Question

In an induction motor, which of the following is correct?

(a) Stator core loss < rotor core loss

(b) Stator core loss = rotor core loss

(c) Stator core loss > rotor core loss

(d) Any of the mentioned

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

This is a very interesting question from Losses and Efficiency topic in section Rating and Loss Dissipation of Electrical Machines

Answer 1

Correct option is (c) Stator core loss > rotor core loss

To explain I would say: The rotor core loss is almost negligible because of reduced frequency of the flux reversals (equal to slip frequency, sf) in the rotor, and Pe∝f^2 and Ph∝f. (Pe = eddy current losses,  Ph = hysteresis losses).