A 50 Hz transformer having equal hysteresis and eddy current losses at rated excitation is operated at 45 Hz at 90% of its rated voltage. Compared to rated operating point, the core losses under this condition:

A 3-phase squirrel cage induction motor has a full load efficiency of 0.8 and a maximum efficiency of 0.9. It is operated at a slip of 0.6 by applying a reduced voltage. The efficiency of the motor at this operating point is:

The efficiency of a 100 kVA transform is 0.98 at full as well as at half load. For this transformer at full load the copper loss.

The magnetizing current in a transformer is rich in