TRANSFORMERS MCQs SET 12
1. Variations in a hysteresis loss in a transformer (Bmax = maximum flux density) ____________
a) Bmax
b) Bmax^1.6
c) Bmax^3.83
d) Bmax/2
a) Bmax
b) Bmax^1.6
c) Bmax^3.83
d) Bmax/2
Answer: b
2. Leakage flux in the transformer depends on _____________________
a) Load current
b) Load current and voltage
c) Load current, voltage and frequency
d) Load current, voltage, frequency and power factor
2. Leakage flux in the transformer depends on _____________________
a) Load current
b) Load current and voltage
c) Load current, voltage and frequency
d) Load current, voltage, frequency and power factor
Answer: a
3. The full-load copper loss of a transformer is 1600 W. At half-load, the copper loss will be _______
a) 6400 W
b) 1600 W
c) 800 W
d) 400 W
3. The full-load copper loss of a transformer is 1600 W. At half-load, the copper loss will be _______
a) 6400 W
b) 1600 W
c) 800 W
d) 400 W
Answer: d
4. Silicon steel used in laminations, because it reduces ________________
a) Hysteresis loss
b) Eddy current losses
c) Copper losses
d) Cannot be determined
4. Silicon steel used in laminations, because it reduces ________________
a) Hysteresis loss
b) Eddy current losses
c) Copper losses
d) Cannot be determined
Answer: a
5. If the supply frequency to the transformer is increased, the iron loss will ___________
a) Not change
b) Decrease
c) Increase
d) Cannot be determined
5. If the supply frequency to the transformer is increased, the iron loss will ___________
a) Not change
b) Decrease
c) Increase
d) Cannot be determined
Answer: c
6. Which of the following can measure iron loss of a transformer?
a) Low power factor wattmeter
b) Unity power factor wattmeter
c) Frequency meter
d) Any type of wattmeter
6. Which of the following can measure iron loss of a transformer?
a) Low power factor wattmeter
b) Unity power factor wattmeter
c) Frequency meter
d) Any type of wattmeter
Answer: a
7. How reduction in core losses and increase in permeability can be obtained simultaneously in a transformer?
a) Core built-up of laminations of cold rolled grain oriented steel
b) Core built-up of laminations of hot rolled sheet
c) Cannot be determined
d) Frequency Meter
7. How reduction in core losses and increase in permeability can be obtained simultaneously in a transformer?
a) Core built-up of laminations of cold rolled grain oriented steel
b) Core built-up of laminations of hot rolled sheet
c) Cannot be determined
d) Frequency Meter
Answer: a
8. Losses which occur in rotating electric machines and do not occur in transformer are ______
a) Friction and windage losses
b) Magnetic losses
c) Hysteresis and eddy current losses
d) Copper losses
8. Losses which occur in rotating electric machines and do not occur in transformer are ______
a) Friction and windage losses
b) Magnetic losses
c) Hysteresis and eddy current losses
d) Copper losses
Answer: a
9. In a given transformer for a given applied voltage, which losses remain constant irrespective of load changes?
a) Hysteresis and eddy current losses
b) Friction and windage losses
c) Copper losses
d) Cannot be determined
9. In a given transformer for a given applied voltage, which losses remain constant irrespective of load changes?
a) Hysteresis and eddy current losses
b) Friction and windage losses
c) Copper losses
d) Cannot be determined
Answer: a
10. Which of the following loss in a transformer is zero even at full load?
a) Core loss
b) Friction loss
c) Eddy current loss
d) Hysteresis loss
10. Which of the following loss in a transformer is zero even at full load?
a) Core loss
b) Friction loss
c) Eddy current loss
d) Hysteresis loss
Answer: b
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