Question

If the load impedance is Z∠Ø, the expression obtained for current (IY) is?

(a) (V/Z)∠-120+Ø

(b) (V/Z)∠120-Ø

(c) (V/Z)∠120+Ø

(d) (V/Z)∠-120-Ø

I have been asked this question during an online exam.

My question is from Three-Phase Balanced Circuits in portion Polyphase Circuits of Network Theory

Answer 1

Correct choice is (d) (V/Z)∠-120-Ø

Explanation: As the load impedance is Z∠Ø, the current flows in the three load impedances and the current flowing in the Y impedance is IY = VYB∠120⁰/Z∠Ø = (V/Z)∠-120-Ø.