Engineering

1. EET 3257: Electrical Machines I
Contact Hours: 45
Course Purpose
To introduce students to fundamentals of electrical machines and their applications in drive systems.
Expected Learning Outcomes
Upon completion of this course, a student should be able to:
1. Describe the principles of magnetism;
2. Describe the principles of electromagnetic induction;
3. Understand theory of electromechanical energy conversion;
4. Understand concepts of fundamental torque equation and rotating and oscillating fields;
5. Understands the concept of the equivalent electrical machine circuit;
6. Formulate relevant equivalent circuits;
7. Describe the construction and principle of operation of dc machines;
8. Derive dc motor and generator characteristics in series, shunt and compound modes;
9. Analyse speed control of dc motor;
10. Derive generated voltage of dc generator;
11. Calculate required power, efficiency, losses in dc machines;
Course Content
Magnetics: Magnetic materials, hysteresis loop, saturation and voltage regulation, magnetic terms and
units, magnetic flux and m.m.f. relationship, magnetic circuits, Kirchhoff's laws applied to magnetic
circuits, stored energy, self and mutual inductance, induced e.m.f. and stored energy. Principles of
Electromagnetic energy conversion: Fundamentals of torque production, energy balance equation of an
electromechanical system; force and torque as rates of change of stored energy.
DC Machines: construction, principle of operation, e.m.f. and torque equations, armature reaction and
commutation, calculation of de-magnetising and cross magnetising ampere turns, DC. Motors:
construction, principle of operation, e.m.f. and torque equations, significance of back e.m.f., machine
characteristics, type of d.c motor (series, shunt and compound) d.c. motor starters, control of motor
speed, losses and efficiency.
D.C Generators: Construction, Characteristics, Operation and application, types (shunt, series and
compound)
Course Assessment
Type Weighting (%)
Examination 60
Continuous Assessment 10
Practical 25
Assignment 5
Total 100
Recommended books
1. B.L. Theraja, Electrical Technology, Vol. I
2. Steven J. Chapman, Electric Machinery Fundamentals, McGraw Hill, ISBN 0-07-011950-3.
3. S. K Bhattacharya, Electrical Machines, McGraw Hill,
4. A.E. Fitzgerald, Charles Kingsley, Jr. and Stephen D. Umans, Electric Machinery, Sixth Edition,
2003, McGraw-Hill, ISBN 0073660094