Electric Machines

General course objectives:

The course gives the students a knowledge of the theory, properties and operation of various electrical machines. The course develops the students’ abilities to analyze the performance of electrical machines through in-depth knowledge of their principle of operation and to select a machine for a given industry application.

Learning objectives:

A student who has met the objectives of the course will be able to:

• Explain the construction of electrical machines

• Demonstrate understanding of the working principles and characteristics of electrical machines.

• Explain the different techniques for starting and controlling electrical machines

• Analyze equivalent circuits of electrical machines.

• Use equivalent circuit model to calculate the losses in electrical machines

• Simulate electrical machines using Matlab/Simulink

• Perform tests to identify the parameters of electrical machines

• Apply technical knowledge to select electrical machines for industry applications

Content

Introduction to Electrical Machines: electromechanical energy conversion, types of electrical machines, working principle and construction of DC an AC machines, rotating magnetic field, synchronous speed, flux distribution in AC machines, induced voltage and torque in AC machines, full pitch, short pitch, pitch and distribution factors.

DC Machines: Construction and operation of DC Machines, power flow and losses, equivalent circuit of DC machines, types of DC machines, speed control, permanent magnet brushless DC machines.

Induction Machines: Working principle, construction, slip, rotor frequency and voltage, wound rotor induction machine and squirrel cage induction machine, rotor torque, starting torque, running torque, torque relations, equivalent circuit, determination of equivalent circuit parameters, power stages, speed-torque characteristics, blocked rotor test and open circuit test, induction motor starting, speed control, self-exciting and doubly Fed Induction machines, single-phase induction motor: construction, double revolving field theory, slip, equivalent circuit, classifications, starting, ac series motor, capacitor start motor, capacitor start and capacitor run motor, shaded pole motor.

Synchronous machines (both wound field and Permanent Magnet): Construction, poles and frequency, working principle, excitation, emf equation, equivalent circuit, phasor diagrams and voltage regulation, tests, power and torque expressions, salient pole synchronous machine, torque and power expressions, synchronous machine connected to the grid, synchronous generator capability curves, synchronous motor: working principles, starting, equivalent circuit, phasor diagrams, synchronous impedance, effect of different field excitations, phasor diagrams for salient motor, power expression for cylindrical and salient pole motors, v-curves, applications, permanent magnet synchronous machines.

Special machines: Construction and operation of switched reluctance machines and stepper motors.

Course literature

1- A. E. Fitzgerald, Charles Kingsley, Stephen D. Umans, “Electric Machinery”, McGraw Hill, 7th, 2014.

2- Stephen J. Chapman, “Electric Machinery Fundamentals”, McGraw Hill, 5th, 2012.

3- P. C. Sen, “Principles of Electric Machines and Power Electronics”, Wiley, 3rd, 2014. 

Week 1: Introduction

Week 2: Transformers

Week 3: Fundamentals of AC Machines

Week 4: Synchronous machines 1

Week 5: Synchronous machines 2

Week 6: Synchronous machines 3

Week 7: Induction machines 1

Week 8: Induction machines 2

Week 9: Induction machines 3

Week 10: DC Machines

Week 11: Permanent Magnet Brushless DC Machines

Week 12: Switched Reluctance machines