Question

In three phase system at any given instant, the algebraic sum of three voltages must be?

(a) 0

(b) 1

(c) 2

(d) 3

The question was posed to me in an international level competition.

I want to ask this question from Polyphase System in chapter Polyphase Circuits of Network Theory

Answer 1

Right answer is (a) 0

To elaborate: For three phase alternator the three voltages are of same magnitude and frequency. In three phase system at any given instant, the algebraic sum of three voltages must be zero. Algebraic sum of three voltages = 0.