in lecture last week, our instructor gave us an extra credit problem that we had no clue how to solve. i have gotten most of the wye diagram done, and am confused on what to do with the angle at the end.

heres the problem...

A balanced three phase load consisting of 4+j3 ohms per pahse is connected to a 208Y/120V source. Calculate the (1)current per phase, (2)power per phase, and (3)total three phase power for the wye connected load. Repeat for a delta connected load.

for the wye diagram, i got
Ian=41.6A at -36.87 degrees
Ibn=41.6A at -156.87 degrees
Icn=41.6A at 83.13 degrees

Pan=8.65kW at -36.87 degrees
Pbn=8.65kW at 96.87 degrees
Pcn=8.65kW at -23.13 degrees

how do i solve for Ptot? would it be 25.95kW+jQ? and what goes in the place of j and Q?

 

im not even sure if i did the first 2 parts right now

can someone give me an outline on how to do it?

 

I'm a little late getting here.
Your calcs are somewhat off.
If you still want to do this, I'll be glad to help you.
Post again and let me know.........

 

i eventually figured it out after a lot of reading and calculations

thanks

 

Although the site is supposedly "for professional engineers only-no students" you can find some interesting reading here- www.eng-tips.com
The electric power engineering forum gets interesting at times.
Be prepared for some abrupt and downright hostile posts occasionally.

 

i tried posting it there...they didnt like it
also didnt find much helpful info on 3 phase power

 

Sorry you had a bad time at eng-tips.
I can recommend a couple of super good books that cover 3 phase power, motors, transformers and such if you are interested. Or, if you would care to post some specific questions, I'd be glad to try to help. I should warn you however, I'm not an engineer. I'm a journeyman lineman and a protective relay technician. My math is not on the level of a nuclear physicist.

 

thanks for the help/offer, but weve finished going over three phase stuff for now. and im not really liking that topic either.
im actually in ME, but we are required to have some experience with electrical components, so i thought i would take this class.
im hopin to get it back next week with a good grade on it. it was worth up to 100 extra credit quiz points

and it was basically my fault at eng-tips. i didnt read their rules about posting HW help