A 5 kVA transformer has iron loss of 200 W and full load copper loss of 350 W. The maximum efficiency of the transformer would occur when the total loss is _________.

Question

Question

This question was previously asked in

SSC JE Electrical 15 Nov 2022 Shift 2 Official Paper

Answer 1

Concept

The total losses in the transformer are:

PT = Iron loss + Copper loss

At maximum efficiency:

Iron loss = Copper loss

Thus, PT = 2 × Iron loss

P_c = (x)²P_cufl

\(x=\sqrt{P_c\over P_{cufl}}\)

where, x = Fraction of loading

Calculation

Given, Iron loss = 200 W

At maximum efficiency:

PT = 2 × 200

PT = 400 W