Question: It is desired to find the equivalent circuit parameters for a single-phase 110V AC transformer. In the short-circuit condition, the transformer can be modelled by a series resistance and inductive reactance. When 5V is applied to the transformer, it draws a current of 20A with a measured input power of 21W. Find the equivalent reactance for the transformer.
So far what I have done is:
I have found the total impedance of the transformer in the short circuit condition, being: Z = R + wL
Then, when 5V is applied, I used ohms law: I=V/R = 5/(R + wL)
to which R + wL = 5/20 = 0.25
However, this is incorrect... The total impedance is not 0.25. I am given some power values, however I am not sure how they can come into play.
I appreciate any help, Thank you.