Question

What is the relation of hysteresis loss and weight of iron parts with respect to increase of number of poles?

(a) decrease in hysteresis loss, increase in weight

(b) decrease in hysteresis loss, decrease in weight

(c) increase in hysteresis loss, increase in weight

(d) increase in hysteresis loss, decrease in weight

This question was posed to me in an interview for job.

I would like to ask this question from Selection of Number of Poles in section Thermal Design Aspects of Electrical Machines & D.C of Design of Electrical Machines

Answer 1

Correct choice is (b) decrease in hysteresis loss, decrease in weight

To explain I would say: With larger number of poles, the area of cross section can be reduced, henceforth decreasing the hysteresis loss. Also by increasing pole number, weight of iron parts is reduced.