Question

In a transformer, the core loss is found to be 52 watts at 40 Hz and 90 Watts at 60 Hz; both losses being measured at the same peak flux density. Compute the hysteresis and eddy current losses at 50 Hz.

Answer 1

Core losses in a transformer is the sum of hysteresis loss and eddy current loss.

hysteresis loss is proportional to frequency and eddy current loss is proportional to square of the frequency.

Hence we can write :

core loss = A f + B f²

where A and B are constants.

from the given data we have;

52 = A 40 + B 1600..........eq 1

and

90 = A 60 + B 3600...............eq 2

Solving both the equation we get,

A = 36/40

B = 1/100

Hence putting these values in the equation with frequency 50 hz,

core loss = 36*50/40 + 2500/100

= 45 + 25

= 70 watts

Hence core loss at 50hz is 70 watts.