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Open-Circuit Test. Determine core-loss – R fe , X M Energize the low-voltage side. Equivalent Circuit. Open-Circuit Test continued. Meter readings at rated low-side voltage V = V oc = applied voltage with output open I = I o = magnetization current = I 2 fe + I 2 M
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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