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For a power transformer operating at full load it draws voltage and current equal to 200 V and 100 A respectively at 0.8 pf. Iron and copper losses are equal to 120 kW and 300kW. What is efficiency?

For a power transformer operating at full load it draws voltage and current equal to 200 V and 100 A respectively at 0.8 pf. Iron and copper losses are equal to 120 kW and 300kW. What is efficiency? Correct Answer 97.44%

Power output= VI cosθ= 200*100*0.8 = 16000 W (Independent of lag and lead). While total losses are equal to iron loss+ k2*copper losses =120+ 300= 420 W. Efficiency is equal to 1- 420/(16000+420)= 97.44%.

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