Course Title
Electrical Machine – I
Course Code
EL321
Lecture
: 03
Practical
: 01
Tutorial
: 00
Total
: 04
Course Credit
Course Learning Objective
At the end of this course students will be able to:
 Understand the basics of Electromagnetics and concept of rotating machines.
 Analyze construction, working and characteristics of DC Machines.
 Interpret construction, working, characteristics of transformers.
 Perform the testing of DC machines and transformers.
Detailed Syllabus
Sr.
No.
1
2
3
Hours
Allotted
Name of chapter & details
Section – I
Basic Concepts of Rotating Machines
Introduction to magnetic circuits, Magnetically induced e.m.f and force, AC
operation of magnetic circuits, Hysteresis and Eddy current losses, Basics of
electromechanical energy conversion.
DC Generator
Construction feature of DC Machine, Principle of operation of DC Generator,
EMF equation, Types of excitation, Armature reaction, Commutation, No load
and load characteristics of DC generators, Voltage regulation, Applications.
DC Motor
Principle of operation of DC motors, Types of DC motors, Back emf, Speed
and torque equation, Operating characteristics of different DC motors, Starting
of DC motors: 2 point starter, 3 point starter, 4 point starter, speed control,
Losses and efficiency, Applications.
Total hours
04
07
10
21
Section – II
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4
Transformers
Operating principle, Constructional features of single phase and three phase
transformer, EMF equation, Transformer on no load and load, Vector diagram
and equivalent circuit, Voltage regulation, Three phase transformer
connections, three phase to two phase transformations, Effect of harmonics,
Magnetic inrush phenomena, Auto transformer.
5
Testing of DC machine and Transforms
Losses and efficiency, Condition for maximum efficiency, Testing of DC
machines: Brake test, Swinburne’s test, Retardation test, Hopkinson’s test-,
Testing of transformer: polarity test, load test, open circuit and short circuit test,
Sumpner’s test, All day efficiency.
Total hours
14
07
21
Instructional Method and Pedagogy


Lectures will be conducted with the aid of multi-media projector, black board, OHP etc.
Assignments based on course content will be given to the students at the end of each
unit/topic and will be evaluated at regular interval.
 Surprise tests/Quizzes/Seminar/Tutorials will be conducted.
 The course includes a laboratory, where students have an opportunity to build an appreciation
for the concepts being taught in lectures.
 Minimum ten experiments shall be there in the laboratory related to course contents.
Reference Books
1. J B Gupta, “Theory & Performance of Electrical Machines”, S. K. Katariya & Sons
Publication.
2. Theodore Wildi, “Electrical Machines, Drives and Power System”, Pearson Publication.
3. K. R. Siddhapura, D B Raval, “A Textbook of Electrical Machines”, Vikas Publishing
House Pvt Ltd.
4. I.J Nagrath and D.P. Kothari,”Electric Machines”, Tata McGraw-Hill Education.
5. Ashfaq Husain, “Electric Machines”, Dhanpat Rai & Co.
6. B L Theraja , “Electrical Technology”, Vol II, S Chand Publication.
Additional Resources
http://nptel.ac.in/courses/108105017/
http://nptel.ac.in/courses/108106071/
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List of Experiments
Subject Code :
Subject Name : Electrical Machine – I
Sr.
No
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Aim of experiment
To Discuss the construction and working principle of Single phase Transformer.
To Discuss the construction and working principle of DC Machines.
To Examine voltage ratio test and polarity test of single phase transformer.
To Demonstrate open circuit (O.C.) and short circuit (S.C.) test on single phase
transformer & calculate its equivalent circuit parameters.
To Analyze Magnetization characteristic (O.C.C.) of a D.C. Generator.
To Analyze internal & external characteristic of D.C. shunt generator.
To Predict efficiency & voltage regulation of single phase transformer by direct loading
test.
To Demonstrate Swinburne’s test on D.C. Shunt motor.
To Demonstrate (Back to Back) test on single phase transformer
To Demonstrate load test on D.C. series motor and analyze its characteristic.
To Create two phase supply from existing 3 phase supply using T-connection of
transformer
To Create two phase supply from existing 3 phase supply using scott connection.
To Demonstrate the different types of starter used in dc machine.
To Examine the parallel operation of single phase transformer
To Analyze the speed of DC series generator using armature resistance control method
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