SPECIAL ELECTRICAL MACHINES May/June 2007 Question paper seventh semester EEE

Seventh semester
(Regulation 2004)
Electrical and Electronics Engineering
(Common to B.E.(Part Time) Sixth Semester regulation 2005)
Time : Three Hours Maximum: 100 marks
Answer all questions
PART A –(10x2=20)

1. What is the main advantage of synchronous reluctance motor?
2. List the application of synchronous reluctance motor.
3. Define the term step angle.
4. What is meant by detent torque?
5. What is the significance of closed loop control in switched reluctance motor?
6. List out the advantages of switched reluctance motor.
7. What are the types of materials used in PMDC motors?
8. State some important applications of PMDC motor?
9. How a permanent magnet synchronous motor is stated?
10. What are the advantages of permanent magnet synchronous motor?

PART B – (5x16 = 80 marks)

11.(a) Describe the construction working and uses of a reluctance motor. (16)
(b) Draw and explain a typical torque speed characteristics of a reluctance motor. Compare a reluctance motor with an equivalent induction motor. (16)

12. (a) describe the operation of a variable reluctance type stepper motor. What is meant by micro stepping also explain? (16)
(b) (i) Explain the working of a hybrid stepper motor. (8)
(ii) Draw and explain the torque pulse rate characteristics of stepper motor. (8)

13.(a) With neat diagram, explain the construction and working of switched reluctance motor. (16)
(b) (i) With neat diagram, explain the importance of closed loop control in SR motor. (10)
(ii) Compare SR motor with VR stepper motor. (6)

14.(a) Describe the construction of a permanent magnet dc motor. What are the advantages and disadvantages of PMDC motors compared with conventional shunt dc motors? (16)
(b) (i) Explain the speed torque characteristics of PMDC motor. (8)
(ii) Write a note on power controllers used in PMDC motor. (8)
15. (a) Explain the construction and performance of permanent magnet synchronous motor with neat diagram. (16)
(b) Clearly explain the microprocessor based control of PMSM. (16)
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