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The core loss of a single phase, 230/115 V, 50 Hz power transformer is measured from 230 V side by feeding the primary (230 V side) from a variable voltage variable frequency source while keeping the secondary open circuited. The core loss is measured to be 1050 W for 230 V, 50 Hz input. The core loss is again measured to be 500 W for 138 V, 30 Hz input. The hysteresis and eddy current losses of the transformer for 230 V, 50 Hz input are respectively,

1. 508 W and 542 W.
2. 468 W and 582 W.
3. 498 W and 552 W.
4. 488 W and 562 W.

Correct answer: 508 W and 542 W.

Solution

The core loss in a transformer consists of hysteresis and eddy current losses, which can be calculated using the Steinmetz equation. By analyzing the losses at different voltages and frequencies, the specific contributions of hysteresis and eddy current losses can be determined, leading to the correct values of 508 W for hysteresis and 542 W for eddy currents.

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