unbalanced delta

[rrzzan]

Hi Guys,

I have an unbalanced delta load. Phase AB 7.7Amp Phase BC 7.7 Amp Phase CA 7 Amp.
The power is also supplied form a delta source.

I have also calculated the vector IAB = 7.08+3i, IBC = 7.08+3i and ICA = 6.44+2.73i
Also IA = - (0.644+ 0.27i)
IB = 0+0i
IC = 0.644-+0.27i
What would be the magnitude of IA, IB, IC ?
(If it was 7.7 Amps in all the three phases the magnitude of current would have been 1.732* 7.7 =13.34Amp)

Thanks for your help.
R

 

[jghrist]

I think you must be measuring your IAB, IBC, and ICA angles with respect to the associated Ø-Ø voltage angle instead of to a common reference angle. If all three Ø-Ø currents were identical in magnitude and angle, there would be no line current. You would have zero-sequence currents circulating in the delta loads.

I suspect that you need to rotate IBC by 120° and ICA by 240° to get them to a common reference.

 

[alehman]

The magnitude is sqrt(Ireal^2 + Iimag^2)

How did you determine IA, IB and IC?

Alan
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"It’s always fun to do the impossible." - Walt Disney