Question

What must be done in order to take additional iron losses into account in dc machines?

(a) iron loss obtained from iron loss curve is multiplied by 1.2-1.4

(b) iron loss obtained from iron loss curve is multiplied by 1.4-1.6

(c) iron loss obtained from iron loss curve is multiplied by 1.3-1.5

(d) iron loss obtained from iron loss curve is multiplied by 1.15-1.25

I had been asked this question during an online interview.

Enquiry is from Determination of Iron Losses & Slot Leakage topic in chapter Principles of Magnetic Circuit Design of Design of Electrical Machines

Answer 1

The correct answer is (b) iron loss obtained from iron loss curve is multiplied by 1.4-1.6

To explain I would say: In order to take additional losses into account the iron loss obtained from the iron loss curves is multiplied into 1.4-1.6 in dc machines and synchronous machines. The iron loss obtained from the iron loss curves is multiplied into 1.2-1.4 in induction motors.