Page 583 - Basic Electrical Engineering

Solution:

Power consumed on no-load test can be taken approximately equal to the
core loss, and power loss on the short-circuit test when the rated current

flows through the windings can be taken as equal to full-load copper loss.

I = 5 A; and full-load current at the high-voltage side
sc

Thus, we see that the short-circuit test was conducted under the full-load
condition.

Therefore,

and

Efficiency

Full load copper loss