Question

The pole shoes in DC and synchronous machines are laminated to reduce _____________

(a) Resistance losses

(b) Pulsation or pole-face losses

(c) Mechanical losses

(d) None of the mentioned

I have been asked this question during an internship interview.

I would like to ask this question from Losses and Efficiency topic in portion Rating and Loss Dissipation of Electrical Machines

Answer 1

The correct answer is (b) Pulsation or pole-face losses

To explain I would say: The pulsations in flux density wave arising from slot openings cause losses in the field iron, particularly in the pole faces. This loss occurring due to relative motion, between field poles and slotted armature, is referred to as pulsation loss.