Anna University Chennai 2009-5th Sem B.E Electrical and Electronics Engineering ANNA UNIVERSITY - IESTER S - Question Paper

ANNA UNIVERSITY- COMBATORE
B.E./ B.TECH. DEGREE exam - JUNE 2009.
ELECTRICAL & ELECTONICS ENGG. - 4th SEMESTER
SYNCHRONOUS AND INDUCTION MACHINES
PART-A
ans all ques.. (20*2=40)
1. What are the basic constructional parts of an Alternator.
2. Write the EMF formula of an Alternator.
3. What is known as armature reaction.
4. What are the conditions to be fulfilled for the the parallel operation of alternators.
5. How a synchronous machine is various from an Induction machine.
6. What is known as Hunting in Synchronous machine.
7. What are the applications of synchronous motor.
8. What are the advantages of three phase induction motor over synchronous motor.
9. Give any 2 differences ranging from V & inverted V curves.
10. Define the term slip of an induction motor.
11. What is an induction generator.
12. What are the parameters found through Blocked rotor test.
13. Why high power induction motors should not be started directly.
14. Name various kinds of starters used in three phase induction motor.
15. What are the possible methods available to control the speed of three phase induction motor.
16. What is the significance of cascaded connection of induction motor.
17. What is the necessity knowing double revolving field theory.
18. How a single phase induction motor is made as self starting motor.
19. What are the various kinds of Repulsion motor.
20. What are the features of Universal motor.
PART-B
ans any five. (5*12=60)
1. a) discuss the working principle of operation of an Alternator. (6) b) A three phase 16 pole alternator has star connected winding with 144 slots and 10 conductors per slot. The flux per pole is 0.03Wb. sinusoidally distributed and the speed is 375 rpm. obtain the frequency, phase emf and line emf. presume full pitched coil. (6)
2. a) discuss the working principle of a synchronous motor with neat diagram. (6) b) explain the effect of excitation on armature current and power factor of a synchronous motor. (6)
3. a) discuss the constructional details of squirrel cage rotor of a three phase induction motor with neat diagram. (6) b) The power input to the rotor of 400 volts, 50Hz, six poles, three phase induction motor is 75kw. The rotor electromotive force is observed to make 100 complete alternations per minute. compute 1. slip 2. rotor speed 3. rotor copper loss per phase 4. mechanical power developed. (6)
4. a) discuss the starting mechanism of three phase squirrel cage induction motor using star delta starter with neat diagram. (7) b) Draw the slip-torque characteristics of a three phase induction motor and explain its different regions of operations. (5)
5. a) discuss double revolving field theory of a single phase induction motor. (8) b) Write a brief note on Hysterisis motor. (4)
6. a) How to determine Xd and Xq of a synchronous machine from slip test? discuss with neat diagram. (8) b) explain briefly about synchronous condenser. (4)
7. a) Derive the equivalent circuit model of a three phase induction motor. (8) b) explain in detail the speed control methods of three phase slip ring induction motor supply frequency. (4)
8. a) Draw and discuss the construction of single phase induction motor with neat sketch. (6) b) discuss the working principle of a Stepper motor. (6)

Earning:   Approval pending.