1. The problem statement, all variables and given/known data A single phase 500V/250V transformer that supplies a rated load current of 10 A with a power factor of 0.8 lagging. At no load, the supplied current is 0.25 A with a power factor of 0.10 lagging. I am supposed to find the full-load primary current and express it in polar form. Winding impedance voltage drop can be neglected. 2. Relevant equations I=Io + I2' I2'=(N2/N1)*I2 V2/V1=N2/N1 3. The attempt at a solution Full Load 500V/250V=N1/N2 I think that rated load current is = to I2 therefore, I2'=(250/500)*10 A I2'=5 A No Load Io=0.25 A using the equation I=Io + I2' I= 5 A + 0.25 A I=5.25 A Does everything look ok so far? At this point I'm not sure how to find the angle of I.