Control

B BASIC Beginners' All-purpose Symbolic Instruction CodeBEV Billion Electron VoltsBIFET Bipolar Field-Effect TransistorBNC Baby N ConnectorBW Bandwidth

C CC Constant CurrentCCD Charge Coupled Device (used in cameras)CCITT International Telegraphy and Telephony Consultative CommitteeCCTV Closed Circuit TelevisionCCW Counter Clock-WiseCFM Cubic Feet per MinuteCV Constant VoltageCVT Constant Voltage Transformer (aka ferroresonant by Sola(tm))CW Clock Wise

D D/A Digital to AnalogDAC Digital to Analog Converter | Data Acquisition and ControlDARPA Defense Advanced Research Projects AgencyDAV Data AValiable | DatA Valid (logic signal)DC Direct Current (vs AC)DCD Data Carrier Detect (protocol signal)DPDT Dual Pole Dual Throw (as in a switch)DPI Dots Per Inch (as in resolution)DPST Dual Pole Single Throw (as in a switch) DRAM Dynamic Random Access Memory

E EGA Enhanced Graphics AdapterESA European Space AgencyESD Electrostatic Sensitive Device (aka CMOS :-)

ESR Equivalent Series ResistanceEV Electron Volt

F FET Field Effect TransistorFF Flip FlopFFT Fast Fourier TransformFIFO First In First OutFILO First In Last OutFM Frequency ModulationFORTRAN FORmula TRANslationFP Floating PointFPLA Field Programmable Logic Array

G GA Gate ArrayGAL Generic Array LogicGCS Gate Controller SwitchGFCI Ground Fault Circuit InterrupterGFI Ground Fault Interrupter GFLOPS Billions of Floating Point operations per SecondGIGO Garbage In Garbage Out

H HRC High Rupturing Capacitor HD High DensityHTS High Tension SwitchgearHDC Hard Disk ControllerHVDC High Voltage Direct CurrentHVPS High Voltage Power SupplyHz Hertz (cycles per second)

I IP Interface ProcessorIR Current/Resistance | InfraredIRED Infrared Emitting DiodeISA Instrument Society of AmericaISN Information Systems NetworkISO In Search Of

J JEDEC Joint Electron Device Engineering CouncilJFET Junction Field Effect TransistorJIS Japanese Industrial StandardJPL Jet Propulsion LaboratoryJUG Joint Users Group

K K Kilo (1000 units)KA KiloAmpere (1000A)KBPS KiloBits Per SecondKEV Kilo Electron VoltsKHz Kilo Hertz (1000 cycles per second)KVA Kilo Volt AmperesKWH Kilo Watt Hours

L L InductanceLASER Light Amplification by Stimulated Emission of RadiationLC Inductance and CapacitanceLCD Liquid Crystal DisplayLED Light Emitting DiodeLF Low FrequencyLIFO Last In First OutLW Long Wave

M MDAC Multiplying Digital to Analog ConverterMECL Motorola Emitter Coupled LogicMFLOPS Milions of FLOating Point operations per SecondMFM Modified Frequency ModulationMHz MegaHertz

N NEDA National Electronics Distributors AssociationNEMA National Electrical Manufacturers AssociationNTSC National Television Systems Committee (Never The Same Color twice :-)

O OEM Original Equipment ManufacturerOS Operating SystemOSCAR Orbiting Satellite Carrying Amateur RadioOSHA Occupational Safety and Health AdministrationOTDR Optical Time Domain ReflectrometryOTP One Time Programmable (as in PROM or plastic EPROM)OVP Over Voltage Protection

P PCM Pulse Code ModulationPEC PhotoElectric CellPF Power FactorPG Power GainPIV Peak Inverse VoltagePLA Programmable Logic Array

Q QA Quality AssuranceQC Quality ControlQIC Quarter Inch CartridgeQIP Quad Inline PackageQSM Quad Surface Mount

R R&D Research and DevelopmentRAD Radiation Absorbed DoseRADAR RAdio Detection And Ranging

S SCL Serial CLockSCR Silicon Controller RectifierSCS Silicon Controller SwitchSSR Solid State RelaySSTV Slow Scan TeleVisionSW Short Wave

TT/H Track and HoldTC Temperature CoefficientTCP/IP Transmission Control Protocol/Internet ProtocolTD Tunnel DiodeTDD Telecommunication Devices for the DeafTEM Transverse Electromagnetic (wave)TF Transfer FunctionTFD Thin Film DetectorTFEL Thin Film Electro LuminescentTS Time SharingTTL Transistor Transistor LogicTV TelevisionTWT Traveling Wave Tube

U uF micro Farad (measure of capacitance)UHF Ultra High FrequencyUPS Uninterruptible Power SupplyUSART Universal Synchronous/Asynchronous Receiver/TransmitterUTC Universal Time CodeUV Ultraviolet

VVA Volt AmpereVAC Volts Alternating CurrentVOM Volt Ohmmeter

WWV Working VoltageWW Wire Wound | Wire Wrap

XXMT TransmitXTAL crystal

YYAG Yttrium Aluminum Garnet (laser)YIG Yttrium Iron Garnet

ZZD Zero DefectsZIF Zero Insertion ForceZIP Zigzag Inline Package | Compression scheme

Bibliography

Metha, and Rohit Mehta. Principle of Power System. New Delhi: S. Chand & Company Ltd, 2002.

Nagpal. G.R. Power Plant Engineering. Delhi: Hanna publishers, 2005

Van Valkenburgh, Nooger, and Neville, Basic Electricity, Vol. 5, Hayden Book Company.

Buban and Schmitt, Understanding Electricity and Electronics, 3rd Edition, McGraw-Hill.

Kidwell, Walter, Electrical Instruments and Measurements, McGraw-Hill.

Mason, C. Russel, The Art and Science of Protective Relaying, John Wiley and Sons.

Wikipedia, 2009. D:\voltage stab\Voltage stabilizer [Online] (Updated on 2009) Available at: http://en.wikipedia.org/wiki/V/D_

Alstom, T & D. “ Tutorial of system Protection Grading Study”. Analysis and Protection Of Power Systems Coerce, London: 2002

Rao, Sunil S. Switchgear protection and Power system. 12th ed. Delhi: Khanna Publishers, 2003

Specialist Engineers of GEC Measurement. Protective Relays Application Guide. 2nd ed. London: General Electric, 2001

Stevenson, Jr. Willium D. Elements of Power System Analysis. 4th ed. Tokyo: McGraw -Hill, 2001

Inverter & PLC service and maintenance support by System Engineering Ltd

Documents

inverter drives

electrical inverter

variablefrequency drives

main ac power

inverter plc service

bulk power

controlled power

dc power source utilization