Electrical Machines Multiple Choice Questions and Answers

21. The harmonics in rotating machines are generated due to

1. Non-sinusoidal field form
2. Slotting of the stator core
3. Both (A) and (B) above
4. None of the above

22. The effect of harmonics in rotating machines can be minimized by

1. Use of longer air gap
2. Skewing the poles
3. Use of distributed winding
4. all of the above

23. In dc machines the number of poles is generally decided by

1. Frequency of flux reversals
2. Weight of iron parts
3. Weight of copper
4. all of the above

24. In dc machines by increasing the number of poles, all of the following reduce except:

1. Weight of copper
2. Weight of iron parts
3. Frequency of flux reversals
4. Overall size of the machine