In a transformer load test (Resistive and at a unity power factor), what should be the...
In a transformer load test (Resistive and at a unity power factor), what should be the expected voltage regulation and primary power factor?
Homework Answers
In case of resistive load and at a unity power factor, the load current is in phase with secondary voltage.
Therefore, voltage regulation =
(V0(NL) - V0(FL) )/V0(FL)
V0(NL) = Transformer no load output voltage
V0(FL) = Transformer full load output voltage
The no load output voltage is bigger than its full load output voltage, so the above equation is positive.
When the transformer has resistive load and at a unity power factor, the primary power factor = 0.95 lag.
Power factor is defined as the ratio of real power to apparent power. The power factor of the transformer is load dependent.
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