three phase systems

Thread Starter


Joined Jan 24, 2006
Hi to all the experts out there,
I'm completely stuck with 2 homework questions if anyone can help you would be my life saver. Its basically just starting off and being 100% sure if I'm correct or not at the beginning. As you well know if you can answer these types of questions correctly if incorrect all the answers that follow on are also incorrect.

1) A symetrical 3 phase, 400V system supplies a balanced delta connected load
the black to brown branch 20 /_40 degrees A
Line Current
The total power

2) A three phase, four wire, 440V system is loaded as follows:
.. an inductive motor load of 350KW at 0.707 lagging
.. Resistive loads of 150KW,250KW and 400KW connected beteween the brown, black and grey lines to neutral
sequence is Br / BL / GR
Line Current
The Current in the Neutral
The Overall Power Factor

If nothing else can anyone just push me in the right direction ( line current is the problem ) and my conversion from polar .


Joined Jan 23, 2006

For future reference, pick up Schaum's Outline of Electric Circuits. It is a great reference for help when solving homework problems.

Please include the progress you have made thus far in each problem.

Also in the first problem, please refresh my memory by defining the 20/_40 Degrees A.

Thank you