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Stevenal: Do these GE original test reports include heat release data? Would you upload a typical GE original test report?

prc: We are not going to have these transformers taken out of services and tested for heat release data. I have attached a typical transformer nameplate. Notice that the manufacturer has provided "Impedance Volts 5.90 percent at rated volts at 2000 KVA". The manufacturer either loadbank tested...

prc & edison123: I stand corrected with respect to current versus voltage dependency for flux density and core losses. We do not have original test certificates for these old transformers. Typically we can only get what is on their nameplates. Most manufacturers don't keep this data for their...

prc: As I previously stated "I would of course prefer to use manufacturer's no-load and load-dependent heat-release properties. But they can be difficult to get, especially for old out-of-production transformers." Somehow I must come up with heat release values for these old transformers to...

Forgot to convert Z% to a simple ratio by dividing by 100. kW = kVA * (Z% / 100) / SQRT((X/R)2 + 1)

waross: We use transformer heat release to design its cooling system and want transformer properties at maximum allowable operating temperature.

My understanding is that Z% and X/R are based upon the transformer's total impedance at rated conditions, and thus the Thevenin equivalent of all copper and iron impedances. prc: Are you suggesting that Z% and X/R do not represent the transformer's iron impedances? I would of course prefer to...

Transformer kVA, Z% and X/R are commonly available. Proposing the following equation for transformer heat release: kW = kVA * Z% / SQRT((X/R)2 + 1) Is this equation legitimate? Equation givens: Q = X/R and thus X = Q * R Z2 = X2 + R2 Combining given equations to eliminate X: Z2 = (Q * R)2 +...