Unit Description and General Aims

The objective of this unit is to familiarise students with the fundamental principles of main types of rotating electrical machines, including motor and generator, operating from DC and AC power supplies, their operation, control techniques, construction/components, and ratings. Additionally, the determination of the efficiency of these machines, common problems, troubleshooting methods, testing of the machines for commissioning and during operation to ascertain their performance, condition monitoring, and essential maintenance aspects, will also be covered. The emphasis will be on AC machines since these types of machines are more widely used in industry.

Learning Outcomes

1. Explain the fundamental principles behind electro-mechanical energy conversion and calculate the relation between motor rated power and torque.
   Bloom's Level 3
2. Describe the principle of operation of DC machines, the function of the commutator, and the different types of DC machines based on field winding connections.
   Bloom's Level 2
3. Explain the theory of 3-phase synchronous machines and the relation between excitation and power factor.
   Bloom's Level 2
4. Explain the fundamental theory of 3 phase and single-phase induction machines, the various types of machines, and their control aspects.
   Bloom's Level 2
5. Discuss the construction of AC machines and the ways of enhancing motor efficiency.
   Bloom's Level 4
6. Describe the procedure for testing AC machines and perform these tests in a simulated environment to calculate motor parameters.
   Bloom's Level 3

Student assessment

Overall Requirements: Students must achieve a result of 50% or above in the exam itself to pass the exam and must pass the exam to be able to pass the unit. An overall final unit score of 50% or above must be achieved to pass the unit once all assessment, including the exam, has been completed.

Prescribed and Recommended Readings

Suggested Textbook

• S. Umans, Fitzgerald and Kingsley's Electric Machinery, 7th Edition. McGraw Hill Education, 2013 - ISBN-13: 978-0073380469

Reference Materials

1. Chapman, S. J., Electric machinery fundamentals fifth edition. Mcgraw-hill, inc.: 2012.
2. Bird J, 2013, Electric Circuit Theory and Technology, Newnes (Elsevier Science), Chapters 21 and 22, ISBN 978-0415662864
3. AC Motors and Protection (MP). IDC Technologies.

Unit Content

Topic 1

Electro-mechanical energy conversion principles

1. Comparison between electrical and magnetic circuit
2. Energy and Geo-energy
3. Induction
4. Forces and torques in magnetic fields and balance equations

Topic 2

DC Machines Part 1 (Generators)

1. Separately excited DC generators
2. Self-excited DC generators
3. Shunt generators
4. Load characteristics of DC generators

Topic 3

DC Machines Part 2 (Motors)

1. Working and principal of DC motors
2. Types of DC motors
3. Speed control of DC motors
4. Faults, Inspection, and maintenance of DC Machines

Topic 4

Synchronous Machines Part 1 (Generators)

1. General aspects and principal of Synchronous Machines
2. Operation of synchronous generators
3. Synchronizing methods (single phase & three phase)
4. Classification of synchronous generators

Topic 5

Synchronous Machines Part 2 (Motors)

1. Operation and construction of synchronous motors
2. Excitation of synchronous motors
3. V-curves and inverted V-curves
4. Characteristics of synchronous motors

Topic 6

Induction Machines – Part 1

1. Principal of single-phase AC machines
2. Equivalent circuit of a single-phase induction machine
3. Explanation of zero starting torque in single-phase induction motors
4. Split winding construction for developing starting torque
5. Universal motors (based on DC series motors)

Topic 7

Induction Machines – Part 2

1. Principal of 3-phase induction motors and generators
2. Equivalent circuit of induction motor and generator
3. Leakage resistance and reactance
4. Starting behavior and the role of back EMF in an induction motor

Topic 8

Control of 3 phase motors and industrial applications – Part 1

1. Torque-speed characteristics of cage and slip ring motors
2. Crawling and cogging problem
3. Impact of voltage reduction on motor torque
4. Direct-on-line starting of a 3-phase induction motor-typical control circuit
5. Reversible motor circuit

Topic 9

Control of 3 phase motors and industrial applications – Part 2

1. Need for assisted starting in weak systems
2. Motor starting methods
3. Motor braking
4. Selection of motor based on torque-speed characteristics

Topic 10

Testing of Motors and Generators

1. DC test
2. No-Load and Blocked rotor test
3. Heat Run test
4. Motor and generator component test

Topic 11

Special Machines

1. Stepper motors
2. Permanent-Magnet DC motors
3. Servo motors
4. Brushless DC motors
5. Brushless Synchronous generators

Topic 12

Unit Review

In the final week students will have an opportunity to review the contents covered so far. Opportunity will be provided for a review of student work and to clarify any outstanding issues. Instructors/facilitators may choose to cover a specialized topic if applicable to that cohort.

Software/Hardware Used

Software

• Software: MATLAB/SIMULINK
• PSCAD
• Version: Student version
• Instructions:  N/A
• Additional resources or files: N/A

Hardware

• N/A

Unit Changes Based on Student Feedback