Drives and Control (2009 Edition) by Chinttan Size : A4, Pages: 432; Price : Rs. 298.00 Buy this book from : www.chinttanpublications.in

2. Table of contents iii
Contents
Preface xi
Acknowledgements xii
Dedication xiii
Roadmap to the syllabus xiv
1 DC MACHINES ................................................................................ [1-1 to 1-56]
1.1 CONSTRUCTION OF DC MACHINES.............................................................................[1-1]
1.2 TYPES OF ARMATURE WINDING..................................................................................[1-4]
1.3 TYPES OF DC MACHINES..............................................................................................[1-5]
1.3.1 DC generator ......................................................................................................................... [1-6]
1.3.1.1 Types of DC generator....................................................................................... [1-9]
1.3.2 Principles and working of DC motors .................................................................................. [1-15]
1.3.2.1 Types of DC motors......................................................................................... [1-17]
1.3.2.2 Characteristics of DC shunt motor................................................................... [1-19]
1.3.2.3 Characteristics of DC series motor .................................................................. [1-21]
1.3.2.4 Characteristics of compound motor................................................................. [1-22]
1.3.2.5 Speed of a DC motor ....................................................................................... [1-24]
1.3.3 Power stages in DC motors................................................................................................. [1-28]
1.3.4 Power stages in DC generator ............................................................................................ [1-29]
1.3.5 Speed control of shunt motors ............................................................................................ [1-30]
1.3.6 Series motor speed control ................................................................................................. [1-32]
1.4 MOTORING MODES......................................................................................................[1-33]
1.5 TRANSFER FUNCTION OF DC MOTORS ....................................................................[1-35]
1.5.1 Mathematical model of DC motor........................................................................................ [1-39]
1.5.2 Speed control system of DC motor ..................................................................................... [1-40]
1.6 NECESSITY OF A STARTER ........................................................................................[1-42]
1.6.1 Shunt motor and compound motor starters......................................................................... [1-43]

3. Table of contentsiv
1.6.2 Series motor starters ........................................................................................................... [1-45]
1.7 DC MOTOR APPLICATIONS.........................................................................................[1-47]
Solved University Examples............................................................................................................ [1-48]
Review Questions............................................................................................................................. [1-55]
2 AC MACHINES ................................................................................ [2-1 to 2-80]
2.1 CLASSIFICATION OF A-C MOTORS..............................................................................[2-1]
2.1.1 Classification based on the type of current ........................................................................... [2-2]
2.1.2 Classification of AC motors based on their speed ................................................................ [2-2]
2.1.3 Classification based on their structural features ................................................................... [2-2]
2.2 INDUCTION MOTOR (ROTATING MAGNETIC FIELD)...................................................[2-2]
2.2.1 Construction of induction motors........................................................................................... [2-2]
2.2.2 Squirrel – cage rotor.............................................................................................................. [2-3]
2.2.3 Phase wounded rotor ............................................................................................................ [2-4]
2.2.4 Rotating magnetic field theory............................................................................................... [2-4]
2.2.5 Frequency of rotor current..................................................................................................... [2-8]
2.2.6 Relation between torque and rotor power factor ................................................................... [2-8]
2.2.7 Starting torque..................................................................................................................... [2-10]
2.2.8 Relation between torque and slip or torque slip characteristics.......................................... [2-10]
2.2.9 Power stages in an induction motors .................................................................................. [2-12]
2.2.10 Torque, mechanical power and rotor output loss ................................................................ [2-12]
2.2.11 Methods of speed control of three phase induction motors ............................................... [2-14]
2.2.12 Starters for the three phase induction motors .................................................................... [2-16]
2.3 AC POSITION CONTROL SYSTEM ..............................................................................[2-18]
2.4 UNIVERSITY SOLVED EXAMPLES ON INDUCTION MOTORS...................................[2-20]
2.5 INTRODUCTION TO SYNCHRONOUS MACHINE ........................................................[2-25]
2.6 CLASSIFICATION OF ALTERNATORS ........................................................................[2-26]
2.7 ALTERNATOR CONSTRUCTION .................................................................................[2-27]
2.8 PROVISIONS FOR VENTILATION ................................................................................[2-30]
2.9 FREQUENCY OF INDUCED E.M.F................................................................................[2-30]
2.10 SYNCHRONOUS SPEED ..............................................................................................[2-31]
2.11 ARMATURE WINDINGS................................................................................................[2-31]
2.12 CLASSIFICATION OF ARMATURE WINDINGS............................................................[2-32]
2.13 SINGLE-PHASE ARMATURE WINDINGS.....................................................................[2-32]
2.14 SIMPLE THREE-PHASE ARMATURE WINDINGS........................................................[2-34]
2.15 E.M.F. EQUATION OF AN ALTERNATOR....................................................................[2-36]
2.15.1 Effect of distributing the winding on induced E.M.F. ........................................................... [2-37]

4. Table of contents v
2.15.2 Effect of using fractional-pitch coils on induced E.M.F........................................................ [2-40]
2.15.3 General expression for the E.M.F. of an alternator ............................................................. [2-42]
2.16 ARMATURE REACTION................................................................................................[2-45]
2.17 PARAMETERS OF ARMATURE WINDING...................................................................[2-49]
2.18 CONCEPT OF SYNCHRONOUS REACTANCE AND IMPEDANCE .............................[2-49]
2.19 PHASOR DIAGRAMS OF AN ALTERNATOR ON LOAD .............................................[2-51]
2.20 VOLTAGE REGULATION OF AN ALTERNATOR.........................................................[2-55]
2.21 DETERMINATION OF VOLTAGE REGULATION..........................................................[2-56]
2.21.1 Voltage regulation by direct loading method ....................................................................... [2-56]
2.21.2 Voltage regulation by synchronous impedance method or electromotive force ................. [2-57]
University Solved examples on alternators ...................................................................................... [2-64]
Review Questions............................................................................................................................. [2-77]
3 SPECIAL PURPOSE MACHINES............................................. [3-1 to 3-30]
3.1 INTRODUCTION ..............................................................................................................[3-1]
3.2 CLASSIFICATION OF SINGLE-PHASE MOTORS..........................................................[3-2]
3.3 SINGLE-PHASE INDUCTION MOTORS..........................................................................[3-2]
3.4 TYPES OF SINGLE-PHASE INDUCTION MOTORS .......................................................[3-5]
3.4.1 Resistance split-phase motors .............................................................................................. [3-5]
3.4.2 Capacitor split-phase motors................................................................................................. [3-6]
3.4.3 Shaded-pole motors .............................................................................................................. [3-9]
3.5 SINGLE-PHASE SYNCHRONOUS MOTORS ...............................................................[3-10]
3.5.1 Reluctance motors............................................................................................................... [3-11]
3.5.2 Hysteresis motors................................................................................................................ [3-12]
3.6 SINGLE-PHASE COMMUTATOR MOTORS .................................................................[3-13]
3.6.1 Single-phase A.C. series motors......................................................................................... [3-14]
3.6.2 Universal motors.................................................................................................................. [3-16]
3.7 STEPPER MOTORS ......................................................................................................[3-18]
3.7.1 Types of Stepper Motors ..................................................................................................... [3-18]
3.7.2 Characteristics of stepper motor ......................................................................................... [3-23]
3.7.3 Application of stepper motors.............................................................................................. [3-26]
3.8 SERVOMOTORS ...........................................................................................................[3-26]
3.8.1 Features of Servomotors..................................................................................................... [3-26]
3.8.2 Types of Servomotors ......................................................................................................... [3-26]
Review Questions............................................................................................................................. [3-28]
4 POWER DEVICES........................................................................... [4-1 to 4-76]

5. Table of contentsvi
4.1 SCR..................................................................................................................................[4-1]
4.1.1 Construction .......................................................................................................................... [4-2]
4.1.2 Operation of SCR .................................................................................................................. [4-3]
4.1.3 Steady state characteristics .................................................................................................. [4-4]
4.1.4 SCR Ratings.......................................................................................................................... [4-6]
4.1.4.1 Voltage ratings ................................................................................................... [4-8]
4.1.4.2 Current ratings ................................................................................................... [4-9]
4.1.4.3 Power ratings ................................................................................................... [4-10]
4.1.4.4 Temperature ratings......................................................................................... [4-11]
4.1.5 Gate characteristics............................................................................................................. [4-12]
4.1.6 Triggering Techniques......................................................................................................... [4-15]
4.1.6.1 Resistance firing circuit.................................................................................... [4-16]
4.1.6.2 Resistance capacitance firing circuit................................................................ [4-17]
4.2 COMMUTATION (SCR TURN–OFF METHODS) ...........................................................[4-20]
4.2.1 Natural commutation ........................................................................................................... [4-20]
4.2.2 Forced commutation............................................................................................................ [4-21]
4.3 CLASSIFICATION OF FORCED COMMUTATION METHODS .....................................[4-21]
4.3.1 Class A: self commutated by resonating the load ............................................................... [4-21]
4.3.2 Class B - self commutation by an LC circuit........................................................................ [4-23]
4.3.3 Class C - complimentary voltage commutation................................................................... [4-25]
4.3.4 Class D – auxiliary voltage commutation ............................................................................ [4-28]
4.3.5 Class E – external pulse source for commutation............................................................... [4-32]
4.3.6 Class F commutation: (Line commutation).......................................................................... [4-33]
4.3.7 Auxiliary current commutation (Class D)............................................................................. [4-34]
4.4 COMPARISON BETWEEN CLASS B AND CLASS C COMMUTATION CIRCUITS .....[4-36]
4.5 SERIES OPERATION OF THYRISTORS .....................................................................[4-40]
4.6 PARALLEL OPERATION OF THYRISTORS.................................................................[4-42]
4.7 TRIGGERING OF SERIES CONNECTED THYRISTORS ..............................................[4-42]
4.7.1 Simultaneous triggering....................................................................................................... [4-43]
4.7.2 Sequential triggering............................................................................................................ [4-44]
4.7.3 Optical triggering ................................................................................................................. [4-45]
4.8 TRIGGERING OF THYRISTORS IN PARALLEL...........................................................[4-46]
4.9 TRIAC ............................................................................................................................[4-46]
4.9.1 Construction ........................................................................................................................ [4-47]
4.9.2 Operation............................................................................................................................. [4-48]
4.9.3 Triggering modes................................................................................................................. [4-48]
4.9.4 Steady – state characteristics ............................................................................................. [4-50]
4.10 DIAC...............................................................................................................................[4-51]
4.10.1 Principle of DIAC ................................................................................................................. [4-51]

6. Table of contents vii
4.10.2 Phase control using DIAC – TRIAC .................................................................................... [4-52]
4.11 POWER MOSFET ..........................................................................................................[4-53]
4.11.1 Construction ........................................................................................................................ [4-53]
4.11.2 Operation............................................................................................................................. [4-54]
4.11.3 Static characteristics of power MOSFET............................................................................. [4-55]
4.11.4 Switching characteristics of power MOSFET ...................................................................... [4-56]
4.11.4.1 Turn on characteristics..................................................................................... [4-56]
4.11.4.2 Turn off characteristics..................................................................................... [4-57]
4.11.5 Safe operating Area (SOA) ................................................................................................. [4-58]
4.11.6 Parallel operation................................................................................................................. [4-58]
4.11.7 Comparison of power MOSFET with power BJT ................................................................ [4-59]
4.12 INSULATE GATE BIPOLAR TRANSISTOR (IGBT) ......................................................[4-59]
4.12.1 Construction ........................................................................................................................ [4-59]
4.12.2 Operation............................................................................................................................. [4-61]
4.12.3 Steady state characteristics of IGBT................................................................................... [4-62]
4.12.4 Switching characteristics of IGBT........................................................................................ [4-63]
4.12.5 Safe operating area (SOA).................................................................................................. [4-64]
4.12.6 Application of IGBT.............................................................................................................. [4-65]
4.12.7 Comparison of Power MOSFETs and IGBTs...................................................................... [4-65]
4.13 UNIJUNCTION TRANSISTOR (UJT) .............................................................................[4-65]
4.13.1 Construction ........................................................................................................................ [4-65]
4.13.2 Equivalent Circuit of a UJT.................................................................................................. [4-67]
4.13.3 Characteristics of UJT ......................................................................................................... [4-68]
4.13.4 UJT relaxation oscillator ...................................................................................................... [4-69]
4.13.5 UJT relaxation oscillator for pulse outputs .......................................................................... [4-70]
4.13.6 Triggering using UJT ........................................................................................................... [4-71]
4.13.7 Phase control using pedestal and ramp triggering.............................................................. [4-72]
Review Questions............................................................................................................................. [4-74]
5 CONTROLLED RECTIFIERS.................................................... [5-1 to 5-108]
5.1 INTRODUCTION ..............................................................................................................[5-1]
5.2 PHASE CONTROLLED RECTIFIERS (AC – DC CONVERTER) .....................................[5-2]
5.2.1 Concept of line and forced commutation............................................................................... [5-2]
5.2.2 Classification of rectifiers....................................................................................................... [5-2]
5.2.3 Classification of phase controlled converters........................................................................ [5-3]
5.2.4 Principle of phase controlled converter operation ................................................................. [5-7]
5.2.5 Single phase half wave converter with R - L load ............................................................... [5-10]
5.2.6 Effect of free wheeling diode (Df)........................................................................................ [5-12]
5.2.7 Single phase full converter for R load ................................................................................. [5-14]

7. Table of contentsviii
5.2.8 Single phase fully controlled bridge circuit with (R - L) load................................................ [5-16]
5.2.9 Single phase semi converter ............................................................................................... [5-22]
5.2.9.1 Half controlled bridge rectifier with R load ....................................................... [5-22]
5.2.10 Half controlled bridge rectifier with R - L load ..................................................................... [5-24]
5.2.11 Free wheeling action in semi converter............................................................................... [5-29]
5.2.12 Advantages of half controlled converter over full control converter circuit.......................... [5-29]
5.2.13 Comparison between full converter and semi converter..................................................... [5-29]
5.3 THREE PHASE SYSTEM...............................................................................................[5-35]
5.3.1 Line and phase voltage and currents in three phase delta connection............................... [5-37]
5.3.2 Line and phase voltages and currents in three phases star connection ............................. [5-38]
5.3.3 Power in three phase balanced system .............................................................................. [5-40]
5.3.4 Three phase full converter for resistive (R) load ................................................................. [5-41]
5.3.5 Detailed operation with ‘R’ load for  = 30......................................................................... [5-48]
5.3.6 Three phase semi converter for resistive load .................................................................... [5-48]
5.4 INTRODUCTION TO D.C. – D.C. CONVERTER ............................................................[5-54]
5.5 BASIC CHOPPER CLASSIFICATION ...........................................................................[5-55]
5.6 STEP DOWN CHOPPER ...............................................................................................[5-56]
5.6.1 Principle of operation of step down chopper with R load .................................................... [5-56]
5.6.2 Working principle of step down chopper (bulk converter) with RL load .............................. [5-58]
5.6.3 Step down chopper for RL load (derivation for maximum ripple current)............................ [5-60]
5.6.4 Numericals........................................................................................................................... [5-63]
5.7 STEP UP CHOPPER (BOOST CHOPPER) ...................................................................[5-67]
5.7.1 Numericals........................................................................................................................... [5-69]
5.8 CONTROL STRATEGIES ..............................................................................................[5-71]
5.8.1 Numericals........................................................................................................................... [5-73]
5.9 INTRODUCTION TO D.C. – A.C. CONVERTER (INVERTER).......................................[5-75]
5.9.1 Classification of inverters..................................................................................................... [5-75]
5.10 SINGLE PHASE HALF BRIDGE VOLTAGE SOURCE INVERTERS.............................[5-75]
5.10.1 Operation with resistive R load............................................................................................ [5-75]
5.10.2 Operation with RL Load....................................................................................................... [5-78]
5.11 SINGLE PHASE FULL BRIDGE INVERTER .................................................................[5-82]
5.11.1 Operation with resistive load ............................................................................................... [5-82]
5.11.2 Operation with RL load........................................................................................................ [5-84]
5.12 THREE PHASE BRIDGE INVERTERS ..........................................................................[5-87]
5.12.1 Comparison between the two conduction modes ............................................................. [5-102]
5.13 HARMONIC REDUCTION............................................................................................[5-104]
5.14 LC FILTERS FOR THE CONTROLLED RECTIFIERS.................................................[5-105]
Review Questions........................................................................................................................... [5-106]

8. Table of contents ix
6 APPLICATION OF MOTOR CONTROL................................. [6-1 to 6-59]
6.1 SPEED CONTROL METHOD OF INDUCTION MOTOR..................................................[6-1]
6.2 VOLTAGE SOURCE INVERTER (VSI) CONTROL..........................................................[6-3]
6.2.1 VSI induction motor drives .................................................................................................... [6-3]
6.3 THE CONTROLLED SLIP SYSTEM ................................................................................[6-5]
6.4 SLIP POWER RECOVERY SYSTEM...............................................................................[6-7]
6.4.1 Static Scherbius Drive ............................................................................................................ [6-7]
6.4.2 Static Kramer Drive .............................................................................................................. [6-11]
6.5 VARIABLE FREQUENCY DRIVE (VFD) FUNDAMENTALS..........................................[6-12]
6.5.1 AC motor speed................................................................................................................... [6-12]
6.5.2 Voltage and frequency relationship ..................................................................................... [6-12]
6.5.3 VFD speed torque characteristics ....................................................................................... [6-12]
6.5.4 Variable frequency drive (VFD) output module ................................................................... [6-13]
6.5.5 Inverter principles ................................................................................................................ [6-14]
6.5.6 Output switching sequence ................................................................................................. [6-14]
6.5.7 VFD three-phase waveform ................................................................................................ [6-16]
6.5.8 Pulse width modulation........................................................................................................ [6-16]
6.6 BRAKING OF INDUCTION MOTOR ..............................................................................[6-17]
6.6.1 Regenerative braking .......................................................................................................... [6-17]
6.6.2 Plugging or reverse voltage braking.................................................................................... [6-18]
6.6.3 Dynamic (or rheostatic) braking .......................................................................................... [6-19]
6.7 SINGLE PHASE SCR DRIVE.........................................................................................[6-26]
6.7.1 Single-phase half-wave-converter drives ............................................................................ [6-27]
6.7.2 Single-phase semi converter drives .................................................................................... [6-28]
6.7.3 Single-phase full-converter drives ....................................................................................... [6-29]
6.7.4 Single-phase dual-converter drives..................................................................................... [6-30]
6.8 THREE PHASE SCR DRIVE..........................................................................................[6-31]
6.8.1 Three-phase half-wave-converter drives............................................................................. [6-31]
6.8.2 Three-phase semi converter drives..................................................................................... [6-32]
6.8.3 Three-phase full-converter drives........................................................................................ [6-33]
6.8.4 Three-phase dual-converter drives ..................................................................................... [6-33]
6.9 POWER FACTORS IN SCR MOTOR DRIVES...............................................................[6-34]
6.9.1 Improvement of power factor............................................................................................... [6-34]
6.10 REVERSIBLE SCR DRIVES ..........................................................................................[6-38]
6.10.1 Single fully-controlled rectifier with a reversing switch........................................................ [6-38]
6.10.2 Dual converter ..................................................................................................................... [6-39]
6.10.3 Field current reversal........................................................................................................... [6-40]

9. Table of contentsx
6.11 STARTING AND DYNAMIC BRAKING OF SEPARATELY EXCITED d.c. MOTOR......[6-41]
6.11.1 Transient analysis of starting of separately excited motor with armature control ............... [6-41]
6.11.2 Transient analysis of dynamic braking of separately excited motor.................................... [6-43]
6.12 CLOSED LOOP CONTROL SYSTEM............................................................................[6-44]
6.12.1 Open-loop transfer function................................................................................................. [6-45]
6.12.2 Closed loop transfer function............................................................................................... [6-48]
6.12.3 Phase-locked-loop control................................................................................................... [6-52]
6.12.4 Microcomputer control of d.c. drives ................................................................................... [6-53]
6.13 CHOPPER-CONTROLLED d.c. DRIVES.......................................................................[6-54]
6.14 CHOPPER CONTROL OF SEPARATELY EXCITED DC MOTOR ................................[6-54]
6.14.1 Control of motoring.............................................................................................................. [6-54]
6.14.2 Regenerative braking .......................................................................................................... [6-55]
6.14.3 Motoring and Regenerative Braking.................................................................................... [6-55]
6.14.4 Dynamic Braking ................................................................................................................. [6-57]
6.15 CHOPPER CONTROL OF SERIES MOTOR .................................................................[6-58]
Review Questions............................................................................................................................. [6-58]
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10. DRIVES
AND
CONTROLS
Chinttan N. Dewalia
4/8, Anandnagar, Paud Road, Kothrud, Pune-411038.

11. First Indian Edition, February, 2010
This Book contains information obtained from authentic and highly regarded resources. Reprinted Material is quoted with permission,
and resources are indicated. A wide variety of references are listed. Reasonable efforts have been made to publish reliable data and
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Chinttan N. Dewalia
Diploma in Instrumentation and Control Engineering
(Dr. Babasaheb Ambedkar Technological University, Lonere.)
B.E. Instrumentation Engineering
( Dr. D.Y.Patil college of engineering ,Pimpri,Pune.)
The Indian Edition: Rs. 298.00
Drives and controls
By Chinttan N. Dewalia
© 2010, Chinttan Publications
Published by Chinttan Publications, 4/8, Anandnagar, Paud Road, Kothrud , Pune – 411038., Tel.no.: 8888101055, 9226269333. E-
mail: chinttanpublications@gmail.com
Printed in India

12. xi
Preface
This subject is an introduction to electrical engineering field for Instrumentation engineering students. Application of
electrical machines in the industry and in every field has got the importance day by day. All the fields of engineering as so
much related to each other that going for electrical system of machines introduces drives connected to the machines and
reaches to the vast field of electrical drives which is combination of electronics, namely, power electronics and electrical
machines. Designing the electrical drives for a specific application in the real time environment is really a great challenge.
For this purpose, essentials of Drives and their controls with power electronics is elaborated in the book. This book gives
the detailed discussion of electrical machines as well as drives for controlling them.
For the students of Instrumentation engineering, the simplified contents in for this subject are scarce. As its title
suggests, this is an introductory text to the theory and practice of Electrical drives and controls. It is intended to cover the
needs, as these pertain to the scope of S. E. Instrumentation and control engineering education.
This book is the outcome of notes collected since the graduation. Lot of changes took place from 1997 course to 2008
course. The author has noted the changes and rewritten the articles as per the syllabus.
A considerable effort has been made to make the book clear and easy to read and understand, without sacrificing
details. The theory has been suitably highlighted and reinforced with the help of diagrams and numerical examples.
The book is specially written for second year students of Instrumentation and control engineering. However, it should
prove suitable for other branches of engineering which include electrical machines and the poser electronics as one of
their subjects.
The book has been divided into six chapters as per university syllabus of Industrial data communications. An attempt
has been made to cover whole syllabus as per university’s curriculum.
The book begins with……
Chapter-1 discusses all the details of DC Machines and generators including their mathematical modeling and transfer
functions. Mathematical modeling is very much required in the R & D for designing the systems with
electrical machines.
Chapter-2 describes 3 phase AC Machines, fundamentals of AC and synchronous machines like an alternator.
Chapter-3 explains special machines like single phase Induction motors, synchronous motor, stepper motor, servo motor,
universal motors etc.
Chapter-4 gives the most exhaustive coverage of power devices like SCRs, TRIAC, DIAC, MOSFET, IGBT and UJT used
for AC and DC electrical drives and their control.
Chapter-5 tells about various Controlled rectifiers, chopper controls for AC and DC drives. Finally,
Chapter-6 teaches Industrial AC and DC drive controls, their starting and stopping, voltage frequency drives etc.
INTENDED READERSHIP
The book is specially written for the students of S.E. Instrumentation Engineering university course. It is also seen as
being of value to students of MSc, BSc, Electronics and telecommunications, Electrical engineering, computer
engineering, Electronic Science and Instrumentation Science. It can also be used by senior students and practicing
engineers in the broad field of Control Systems and instrumentation technology.
BACKGROUND KNOWLEDGE ASSUMED
A prerequisite for using this book is basic knowledge of electronics covered in the previous curriculum in the
Instrumentation Engineering course.
A basic knowledge of science and mathematics has been assumed. The science required is basic physical science. Key
elements of science are developed in appropriate chapters. The mathematics required is just the ability to handle the
numbers, integration, summation, interpret graphs and in a few instances, handle simple algebraic equation. Knowledge
of the subject of biology at Xth
and XIIth
class level would be very useful, although not absolutely essential.
- Chinttan N. Dewalia

13. xii
Acknowledgements
Even effort has been made to give credit where it is due for the material contained herein. If inadvertently we have
omitted giving credit, future publications will give due credit to those that are brought to the author’s attention.
I am vastly indebted to many people who have helped and inspired me, in various ways, to start, continue, and
complete this book. I cannot find words to describe the debt I owe to all of my colleagues at various colleges in Pune and
Mumbai University for having created a stimulating atmosphere of academic excellence, the basic element of any long-
lasting endeavor.
My wife Bhaktti and staff of my company typed the original manuscript with great care, artistic taste, skill, and
dedication, unparalleled in my own experience. Assessment of almost all the contents of the book is done by my wife
with great care and we have tried to cover the whole subject as much as possible.
Many thanks to Dr. A. D. Shaligram (Electronic Science Department ,University of Pune) who has been the source of
inspiration for ongoing publishing activity with another new and challenging subject for which I have authored another
book in my eight years of publishing career. As a publisher, whatever I was expecting from the author, I have considered
all those points while writing the book.
Many thanks to all the faculty members & teachers in various colleges in Mumbai & Pune University & those who
supported & encouraged me to publish the various useful & needful books. The books that are bridging the gap of
contents & simplification between reference materials & applied curriculum of engineering course in Mumbai & Pune
University which will further conform to all the curriculums in Indian Universities. This book is the outcome of eight
years of publishing experience and own technical background. The suggestions from all side will be very helpful to the
future reader and students of this subject because the intention is that to have a standard book for this subject. Thanks to
all the students for encouraging me to publish this book.
Unfortunately, sources were not always noted or available; hence, it became impractical to provide an accurate
acknowledgement. Regardless of the source, I wish to express my gratitude to those who may have contributed to this
work, even though anonymously.
- Mr.Chinttan N. Dewalia
D.I.E., B. E. Instrumentation Engg.
(Dr.D.Y.Patil College of Engg., Pune University)
Typesetting, editing and art:
Mrs. Bhaktti C. Dewalia

14. xiii
To my wife Bhaktti

15. xiv
ROADMAP TO THE SYLLABUS
(In accordance with the university revised syllabus for S.E. Instrumentation and control Engineering)
Unit 1: DC Machines : DC generator, working principle, construction feature, types, emf equation, DC motors, motoring
action, torque equation for DC motor, characteristics of DC motor, back emf in DC motor, conventional speed control of
DC motors, Mathematical model of DC motor, Transfer function etc. Starters & applications.
Go to Chapter 1 DC Machines
Unit 2: AC Machines: Asynchronous Machine: Induction motors (3 phase): Concept of rotating magnetic field, working
principle, constructional feature, types, torque equation, torque slip characteristics, efficiency, types of starter,
conventional method of speed control. Ac position control system. Synchronous Machine. (Alternators)Working
principle, construction feature, emf equation, Synchronous speed of Alternators.
Go to Chapter 2 AC Machines
Unit 3: Special purpose Machines: Working principle, construction feature, application and characteristics of Induction
motors (single phase), synchronous motor, stepper motor, servo motor, universal motor.
Go to Chapter 3 Special purpose Machines
Unit 4: Power devices: Construction, principle, Characteristics, Specification, applications of SCR (Gate trigger and
communication circuit, series and parallel connection and its triggering arrangement for series and parallel SCRs), TRIAC,
DIAC, MOSFET, IGBT and UJT.
Go to Chapter 4 Power devices
Unit 5: Controlled rectifier: Invertors and choppers, Single-phase rectifiers and single phase controlled rectifier (Half-
wave and full-wave with resistive, capacitive and inductive loads etc.), 3-phase rectifier and 3 phase-controlled rectifier
(Three phase full wave or six-phase half-wave rectifier, bridge rectifier with resistive load, L-C filter etc.)
Go to Chapter 5 Controlled rectifiers
Unit 6: Application of Motor control: Industrial drive: AC Motor control (speed control method of induction motor
closed loop control, voltage fed inverter control the controlled-slip system slip power recovery system, Voltage frequency
drives (VFD), braking of induction motor) DC Motor control (single-phase SCR drive, Three-phase SCR drive, power
factor in SCR motor devices, reversible SCR drives, starting and dynamic braking of separately excited dc motor, closed
loop control system, chopper controlled dc drives).
Go to Chapter 6 Applications of motor controls