Question

Calculate the active power in a 168.12 H inductor.

(a) 65 W

(b) 0 W

(c) 68 W

(d) 64 W

I have been asked this question in semester exam.

This is a very interesting question from Induction Motors topic in division Speed Control of Direct Current Motors & Induction Motors of Electric Drives

Answer 1

Correct answer is (b) 0 W

Best explanation: The inductor is a linear element. It only absorbs reactive power and stores it in the form of oscillating energy. The voltage and current are 90° in phase in case of the inductor so the angle between V & I is 90°. P = VIcos90° = 0 W.