Question

In a delta connected system, the voltage across the terminals R and Y is 400∠0⁰. Calculate the line voltage VRY. Assume RRY phase sequence.

(a) 400∠0⁰

(b) 400∠120⁰

(c) 400∠-120⁰

(d) 400∠240⁰

The question was posed to me in an interview.

Asked question is from Voltage, Current and Power in a Delta Connected System topic in section Polyphase Circuits of Network Theory

Answer 1

Right answer is (a) 400∠0⁰

For explanation I would say: In a balanced delta-connected system we know |VRY| = |VPh|, and it is displaced by 120⁰, therefore the line voltage VRY is VRY = 400∠0⁰V.