I know this isn't electronics but we're stuck and need help.

We need to derrive an expression for the total power in a three phase STAR and DELTA connected system with a balanced load. the expression must be in terms of line voltages, line currents and power factor.
Thanks daniel.b

 

Sounds like electronics to me.

Three-phase Y and Delta configurations
from the E-book here
http://www.allaboutcircuits.com/vol_2/chpt_10/5.html

That should answer your questions.

 

The power utilized by a balanced three phase system can be calculated as described by the following link:


http://www.ece.msstate.edu/~donohoe/ece3414three_phase_power.pdf