Power Transformer MCQs Part 04

31. Total losses at half load are
a. 52.2 KW
b. 52.2 KVA
c. 26.1 KVA
d. 24 KW

32. What will be the efficiency when the transformed operates at unity power factor and 60% of full load
a. 99%
b. 96.5%
c. 93.3%
d. 91.8%

33. Open circuit test on a transformer yields
a. core losses
b. copper losses
c. sum of core and copper losses
d. leakage of reactance

34. The leakage flux in a transformer depends upon
a. load current
b. load current and voltage
c. load current, voltage and frequency
d. load current, voltage frequency and power factor

35. Which of the following is not a routine test on transformers
a. polarity test
b. radio interference test
c. core insulation voltage test
d. impedance test

36. A transformer will have highest efficiency near
a. 25% of rated load
b. 50% of rated load
c. 75% of rated load
d. 93% of rated load

37. A 1 KVA transformer, at full load will have
a. copper losses a greater than iron losses
b. iron losses greater than copper loses
c. windage losses more than iron losses
d. windage losses less than copper losses

38. The sum of all losses in a 1 KVA transformer at full load will be of the order
a. 10 W
b. 50 W
c. 150 W
d. 250 W

39. In a transformer of peak voltage is fed to primary
a. the iron losses will be less
b. the iron losses will be more
c. the copper losses will be less
d. the windage losses will be more

40. In a transformer the hysteresis losses are 100 K when the input voltage form factor is 2.11 If the input voltage from factor is 1.40 the hysteresis loss will be
a. 140 K
b. 140/111 k
c. 200 K
d. 70 K

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