A 500 kVA, 3-phase transformer has iron losses of 300 W and full load copper losses of 600 W. The percentage

A 500 kVA, 3-phase transformer has iron losses of 300 W and full load copper losses of 600 W. The percentage load at which the transformer is expected to have maximum efficiency is 

(A) 50.0% (B) 70.7% (C) 141.4% (D) 200.0%
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Answer :

A 500 kVA, 3-phase transformer has iron losses of 300 W and full load copper losses of 600 W. The percentage load at which the transformer is expected to have maximum efficiency is 70.7%

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