Question

If induction motor air gap power is 28.63 KW and gross developed power is 18.8 KW, then rotor ohmic loss will be _________ KW.

(a) 9.83

(b) 10.55

(c) 15.54

(d) 4.74

This question was addressed to me in an internship interview.

My doubt stems from Induction Motors topic in division Speed Control of Direct Current Motors & Induction Motors of Electric Drives

Answer 1

Right choice is (a) 9.83

Easiest 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=28.63-18.8=9.83 KW.