Electrical Engineering: Electric Machines
This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA
Overview
Download & View Electrical Engineering: Electric Machines as PDF for free.
More details
- Words: 1,170
- Pages: 14
Loading documents preview...
Electrical Engineering
Electric Machines Comprehensive Theory with Solved Examples and Practice Questions
Publications
Publications
MADE EASY Publications Corporate Office: 44-A/4, Kalu Sarai (Near Hauz Khas Metro Station), New Delhi-110016 E-mail: [email protected] Contact: 011-45124660, 8860378007 Visit us at: www.madeeasypublications.org
Electric Machines © Copyright by MADE EASY Publications. All rights are reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photo-copying, recording or otherwise), without the prior written permission of the above mentioned publisher of this book.
First Edition : 2015 Second Edition : 2016 Third Edition: 2017 Fourth Edition: 2018
© All rights reserved by MADE EASY PUBLICATIONS. No part of this book may be reproduced or utilized in any form without the written permission from the publisher.
Contents Electric Machines Chapter 1
2.18 Losses and Efficiency................................................................36
Magnetic Circuits����������������������������������������������� 1
2.19 Transformer Efficiency..............................................................36
1.1
Magnetic Circuits........................................................... 1
2.20 Losses ............................................................................................37
1.2
Leakage Flux.................................................................... 5
2.21 Maximum Efficiency..................................................................38
1.3 Fringing.............................................................................. 6
2.22 h Considerations in Power Transformer & Distribution
Induced EMF.................................................................... 6
Transformer..................................................................................45
Student Assignments-1................................................. 7
2.23 All Day Efficiency........................................................................45
Student Assignments-2................................................. 8
2.24 Auto Transformer.......................................................................48
1.4.
2.25 Tertiary Winding.........................................................................52
Chapter 2
2.26 3-Phase Transformers...............................................................55
Transformer��������������������������������������������������������10
2.27 3-Phase Transformer Connections.......................................56
2.1 Operating Principle...................................................................10
2.28 Open Delta or V Connection..................................................62
2.2 Primary and Secondary............................................................11
2.29 3-f to 2-f Conversion (Scott Connection).........................64
2.3 Linked Electric and Magnetic Circuits in Power
2.30 Parallel Operation of Transformer........................................66
Transformers................................................................................11
2.31 Load Sharing................................................................................67
2.4 E.m.f. Equation of Transformer..............................................13
2.32 Magnetizing Current Phenomenon....................................73
2.5 Ampere-turns Relation.............................................................14
Student Assignments-1..............................................................76
2.6 Leakage Reactance....................................................................16
Student Assignments-2..............................................................80
2.7 Ideal Transformer.......................................................................16
Chapter 3
2.8 Exact Equivalent Circuit of a Transformer..........................20
Direct Current Machine��������������������������������84
2.9 Complete Phasor Diagram of Step Down Transformer
3.1 Basic of Electric Machines.......................................................84
[N1 > N2]..........................................................................................21
3.2 D.C. Machine Construction....................................................84
2.10 Equivalent Circuit Referred to Primary Side.....................22
3.3 Magnetic Circuit of A D.C. Generator..................................85
2.11 Equivalent Circuit Referred to Secondary Side................22
3.4 Equivalent Circuit of A D.C. Machine Armature...................85
2.12 Approximate Equivalent Circuit Referred to Primary....24
3.5 Types of D.C. Machine..............................................................86
2.13 Approximate Equivalent Circuit Referred to
3.6 Direct Current Machines Operation....................................86
Secondary Side...........................................................................25
3.7 E.M.F. Equation of D.C. Machine...........................................87
2.14 Final Approximate Equivalent Circuit.................................25
3.8. (i) Types of Armature Windings............................................89
2.15 Per Unit Value..............................................................................25
3.8. (ii) Lap and Wave Windings.....................................................89
2.16 Testing of Transformers............................................................27
3.9 Methods of Excitation..............................................................90
2.17 Voltage Regulation....................................................................32
3.10 Electromagnetic Torque Equation.......................................91
(iii)
3.11 Classification of Direct Current Machines...........92
4.15 (A) Effect of Change in Excitation at Constant (KW)
3.12 Power Balance in Direct Current Machine...........92
3.13 Separately Excited Machine (VBD Neglected)...93
4.15 (B) Effect of Change in Load (KW) at Constant
3.14 Shunt Excited Machine..............................................93
Excitation................................................................................... 182
3.15 Long Shunt Generator................................................94
4.16 V-Curve....................................................................................... 184
3.16 Short Shunt Generator...............................................94
4.17 Compounding Curve............................................................. 184
3.17 Condition for Maximum Power Transfer..............94
3.18 Maximum Efficiency....................................................96
3.19 Armature Reaction.......................................................99
4.18 Synchronous Condenser...................................................... 188 4.19 Transition From Generator to Motor Action.................. 190 4.20 Prime-Mover Characteristics............................................... 192
3.20 Commutation............................................................. 100
Load ......................................................................................... 181
4.21 Parallel Operation of Alternators....................................... 193
3.21 Compensating Winding.......................................... 102
4.22 Synchronizing Procedure..................................................... 194
3.22 Interpoles..................................................................... 104
4.23 Synchronizing by A Synchroscope................................... 196
3.23 Operating Characteristic of D.C. Generators... 106
3.24 Operating Characteristics of D.C. Motors......... 115
4.24 Operation of Generator........................................................ 197
3.25 Starting of D.C. Motors............................................ 121
4.25 Starting of Synchronous Motors........................................ 201
3.26 Three-Point D.C. Shunt Motor Starter................ 121
4.26 Hunting or Phase Swinging................................................. 201
3.27 Four-Point Starter...................................................... 122
4.27 Comparison between 3-Phase Synchronous and
3.28 D.C. Shunt Motor Starter Design......................... 123
3.29 Speed Control of D.C. Motors............................... 126
4.28 Applications of Synchronous Motors.............................. 203
3.30 Testing of D.C. Machines......................................... 132
4.29 Salient Pole Machines............................................................ 204
3.31 Electric Braking of D.C. Motors............................. 136
Student Assignments-1........................................................... 211
3.32 Types of Electric Braking......................................... 136
Student Assignments-2........................................................... 216
3.33 Present–Day Uses of D.C. Machines.................... 140
Induction Motors.................................................................... 203
Student Assignments-1............................................ 140
Chapter 5
Student Assignments-2............................................ 145
3-f Induction Machine.........................220
Chapter 4
5.1 Stator ......................................................................................... 220 5.2 Rotor ......................................................................................... 221
Synchronous Machine��������������������������������149
5.3 Induction Motor as a Transformer..................................... 221
4.1 Advantages of Rotating Field Alternator........................ 150
5.4 Difference between IM and Transformer........................ 222
4.2 Construction of Three-Phase Synchronous Machines.150
5.5 MMF Induced in IM................................................................. 222
4.3 Speed and Frequency............................................................ 152
5.6 Principle of Operation........................................................... 224
4.4 Excitation Systems for Synchronous Machines............ 154
5.7 Frequency of Induced emf................................................... 224
4.5 Voltage Generation................................................................ 155
5.8 Stator Fed Induction Motor................................................. 225
4.6 E.m.f. Equation of Alternator............................................... 156
5.9 Rotor Fed Induction Motor.................................................. 228
4.7 Armature Windings................................................................ 157
5.10 Equivalent Circuit of 3-f Induction Motor...................... 228
4.8 Flux and Mmf Phasors in Synchronous Machines....... 166
5.11 Exact Equivalent Circuit Referred to Stator.................... 229
4.9 Synchronous Machine Phasor Diagram.......................... 170
5.12 Power Flow in 3-f Induction Motor................................... 230
4.10 Open Circuit Characteristics................................................ 172
5.13 Power Flow according to Steinmetz Model................... 231
4.11 Short Circuit Characteristics................................................ 173
5.14 Computational Convenience in Steinmetz Model...... 231
4.12 Zero Power Factor Characteristics..................................... 173
5.15 Thevenin’s Equivalent of 3-f Induction Motor
4.13 Methods to Determine Voltage Regulation.................. 175
4.14 Power Angle Equation........................................................... 179
(iv)
(Steinmetz Model).................................................................. 232
5.16 For Low Slip Region (Normal Operating Region)........ 233
6.11 A - Torques Vs Pulse Rate...................................................... 288
5.17 For High Slip Region (Starting Region or Braking
6.11 B - Different Types of Torque............................................... 288
Region)........................................................................................ 234
6.12 Series Motor-Universal Motor............................................. 289
5.18 Maximum Torque or Breakdown Torque or Pull out
Student Assignments-1........................................................... 290
Student Assignments-2........................................................... 291
Torque or Stalling Torque..................................................... 235
5.19 Slip at Maximum Torque....................................................... 235
Chapter 7
5.20 Determination of Equivalent Circuit from No-load & 5.21 Circle Diagram.......................................................................... 241
Basic Concept of Rotating Electric Machines���������������������������������������������������������� 293
5.22 Construction of Circle Diagram.......................................... 241
7.1 Basic Structure of Rotating Electric Machines.............. 293
5.23 Performance Characteristics (load) of Induction
7.2 Electromotive Force Generated by Rotation of a Coil...... 294
7.3 Conversion of Alternating emf to Unidirectional Voltage
Blocked Rotor Tests................................................................ 239
Motor ......................................................................................... 245
5.24 Starters........................................................................................ 246
5.25 Magnetic Locking (Cogging).............................................. 251
7.4 D.C. Machine............................................................................. 295
5.26 Crawling..................................................................................... 252
7.5 Induction Machine................................................................. 295
5.27 Deep Bar Rotor......................................................................... 254
7.6 Synchronous Machine........................................................... 295
5.28 Starting Technique of Slip-Ring Induction Motor....... 255
7.7 MMF Space Wave of A Concentrated Coil...................... 296
5.29 Speed Control of Induction Motor.................................... 256
7.8 MMF of Distributed Single-Phase Winding................... 297
5.30 Double Cage Motor................................................................ 260
7.9 Mmf of Three-Phase Windings, Rotating Magnetic
5.31 Induction Generator.............................................................. 261
Student Assignments-1........................................................... 263
Student Assignments-2........................................................... 267
using Commutator Segments............................................ 294
Field ......................................................................................... 298
7.10 Generated Voltages in AC Machines................................ 300 7.11 Machine Torques..................................................................... 301
Chapter 6
Student Assignments............................................................... 304
Chapter 8
Fractional Kilowatt Motors..................272
Miscellaneous������������������������������������������������ 305
6.1 Single-Phase Induction Motors......................................... 272
8.1 Classification of Transformer Protection......................... 305
6.2 Double Revolving Field Theory.......................................... 273
8.2 Buchholz System..................................................................... 306
6.3 Equivalent Circuit.................................................................... 275
8.3 Windings and Insulation....................................................... 308
6.4 Split-Phase Motors.................................................................. 279
8.4 Instrument Transformer........................................................ 313
6.5 Types of Capacitor Split-Phase Motors............................ 280
8.5 Current Transformer (CT)...................................................... 313
6.6 Shaded-Pole Motor................................................................. 282
8.6 Voltage Transformer (VT) or Potential
6.7 Applications.............................................................................. 283
6.8 Single-Phase Synchronous Motors................................... 283
Transformer (PT)...................................................................... 315
8.7 Transformer Cooling.............................................................. 315
6.9 Two-Phase Servomotor......................................................... 285
8.8 Conservator and Breather.................................................... 316
6.10 Stepper Motors........................................................................ 286
8.9 Rating of the Transformer.................................................... 316
6.11 Types of Stepper Motors...................................................... 287
nnnn
(v)
Electric Machines Comprehensive Theory with Solved Examples and Practice Questions
Publications
Publications
MADE EASY Publications Corporate Office: 44-A/4, Kalu Sarai (Near Hauz Khas Metro Station), New Delhi-110016 E-mail: [email protected] Contact: 011-45124660, 8860378007 Visit us at: www.madeeasypublications.org
Electric Machines © Copyright by MADE EASY Publications. All rights are reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photo-copying, recording or otherwise), without the prior written permission of the above mentioned publisher of this book.
First Edition : 2015 Second Edition : 2016 Third Edition: 2017 Fourth Edition: 2018
© All rights reserved by MADE EASY PUBLICATIONS. No part of this book may be reproduced or utilized in any form without the written permission from the publisher.
Contents Electric Machines Chapter 1
2.18 Losses and Efficiency................................................................36
Magnetic Circuits����������������������������������������������� 1
2.19 Transformer Efficiency..............................................................36
1.1
Magnetic Circuits........................................................... 1
2.20 Losses ............................................................................................37
1.2
Leakage Flux.................................................................... 5
2.21 Maximum Efficiency..................................................................38
1.3 Fringing.............................................................................. 6
2.22 h Considerations in Power Transformer & Distribution
Induced EMF.................................................................... 6
Transformer..................................................................................45
Student Assignments-1................................................. 7
2.23 All Day Efficiency........................................................................45
Student Assignments-2................................................. 8
2.24 Auto Transformer.......................................................................48
1.4.
2.25 Tertiary Winding.........................................................................52
Chapter 2
2.26 3-Phase Transformers...............................................................55
Transformer��������������������������������������������������������10
2.27 3-Phase Transformer Connections.......................................56
2.1 Operating Principle...................................................................10
2.28 Open Delta or V Connection..................................................62
2.2 Primary and Secondary............................................................11
2.29 3-f to 2-f Conversion (Scott Connection).........................64
2.3 Linked Electric and Magnetic Circuits in Power
2.30 Parallel Operation of Transformer........................................66
Transformers................................................................................11
2.31 Load Sharing................................................................................67
2.4 E.m.f. Equation of Transformer..............................................13
2.32 Magnetizing Current Phenomenon....................................73
2.5 Ampere-turns Relation.............................................................14
Student Assignments-1..............................................................76
2.6 Leakage Reactance....................................................................16
Student Assignments-2..............................................................80
2.7 Ideal Transformer.......................................................................16
Chapter 3
2.8 Exact Equivalent Circuit of a Transformer..........................20
Direct Current Machine��������������������������������84
2.9 Complete Phasor Diagram of Step Down Transformer
3.1 Basic of Electric Machines.......................................................84
[N1 > N2]..........................................................................................21
3.2 D.C. Machine Construction....................................................84
2.10 Equivalent Circuit Referred to Primary Side.....................22
3.3 Magnetic Circuit of A D.C. Generator..................................85
2.11 Equivalent Circuit Referred to Secondary Side................22
3.4 Equivalent Circuit of A D.C. Machine Armature...................85
2.12 Approximate Equivalent Circuit Referred to Primary....24
3.5 Types of D.C. Machine..............................................................86
2.13 Approximate Equivalent Circuit Referred to
3.6 Direct Current Machines Operation....................................86
Secondary Side...........................................................................25
3.7 E.M.F. Equation of D.C. Machine...........................................87
2.14 Final Approximate Equivalent Circuit.................................25
3.8. (i) Types of Armature Windings............................................89
2.15 Per Unit Value..............................................................................25
3.8. (ii) Lap and Wave Windings.....................................................89
2.16 Testing of Transformers............................................................27
3.9 Methods of Excitation..............................................................90
2.17 Voltage Regulation....................................................................32
3.10 Electromagnetic Torque Equation.......................................91
(iii)
3.11 Classification of Direct Current Machines...........92
4.15 (A) Effect of Change in Excitation at Constant (KW)
3.12 Power Balance in Direct Current Machine...........92
3.13 Separately Excited Machine (VBD Neglected)...93
4.15 (B) Effect of Change in Load (KW) at Constant
3.14 Shunt Excited Machine..............................................93
Excitation................................................................................... 182
3.15 Long Shunt Generator................................................94
4.16 V-Curve....................................................................................... 184
3.16 Short Shunt Generator...............................................94
4.17 Compounding Curve............................................................. 184
3.17 Condition for Maximum Power Transfer..............94
3.18 Maximum Efficiency....................................................96
3.19 Armature Reaction.......................................................99
4.18 Synchronous Condenser...................................................... 188 4.19 Transition From Generator to Motor Action.................. 190 4.20 Prime-Mover Characteristics............................................... 192
3.20 Commutation............................................................. 100
Load ......................................................................................... 181
4.21 Parallel Operation of Alternators....................................... 193
3.21 Compensating Winding.......................................... 102
4.22 Synchronizing Procedure..................................................... 194
3.22 Interpoles..................................................................... 104
4.23 Synchronizing by A Synchroscope................................... 196
3.23 Operating Characteristic of D.C. Generators... 106
3.24 Operating Characteristics of D.C. Motors......... 115
4.24 Operation of Generator........................................................ 197
3.25 Starting of D.C. Motors............................................ 121
4.25 Starting of Synchronous Motors........................................ 201
3.26 Three-Point D.C. Shunt Motor Starter................ 121
4.26 Hunting or Phase Swinging................................................. 201
3.27 Four-Point Starter...................................................... 122
4.27 Comparison between 3-Phase Synchronous and
3.28 D.C. Shunt Motor Starter Design......................... 123
3.29 Speed Control of D.C. Motors............................... 126
4.28 Applications of Synchronous Motors.............................. 203
3.30 Testing of D.C. Machines......................................... 132
4.29 Salient Pole Machines............................................................ 204
3.31 Electric Braking of D.C. Motors............................. 136
Student Assignments-1........................................................... 211
3.32 Types of Electric Braking......................................... 136
Student Assignments-2........................................................... 216
3.33 Present–Day Uses of D.C. Machines.................... 140
Induction Motors.................................................................... 203
Student Assignments-1............................................ 140
Chapter 5
Student Assignments-2............................................ 145
3-f Induction Machine.........................220
Chapter 4
5.1 Stator ......................................................................................... 220 5.2 Rotor ......................................................................................... 221
Synchronous Machine��������������������������������149
5.3 Induction Motor as a Transformer..................................... 221
4.1 Advantages of Rotating Field Alternator........................ 150
5.4 Difference between IM and Transformer........................ 222
4.2 Construction of Three-Phase Synchronous Machines.150
5.5 MMF Induced in IM................................................................. 222
4.3 Speed and Frequency............................................................ 152
5.6 Principle of Operation........................................................... 224
4.4 Excitation Systems for Synchronous Machines............ 154
5.7 Frequency of Induced emf................................................... 224
4.5 Voltage Generation................................................................ 155
5.8 Stator Fed Induction Motor................................................. 225
4.6 E.m.f. Equation of Alternator............................................... 156
5.9 Rotor Fed Induction Motor.................................................. 228
4.7 Armature Windings................................................................ 157
5.10 Equivalent Circuit of 3-f Induction Motor...................... 228
4.8 Flux and Mmf Phasors in Synchronous Machines....... 166
5.11 Exact Equivalent Circuit Referred to Stator.................... 229
4.9 Synchronous Machine Phasor Diagram.......................... 170
5.12 Power Flow in 3-f Induction Motor................................... 230
4.10 Open Circuit Characteristics................................................ 172
5.13 Power Flow according to Steinmetz Model................... 231
4.11 Short Circuit Characteristics................................................ 173
5.14 Computational Convenience in Steinmetz Model...... 231
4.12 Zero Power Factor Characteristics..................................... 173
5.15 Thevenin’s Equivalent of 3-f Induction Motor
4.13 Methods to Determine Voltage Regulation.................. 175
4.14 Power Angle Equation........................................................... 179
(iv)
(Steinmetz Model).................................................................. 232
5.16 For Low Slip Region (Normal Operating Region)........ 233
6.11 A - Torques Vs Pulse Rate...................................................... 288
5.17 For High Slip Region (Starting Region or Braking
6.11 B - Different Types of Torque............................................... 288
Region)........................................................................................ 234
6.12 Series Motor-Universal Motor............................................. 289
5.18 Maximum Torque or Breakdown Torque or Pull out
Student Assignments-1........................................................... 290
Student Assignments-2........................................................... 291
Torque or Stalling Torque..................................................... 235
5.19 Slip at Maximum Torque....................................................... 235
Chapter 7
5.20 Determination of Equivalent Circuit from No-load & 5.21 Circle Diagram.......................................................................... 241
Basic Concept of Rotating Electric Machines���������������������������������������������������������� 293
5.22 Construction of Circle Diagram.......................................... 241
7.1 Basic Structure of Rotating Electric Machines.............. 293
5.23 Performance Characteristics (load) of Induction
7.2 Electromotive Force Generated by Rotation of a Coil...... 294
7.3 Conversion of Alternating emf to Unidirectional Voltage
Blocked Rotor Tests................................................................ 239
Motor ......................................................................................... 245
5.24 Starters........................................................................................ 246
5.25 Magnetic Locking (Cogging).............................................. 251
7.4 D.C. Machine............................................................................. 295
5.26 Crawling..................................................................................... 252
7.5 Induction Machine................................................................. 295
5.27 Deep Bar Rotor......................................................................... 254
7.6 Synchronous Machine........................................................... 295
5.28 Starting Technique of Slip-Ring Induction Motor....... 255
7.7 MMF Space Wave of A Concentrated Coil...................... 296
5.29 Speed Control of Induction Motor.................................... 256
7.8 MMF of Distributed Single-Phase Winding................... 297
5.30 Double Cage Motor................................................................ 260
7.9 Mmf of Three-Phase Windings, Rotating Magnetic
5.31 Induction Generator.............................................................. 261
Student Assignments-1........................................................... 263
Student Assignments-2........................................................... 267
using Commutator Segments............................................ 294
Field ......................................................................................... 298
7.10 Generated Voltages in AC Machines................................ 300 7.11 Machine Torques..................................................................... 301
Chapter 6
Student Assignments............................................................... 304
Chapter 8
Fractional Kilowatt Motors..................272
Miscellaneous������������������������������������������������ 305
6.1 Single-Phase Induction Motors......................................... 272
8.1 Classification of Transformer Protection......................... 305
6.2 Double Revolving Field Theory.......................................... 273
8.2 Buchholz System..................................................................... 306
6.3 Equivalent Circuit.................................................................... 275
8.3 Windings and Insulation....................................................... 308
6.4 Split-Phase Motors.................................................................. 279
8.4 Instrument Transformer........................................................ 313
6.5 Types of Capacitor Split-Phase Motors............................ 280
8.5 Current Transformer (CT)...................................................... 313
6.6 Shaded-Pole Motor................................................................. 282
8.6 Voltage Transformer (VT) or Potential
6.7 Applications.............................................................................. 283
6.8 Single-Phase Synchronous Motors................................... 283
Transformer (PT)...................................................................... 315
8.7 Transformer Cooling.............................................................. 315
6.9 Two-Phase Servomotor......................................................... 285
8.8 Conservator and Breather.................................................... 316
6.10 Stepper Motors........................................................................ 286
8.9 Rating of the Transformer.................................................... 316
6.11 Types of Stepper Motors...................................................... 287
nnnn
(v)
Related Documents
Electrical Engineering: Electric Machines
January 2021 1
Bible Electrical Control For Machines
January 2021 1
Bible Electrical Control For Machines
January 2021 1
Mcq In Ac Electrical Machines
February 2021 1
Basic Electrical Engineering
January 2021 3
Electrical Engineering Training.pdf
January 2021 1More Documents from "frangarcia1979"