Irwin 11.27 3 Phase Tutorial Video

[Dodgeviper1017]

In a balanced three phase wye-delta system the source has an abc phase sequence and Van = 120 angle 40 Vrms. The line and load impedance's are 0.4+j0.4 and 24+j18 respectively. Find the Delta currents in the load? Link to the video: https://www.youtube.com/results?search_query=Irwin+11.27

So I tried this a different way first I converted given phase voltage to line which gives me 208 angle 70, then I used a votage divider (24+j18)/(24.5+j18.4) to find VAB and then divided by 24+j18. This gives me 6.783 angle 33 which is the same answer he gets essentially. The other way would be to convert Delta into wye and work like that. I guess I just wanted to post this so others could see this problem as it stumped me at first because I didnt see to convert Delta to wye at first and tried to do a convoluted KVl for some unknown reason.

 

[Dodgeviper1017]

The more I look at this the less I understand why what I did worked because I didnt take into account the other line impedance in series on the bottom. Any help is greatly appreciated?

 

[Dodgeviper1017]

Well even if I include the last bit in series I still get really close 6.64 angle 33. So should I take into account all impedance in series when doing voltage divider method or not? I find this answer to be with 2% of the actual, so i would probably get it right on the test anyway, but I am curious.