Open-Circuit Test Determine core-loss – Rfe , XM Energize the low-voltage side ECE 441
Equivalent Circuit ECE 441
Open-Circuit Test continued Meter readings at rated low-side voltage V = Voc = applied voltage with output open I = Io = magnetization current = I2fe + I2M Poc = core loss = VocIfe >>> Rfe = Voc/Ife XM,LS = Voc/IM ECE 441
Short-Circuit Test Determine equivalent resistance, equivalent leakage reactance, and equivalent impedance of the transformer windings Energize the high-side via an autotransformer or VARIAC. ECE 441
Short-Circuit Test continued Adjust the VARIAC until the high-side current is at the rated value. Measure Psc , Vsc , Isc . ECE 441
Equivalent Circuit ECE 441
Short-Circuit Test continued Zeq,HS = Vsc/Isc Psc = I2scReq,HS >>> Req,HS = Psc/I2sc Zeq,HS = R2eq,HS + X2eq,HS Xeq,HS = Z2eq,HS – R2eq,HS ECE 441