Basic Electrical and Instrumentation Engineering

353 Pages·2021·22.333 MB·English

by  C. Sharmeela, P. Sivaraman, R. Mahendran, A. Thaiyal Nayagi

Basic Electrical and
Instrumentation Engineering
Scrivener Publishing
100 Cummings Center, Suite 541J
Beverly, MA 01915-6106
Publishers at Scrivener
Martin Scrivener ([email protected])
Phillip Carmical ([email protected])
Basic Electrical and
Instrumentation Engineering
P. Sivaraman, C. Sharmeela,
A. Thaiyal Nayagi,
and R. Mahendran
This edition first published 2021 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA
and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA
© 2021 Scrivener Publishing LLC
For more information about Scrivener publications please visit www.scrivenerpublishing.com.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or
transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or other-
wise, except as permitted by law. Advice on how to obtain permission to reuse material from this title
is available at http://www.wiley.com/go/permissions.
Wiley Global Headquarters
111 River Street, Hoboken, NJ 07030, USA
For details of our global editorial offices, customer services, and more information about Wiley prod-
ucts visit us at www.wiley.com.
Limit of Liability/Disclaimer of Warranty
While the publisher and authors have used their best efforts in preparing this work, they make no rep-
resentations or warranties with respect to the accuracy or completeness of the contents of this work and
specifically disclaim all warranties, including without limitation any implied warranties of merchant-
ability or fitness for a particular purpose. No warranty may be created or extended by sales representa-
tives, written sales materials, or promotional statements for this work. The fact that an organization,
website, or product is referred to in this work as a citation and/or potential source of further informa-
tion does not mean that the publisher and authors endorse the information or services the organiza-
tion, website, or product may provide or recommendations it may make. This work is sold with the
understanding that the publisher is not engaged in rendering professional services. The advice and
strategies contained herein may not be suitable for your situation. You should consult with a specialist
where appropriate. Neither the publisher nor authors shall be liable for any loss of profit or any other
commercial damages, including but not limited to special, incidental, consequential, or other damages.
Further, readers should be aware that websites listed in this work may have changed or disappeared
between when this work was written and when it is read.
Library of Congress Cataloging-in-Publication Data
ISBN 9781119764465
Cover image: Courtesy of the Authors
Cover design by Kris Hackerott
Set in size of 11pt and Minion Pro by Manila Typesetting Company, Makati, Philippines
Printed in the USA
10 9 8 7 6 5 4 3 2 1
Dedications
Mr. P. Sivaraman dedicating to his father Mr. A. Palanisamy (deceased),
mother Mrs. P. Valarmathi, sister Mrs. P. Shanmuga Priya,
Spouse Mrs. A. Gowri and Daughter baby S. Aathira.
Dr. C. Sharmeela dedicating to her parents Mr. N.S.Chenniappan
and Mrs. C. Kasturi, my brother Chandrasekar, Vanitha,
Shakthi Chandrasekar, Subathra and my beloved friends for
encouraging me and extending their full support in writing the book.
Ms. A. Thaiyal Nayagi dedicating to her mother A.Mariyayee,
sister A. sujatha and my brother’s A.Azhagirisamy, A.saravanamani
for their constant encouragement and support.
Mr. R. Mahendran dedicating to his father, mother and sister.
Contents
Foreword xi
Acknowledgements xiii
1 Introduction to Electric Power Systems 1
1.1 Introduction 1
1.1.1 Electrical Parameters 3
1.1.1.1 Voltage 3
1.1.1.2 Current 11
1.1.1.3 Time Period and Frequency 15
1.1.1.4 Phase Angle (ɸ) 16
1.2 Three-Phase Supply Connections 17
1.2.1 Star Connection 17
1.2.2 Delta Connection 19
1.2.3 Balanced Load 21
1.2.4 Unbalanced Load 23
1.2.5 Star – Delta Conversion 23
1.2.6 Delta to Star Conversion 24
1.3 Power 25
1.3.1 Real Power or Active Power (P) 25
1.3.2 Reactive Power (Q) 28
1.3.3 Apparent Power (S) 31
1.4 Power Factor (PF) 35
1.4.1 Classification Based on Load Characteristics 35
1.4.2 Classification Based on Harmonics Producing Loads 46
1.4.3 The Need for Power Factor Improvement 47
1.4.4 Methods of Power Factor Improvement 48
1.5 Types of Loads 49
1.5.1 Linear Loads 50
1.5.2 Non-Linear Loads 50
vii
viii Contents
1.6 Three-Phase Power Measurement 50
1.7 Overview of Power Systems 56
1.7.1 Components of an Electric Power System 58
1.8 Protection of Power System 63
References 75
2 Transformers 79
2.1 Introduction 79
2.2 Transformer Magnetics 82
2.3 Construction of Transformer 85
2.4 EMF Equation of a Transformer 88
2.5 Ideal Transformer 91
2.6 Transformation Ratio (K) 95
2.7 Circuit Model or Equivalent Circuit of Transformer 96
2.8 Voltage Regulation of Transformer 100
2.9 Name Plate Rating 101
2.10 Efficiency of Transformer 102
2.11 Three-Phase Transformer 104
2.12 Components of the Transformer 113
2.13 Standards for Transformers 116
References 123
3 DC Machines 125
3.1 Introduction 125
3.1.1 DC Generators 125
3.1.2 DC Motors 125
3.1.3 Construction of DC Machines 125
3.2 Operation of DC Machines 132
3.2.1 Principle of DC Generators 132
3.2.2 Operating Principle of Motors 133
3.3 EMF Equation of DC Generator 136
3.4 Torque Equation of a DC Motor 138
3.5 Circuit Model 139
3.5.1 Generator Mode 140
3.5.2 Motor Mode 141
3.5.3 Symbolic Representation of DC Generator 141
3.6 Methods of Excitation 142
3.7 Characteristics of DC Generator 148
3.7.1 Characteristics of Separately Excited
DC Generator 150
3.7.2 Load Characteristics of DC Shunt Generator 152
Contents ix
3.7.3 Load Characteristics of DC Series Generator 154
3.7.4 Load Characteristics of DC Compound Generator 155
3.8 Types of DC Motor 156
3.9 DC Motor Characteristics 160
3.10 Necessity for Starters 165
3.11 Speed Control of DC Motors 170
3.12 Universal Motor 179
References 183
4 AC Machines 185
4.1 Introduction 185
4.2 Three-Phase Induction Motor 185
4.2.1 Rotating Magnetic Field 186
4.2.2 Construction 186
4.2.3 Working Principle 189
4.2.4 Slip of an Induction Motor 192
4.2.5 Torque Equation 193
4.2.6 Torque–Slip Characteristics 195
4.2.7 Induction Motor as a Transformer 197
4.2.8 Equivalent Circuit of Induction Motor 198
4.3 Single-Phase Induction Motor 201
4.3.1 Introduction 201
4.3.2 Working Principle 203
4.3.3 Types of Single-Phase Induction Motor 203
4.4 Starting Methods of Induction Motor 209
4.4.1 Need for Starters 209
4.4.2 Types of Starters 209
4.5 Speed Control of Three-Phase Induction Motor 215
4.6 Synchronous Motor 220
4.6.1 Construction 220
4.6.2 Features of a Synchronous Motor 220
4.6.3 Working Principle 221
4.6.4 Starting Methods of Synchronous Motor 221
4.6.5 Torque Equation of Synchronous Motor 222
4.7 Stepper Motor 223
4.8 Brushless DC (BLDC) Motor 225
4.8.1 Construction 225
4.8.2 Working Principle 226
4.9 Alternator 226
4.9.1 Construction 226
4.9.2 Working Principle 229
x Contents
4.9.3 EMF Equation of an Alternator 232
4.9.4 Voltage Regulation of an Alternator 234
4.10 Standards for Electric Machines 235
References 241
5 Measurement and Instrumentation 243
5.1 Electrical and Electronic Instruments 243
5.1.1 Classification of Instruments 243
5.1.2 Basic Requirements for Measurement 250
5.1.3 Types of Indicating Instruments 259
5.1.4 AC Indicating Instruments 270
5.1.5 Electrical Instruments 275
5.2 Cathode Ray Oscilloscope (CRO) 278
5.3 Digital Storage Oscilloscope 283
5.4 Static and Dynamic Characteristics of Measurements 289
5.4.1 Static Characteristics 289
5.4.2 Dynamic Characteristics 296
5.5 Measurement of Errors 297
5.5.1 Types of Errors 298
5.6 Transducer 300
5.6.1 Classification of Transducers 302
References 338
Index 341