41) The copper loss of the transformer during the maximum efficiency is 1000 watts, what will be the Iron loss ?

42) The efficiency of a transformer is at a maximum value, when the

43) Generally a transformer has the efficiency of

44) Results of a transformer with a rating of 15 kVA, 1100V/ 220V, 50Hz are obtained, while testing. Short circuit test power input = 510 watts. Open circuit test power input = 252 watts. What is the efficiency of the transformer at full load, 0.8 p.f.?

45) What is the maximum load upto which an open delta transformer can safely maintain supply to load ?