TRANSFORMERS MCQs SET 11

TRANSFORMERS MCQs SET 11

1. Which of the following is not considered in the standard voltage scale for power supply in India?
a) 11kV
b) 33kV
c) 66kV
d) 122kV
 

Answer: d

2. The maximum load that a power transformer can carry is limited because of its ___________
a) temperature rise
b) dielectric strength of oil
c) voltage ratio
d) copper loss
 

Answer: c

3. The voltage transformation ratio of a transformer is defined as ratio of _____________
a) primary turns to secondary turns
b) secondary current to primary current
c) secondary induced emf to primary induced emf
d) secondary terminal voltage to primary applied voltage
 

Answer: c

4. If a transformer is made to run on to a voltage which is more than the rated voltage _______________
a) its power factor will deteriorate
b) its power factor will increase
c) its power factor will remain unaffected
d) its power factor will be zero
 

Answer: a

5. Which of the following equation correctly represents the exact phasor diagram of transformer?
a) V1=E1+I1R1+jI1X1
b) V1=E1+I1R1+jI2X2
c) V2=E2+I1R1+jI1X1
d) V1=E1-I1R1+jI1X1
 

Answer: a

6. Approximate phasor diagram of a transformer is based on _____________
a) V1=E1+I1R1+jI1X1
b) V2=E2+I2R2+jI2X2
c) V1=V2+IR+jIX
d) V1=E1+I1R1+jI1X2
 

Answer: c

7. Hysteresis loss and eddy current loss is directly proportional to __________
a) f and f^2
b) f^2 and f
c) f and f
d) f^2 and f^2
 

Answer: a

8. What will happen to hysteresis loss if voltage is doubled, load is doubled and frequency is halved?
a) Will be twice
b) Will be halved
c) Will remain same
d) Will be four times
 

Answer: c

9. In a given transformer for given applied voltage, which of the following losses remain constant irrespective of load changes?
a) Friction and windage losses
b) Copper losses
c) Hysteresis and eddy current losses
d) Cannot be determined
 

Answer: c

10. On which of the following degree of mechanical vibrations produced by the lamination's of a transformer depends?
a) Tightness of clamping
b) Gauge of laminations
c) Size of laminations
d) Tightness of clamping, gauge and size of laminations
 

Answer: d