How can we reduce the copper loss in transformer?

The windings of the transformer are made thick so that the resistances are minimised.Another technique is Vaccum Pressure Impregnation(VPI). In this technique the transformer is kept in vaccum then high pressure varnish is passed so that the smallest of the air gaps are also filled. Hence reducing the copper losses. read more

how to reduce copper losses in a transformer Copper losses are due to the resistance of the copper (or aluminum) windings. To reduce copper losses the transformer would have to be rewound with heavier gage wire. read more

Compare this with full load current for a 1kW transformer on 220VAC - primary current will be \$\frac{1kW}{220V}\$ = 4.55A. To make copper-loss measurements even more exact, a much smaller input primary voltage is used and the secondary winding is shorted. read more