AIMS:

This course builds on the Electrical Power Course given in Part 1B. The course recognises that electrical motor drives in applications of all kinds are required to perform at high efficiency, controllability and reliability. The course will be delivered with emphasis on design and applications. It will start by looking at the basic principles of motor design and then it will look at three major areas in which electric motors are used. The first is general household use and is typified by single phase motors. Secondly the course will examine three phase motors which are heavily utilised in industry for applications such as trains, pumps and conveyor belts. The final area will look at high precision machines such as salient pole motors which are used at the small end of mechatronics and pernament magnet motors which are high performance machines also of use in mechatronics. In the final part of the course the ideas explored will be put to further use by looking at the overall design of mechatronic devices such as robots.

SYLLABUS

1. Motor Design (4 lectures)

• Basic ac winding design, specific magnetic and electric loadings, air gap volume, magnetic circuit design, saturation effects. Thermal considerations

2. All-Electric vehicles (1.5 lectures)

• There are two main areas where the all-electric vehicle is being considered. The first is in aircraft where considerable advantage can be gained from the removal of mechanical systems which require bulky and expensive cooling systems and the replacement of these by electric motors and generators. The second is the electric car, where the goal is to remove pollution from the streets of busy towns. These lectures will explore the problems and the practicalities of these systems.

3. Single-phase motors ( 1.5 lectures)

• Single-phase induction motors - split-phase, capacitor-start, permanent split capacitor, shaded-pole variants, ac commutator motors.

4. Three-phase motors ( 2 lectures )

• Voltage source and current source, variable frequency three-phase induction motor drives. Open and closed-loop control schemes for induction motor drives. Analysis of the drive in the steady state.

5. Reluctance machines ( 2 lectures )

• Salient-pole synchronous machines, stepper motor single-step and multi-step operation, switched-reluctance motors - principles of operation, behaviour, applications. Variable frequency operation and principal control strategies.

6. Permanent magnet machines (2 lectures )

• Brushed and brushless motors, magnet materials (power/weight, cost, type), general principles of operation.

6. Mechatronics design ( 3 lectures)

• Multiplexing of mutiple drive machines. Such as in robotics or rolling mills

OBJECTIVES

On completion of the module, student should be able to:

• Understand the basic principles of operation;
• Be able to apply simple motor design rules;
• Be able to specify diffferent motors for different applications;
• Understand the design contstriants on multiple motor machines;
• Appreciate magnetic and thermal constraints;
• Be aware of different magnet materials and suitability for motor operation;

REFERENCES

Please see the Booklist for Part IIA Courses for references for this module.