In a three-phase, symmetrical, star-connected generator, phase sequence ABC, the phase voltage is 𝑉an=100∠40° 𝑉.

Question

The phase voltage 𝑉cn is:

(A) 100∠-80° 𝑉.

(B) 100∠160° 𝑉.

(C) 100∠120° 𝑉.

(D) 100∠-120° 𝑉.

(E) 100∠0° 𝑉.

Answer 1

This is a balanced three-phase circuit problem.

A phase sequence of ABC is also known as a positive sequence.

REF=40^o

V_an=V_rms ∠REF

V_bn=V_rms ∠REF-120^o

V_cn=V_rms ∠REF+120^o

V_cn=100∠160^o V

The Answer is B or V_cn=100∠160^o V