1. For a given application , the transformation ratio of a transformer
a) is fixed but not constant
b) is constant but not fixed
c) is dependent on secondary load
d) depends on which winding is used as primary
ans. a
2. Two transformers when operating in parallel will share the load depending upon their
a) magnetizing current
b) leakage current
c) per unit impedance
d) efficiency
ans. c
3. Ferrite cores are used in high frequency transformer because it has
a) low permeability
b) high hysteresis
c) low resistance
d) high resistance
ans. d
4. The size of transformer core will depend on
a) frequency
b) flux density of the core material
c) area of the core
d) both A and B current
ans. d
5. Two transformers operating in parallel will share the load depending upon their
a) efficiency also
b) ratings also
c) leakage reactance
d) none of these
ans. b
6. In a transformer the purpose of breather is to
a) extract moisture from the air
b) to take insulating oil form the conservator
c) to provide cooling to the winding
d) to provide insulation to the winding
ans. a
7. Conservator consists of
a) an air-tight metal drum fixed at the top of the tank
b) drum placed at the bottom of the tank
c) overload protection
d) none of these
ans. a
8. The nominal short-circuit voltage of the transformer is defined as the precentage of
a) the test voltage
b) the rated secondary voltage
c) the rated primary voltage
d) the nominal transformation ratio
ans. c
9. The efficiency in transformer is maximum at
a) full load
b) half the full load
c) one third the full load
d) no load
ans. a
10. No-load test on a transformer is carried out to determine
a) copper loss
b) full-load current
c) magnetizing current
d) efficiency of the transformer
ans. c
a) is fixed but not constant
b) is constant but not fixed
c) is dependent on secondary load
d) depends on which winding is used as primary
ans. a
2. Two transformers when operating in parallel will share the load depending upon their
a) magnetizing current
b) leakage current
c) per unit impedance
d) efficiency
ans. c
3. Ferrite cores are used in high frequency transformer because it has
a) low permeability
b) high hysteresis
c) low resistance
d) high resistance
ans. d
4. The size of transformer core will depend on
a) frequency
b) flux density of the core material
c) area of the core
d) both A and B current
ans. d
5. Two transformers operating in parallel will share the load depending upon their
a) efficiency also
b) ratings also
c) leakage reactance
d) none of these
ans. b
6. In a transformer the purpose of breather is to
a) extract moisture from the air
b) to take insulating oil form the conservator
c) to provide cooling to the winding
d) to provide insulation to the winding
ans. a
7. Conservator consists of
a) an air-tight metal drum fixed at the top of the tank
b) drum placed at the bottom of the tank
c) overload protection
d) none of these
ans. a
8. The nominal short-circuit voltage of the transformer is defined as the precentage of
a) the test voltage
b) the rated secondary voltage
c) the rated primary voltage
d) the nominal transformation ratio
ans. c
9. The efficiency in transformer is maximum at
a) full load
b) half the full load
c) one third the full load
d) no load
ans. a
10. No-load test on a transformer is carried out to determine
a) copper loss
b) full-load current
c) magnetizing current
d) efficiency of the transformer
ans. c
