Part- A

1. Write down the principle of energy conversion.

2. Give an example for single and double excited system.

3. Define field energy and co-energy?

4. Draw an energy flow diagram of an electromechanical energy conversion device when it acts as a motor.

5. Write the Energy balance equation of a machine.

6. Draw the i-λ characteristic of a non-linear magnetic circuit.

7. List three types of electromechanical energy conversion devices?

8. Write the relation between electrical and mechanical degree.

9. Define winding factor.

10. What is full pitch and short pitch winding?

11. What are the advantages of the stator coils are short pitched? Why fractional pitch winding is preferred over full pitch winding?

12. What is an Exciter and its function?

13. State the assumptions for peak value of the MMF wave.

14. Describe rotating magnetic field.

15. State the torque equation for round rotor machine.

Part- B

16. Two coupled coils have self and mutual inductance of L11 = 2+(1/2x), L22= 1+(1/2x),
L21 = 1/2x over a certain range of linear displacement x. The first coil is excited by a Constant current of 20 A and the second by a constant current of -10 A. Find a) Mechanical work done if x ranges from 0.5 to 1m. (b) Energy supplied by each electrical source.

17. (a) Derive the expression for torque in a singly excited system.

(b) Explain the i-λ characteristic of a magnetic system. Also derive the expression for Co-energy density assumed the i-λ relationship of the magnetic circuit is linear.

18. Derive the torque equation of a round rotor machine. Also clearly state what are the assumptions made?

19. A 3 phase, 50KW,4 pole,50Hz induction motor has a winding designed for delta connection. The winding has 24 conductors per slot arranged in 60 slots. The RMS value of the line current is 48 A. Find the fundamental of mmf wave of phase winding when the current is passing through its maximum value. What is the speed and peak value of the resultant mmf/pole.