Question

If induction motor air gap power is 1.8 KW and gross developed power is .1 KW, then rotor ohmic loss will be _________ KW.

(a) 1.7

(b) 2.7

(c) 3.7

(d) 4.7

I have been asked this question during an online interview.

This intriguing question comes from Induction Motors Speed Control in portion Speed Control of Direct Current Motors & Induction Motors of Electric Drives

Answer 1

The correct answer is (a) 1.7

The explanation: Rotor ohmic losses are due to the resistance of armature windings. Net input power to the rotor is equal to the sum of rotor ohmic losses and mechanically developed power. Rotor ohmic losses=Air gap power-Mechanical developed power = 1.8-.1=1.7 KW.