A set of open circuit test and short circuit test have been performed on a transformer. A supply voltage of 480 V is applied to the primary side of the transformer and the following data is obtained for the open circuit test.
Poc 720 W
Voc 240 V
Io 9.7 A
Then, the following set of data is taken for a short circuit test.
Psc 750 W
Vsc 37.2 V
Isc 51.9 A
Later, the high side of the transformer is connected to a multi-meter with the low side left open. The meter registers a reading of 0.11 ohm. Afterwards, the multi-meter is connected to the low side with the high side left open. The meter registers a reading of 0.029 ohm.
It is generally assumed that for this 2:1 transformer that the reactance at both sides contributes equally to the equivalent reactance of the transformer.
The resistance readings collected after the open and short circuit tests are the resistance reading when the transformer is operating with DC. Supposedly, the resistance collected should be the same as the leakage resistance, distributed with the same ratio on the primary and secondary side of the transformer. However, this is not always true. Due to certain unknown factors, the leakage resistance deduced from short circuit test is higher than the value obtained with DC source.
Find out the following:
1. The leakage resistance on the primary and secondary sides
2. The leakage reactance on the primary and secondary sides
3. Is the leakage resistance higher than the value obtained with DC source? Why