Question

The full load copper-loss and iron-loss of a transformer are 6400 W and 5000 W respectively. The copper-loss and iron-loss at half full-load will be:

• A. 3200 W and 2500 W
• B. 3200 W and 5200 W
• C. 1600 W and 1250 W
• D. 1600 W and 5000 W

Hint:

Copper loss varies with the square of the load, while iron loss remains constant at all loads.

Answer 1

The Correct Option is D

For a transformer:
- The copper loss is proportional to the square of the load. At half-load, the copper loss will be reduced by a factor of \( (1/2)^2 = 1/4 \).
- The iron loss (core loss) remains constant regardless of the load.
Given:
- Full-load copper loss = 6400 W, so at half-load the copper loss will be:
\[ \text{Copper loss at half-load} = \frac{6400}{4} = 1600 \, \text{W} \] - Full-load iron loss = 5000 W, and since it is constant, the iron loss at half-load remains:
\[ \text{Iron loss at half-load} = 5000 \, \text{W} \] Thus, the copper-loss at half full-load is 1600 W and the iron-loss remains 5000 W, which corresponds to option (4).