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A 1-ϕ transformer has total iron losses of 2500 W at 50 Hz and 400 V input supply voltage. When the applied voltage is 200 V and supply frequency is 25 Hz, the total iron loss is found to be 850 W. Calculate the eddy current loss at 400 V 50 Hz. (Consider V/f ratio as constant)

A 1-ϕ transformer has total iron losses of 2500 W at 50 Hz and 400 V input supply voltage. When the applied voltage is 200 V and supply frequency is 25 Hz, the total iron loss is found to be 850 W. Calculate the eddy current loss at 400 V 50 Hz. (Consider V/f ratio as constant) Correct Answer 1600 W

Concept:

V/f ratio is constant

Wi = Wh + We

Where, Wi = iron losses

Wh = hysteresis loss = Af

We = eddy current loss = Bf2

Calculation:

At 50 Hz, Wi = 2500 W

2500 = A (50) + B (50)2

At 25 Hz, Wi = 850 W

850 = A (25) + B (25)2

Solving the above two equations,

A = 18, B = 0.64

Eddy current loss at 400 V, 50 Hz is

We = Bf2 = 0.64 × 502

We = 1600

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