Hi - Im hoping someone would assist with 3 phase theory

Thread Starter


Joined Jan 2, 2011
I have a STAR connected load comprising of

10L30° in RED phase
30ΩL60° in the BLUE phase 20
20L45° in the YELLOW phase

The line voltage is 230V

I need to determine the current in the NEUTRAL.

So far I have got to....

Ib = Vbn/Z = 120L210° / 30L60°

Ir = Vrn/Z = 120L90° / 10L30°

Iy = Vyn/Z = 120L-30° / 20L45°

I am struggling to identify how to calculate the results for this as all the examples that I have I cannot figure out how they got to the final answer for the neutral current

Sorry for sounding a little dumb just trying to get my head around this...

Thanks alot


Joined Mar 6, 2009
Proceed with calculation of the individual phase currents then algebraically add the three values in their complex form. The resultant complex number will be the Neutral current expressed as a complex value. You would then probably just express that in the complex polar form and take that as your answer.