The full-load copper loss of a transformer is 3200 W. At half-load the copper loss will be – Transformer MCQ#75

The full-load copper loss of a transformer is 3200 W. At half-load the copper loss will be:

1. 6400 W
2. 1600 W
3. 800 W
4. 400 W

Correct answer: 3. 800 W

Explanation: Copper losses = I² R

At half load the current becomes half

Copper losses at half load = (I/2)² R = I²/4 . R = 1/4 ( I² R ) = 3200 / 4 = 800 watts