Can someone help me with below 2 questions?

1. A 208 V three phase system has a balanced load consisting of three 15 Ohm resistances. What power is dissipated if the connection is wye?

2. A 208 V three phase system has a balanced load consisting of three 15 Ohm resistances. What power is dissipated if the connection is Delta?

Thanks,

 

These are relatively simple problems.

In the balanced 3-phase systems of either Q1 or Q2 the individual phase resistor powers are identical. Find the the power in one resistor and multiply by three to get the total power. The only difference in the wye or delta cases is the actual voltage across the 15Ω resistors is different. So there will be more power in one case than in the other.

It's up to you to apply your knowledge and show an attempt at working a solution.

 

Is it true that the three-phase power formulas are the same regardless of the connected loads (delta or wye)?

 

Is it true that the three-phase power formulas are the same regardless of the connected loads (delta or wye)?

What do you mean?

If you read my post it specifically says the powers will be different depending on whether the 3 loads are connected in wye or delta. I said that in a balanced system the individual phase powers are the same.

 

Hello,

Take also a look at this page from the Ebook:
http://www.allaboutcircuits.com/vol_2/chpt_10/5.html

Greetings,
Bertus