# Got a question on 3 phase power

Discussion in 'Homework Help' started by purdub, Nov 14, 2006.

1. ### purdub Thread Starter New Member

Nov 14, 2006
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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?

2. ### purdub Thread Starter New Member

Nov 14, 2006
5
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im not even sure if i did the first 2 parts right now

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

3. ### subtech Senior Member

Nov 21, 2006
123
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I'm a little late getting here.
Post again and let me know.........

4. ### purdub Thread Starter New Member

Nov 14, 2006
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i eventually figured it out after a lot of reading and calculations

thanks

5. ### subtech Senior Member

Nov 21, 2006
123
5
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.

6. ### purdub Thread Starter New Member

Nov 14, 2006
5
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i tried posting it there...they didnt like it
also didnt find much helpful info on 3 phase power

Nov 21, 2006
123
5