Dandel,
That is perfect.
I am using some notes that make no difference in reference to Van, Vbn, and Vcn ANGLES when calculating phase shift in an ordinary delta and a center-tap delta (They do change the Magnitude of the voltage however).
So what I gather from your comments is:
If my orignal secondary was a delta with positve sequence and Vab at 0 degrees, than:
Van = Vab<30,
Vbn = Vbc<30 +240,
Vcn = Vca<30 +120
If I now ground the center-tap on a-b (same xfmr):
Van = Vab/2<0,
Vbn = Vab/2<180,
Vcn = sqrt(Vac^2-Van^2)<90
This makes more sense...
Now, because the secondary has a different phase for the phase voltages...this does not get transformed to the primary right? I mean the line voltages are still the same (in magnitude and phase) and the the xfmr turns ratio is still a real number, so the line voltages on the primary will be the same, and the phase voltages will be offset (lead, I believe?) by 30 degrees.
Thanks for your help... Let me know if I am on the right track.
Also if you know where I can get some good info on tranformer connections and phase shift CALCULATIONS please let me know. My background is controls, so I am pretty "boggled" when trying to determine the effects of one connection to the next.
Regards,
Tulum