Top 80+ Solved Transformers MCQ Questions Answer
Q. Gas is usually not liberated due to dissociation of transformer oil unless the oiltemperature exceeds
a. 50°C
b. 80°C
c. 100°C
d. 150°C
Q. The main reason for generation of harmonics in a transformer could be
a. fluctuating load
b. poor insulation
c. mechanical vibrations
d. saturation of core
Q. Distribution transformers are generally designed for maximum efficiency around
a. 90% load
b. zero load
c. 25% load
d. 50% load
Q. Which of the following property is not necessarily desirable in the material fortransformer core ?
a. Mechanical strength
b. Low hysteresis loss
c. High thermal conductivity
d. High permeability
Q. Star/star transformers work satisfactorily when
a. load is unbalanced only
b. load is balanced only
c. on balanced as well as unbalanced loads
d. none of the above
Q. Delta/star transformer works satisfactorily when
a. load is balanced only
b. load is unbalanced only
c. on balanced as well as unbalanced loads
d. none of the above
Q. Buchholz's relay gives warning and protection against
a. electrical fault inside the transformer itself
b. electrical fault outside the transformer in outgoing feeder
c. for both outside and inside faults
d. none of the above
Q. The magnetising current of a transformer is usually small because it has
a. small air gap
b. large leakage flux
c. laminated silicon steel core
d. fewer rotating parts
Q. Which of the following does not change in an ordinary transformer ?
a. Frequency
b. Voltage
c. Current
d. Any of the above
Q. Which of the following properties is not necessarily desirable for the material fortransformer core ?
a. Low hysteresis loss
b. High permeability
c. High thermal conductivity
d. Adequate mechanical strength
Q. 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
Q. The path of the magnetic flux in transformer should have
a. high reluctance
b. low reactance
c. high resistance
d. low resistance
Q. Noise level test in a transformer is a
a. special test
b. routine test
c. type test
d. none of the above
Q. Which of the foJIowing is not a routine test on transformers ?
a. Core insulation voltage test
b. Impedance test
c. Radio interference test
d. Polarity test
Q. A transformer can have zero voltage regulation at
a. leading power factor
b. lagging power factor
c. unity power factor
d. zero power factor