1. A transformer may have two or more ratings depending on
a) the type of winding used
b) the type of cooling used
c) the type of core used
d) the type of insulation used
ans. b
2. Conservator is used
a) to take up the expansion of oil due to temperature rise.
b) to act as an oil storage
c) for better cooling of the transformer
d) none of these
ans. a
3. Buchholz relay is placed
a) in between the conservator and the breathe
b) in between the tank and the conservator
c) in between the h.v. winding and the bushing
d) in between the l.v.winding and the bushing
ans. b
4. Buchholz relay is a
a) voltage sensitive device
b) current sensitive device
c) frequency sensitive device
d) gas actuated device
ans. d
5. Buchholz relay causes
a) tripping for major fault and alarm for minor faults
b) alarm for major fault and tripping for minor faults
c) tripping for both major and minor faults
d) alarm for both major and minor faults
ans. a
6. Transformer oil is used as
a) insulant only
b) coolant only
c) both insulant and coolant
d) insert medium
ans. c
7. Sludging of transformer oil means
a) continuous expansion and contraction due to heating and cooling
b) formation of semi-solid hydro-carbon due to heat and oxidation
c) decomposition of transformer oil under the influence of power arcs
d) evaporation of transformer oil due to heating
ans. b
8. To avoid breakdown of transformers under surges any one of the following except one may be adopted
a) use of surge absorbers
b) use of surge diverters
c) use of metal shields
d) Reinforcement to end-turn insulation.
ans. d
9. Repeated switching of transformers located nearer the generating station may cause
a) surface flashover of the bushings
b) mechanical distortion of the windings and subsequent turn to turn insulation failure
c) excessive temperature rise
d) intense local eddy currents in the core
ans. b
10. If the drying out operation of a transformer is unduly shortened and normal voltage is applied, then there is possibility of
a) inter-turn failure
b) winding to earth failure
c) terminal to terminal flashover
d) excessive overheating of the transformer
ans. a
a) the type of winding used
b) the type of cooling used
c) the type of core used
d) the type of insulation used
ans. b
2. Conservator is used
a) to take up the expansion of oil due to temperature rise.
b) to act as an oil storage
c) for better cooling of the transformer
d) none of these
ans. a
3. Buchholz relay is placed
a) in between the conservator and the breathe
b) in between the tank and the conservator
c) in between the h.v. winding and the bushing
d) in between the l.v.winding and the bushing
ans. b
4. Buchholz relay is a
a) voltage sensitive device
b) current sensitive device
c) frequency sensitive device
d) gas actuated device
ans. d
5. Buchholz relay causes
a) tripping for major fault and alarm for minor faults
b) alarm for major fault and tripping for minor faults
c) tripping for both major and minor faults
d) alarm for both major and minor faults
ans. a
6. Transformer oil is used as
a) insulant only
b) coolant only
c) both insulant and coolant
d) insert medium
ans. c
7. Sludging of transformer oil means
a) continuous expansion and contraction due to heating and cooling
b) formation of semi-solid hydro-carbon due to heat and oxidation
c) decomposition of transformer oil under the influence of power arcs
d) evaporation of transformer oil due to heating
ans. b
8. To avoid breakdown of transformers under surges any one of the following except one may be adopted
a) use of surge absorbers
b) use of surge diverters
c) use of metal shields
d) Reinforcement to end-turn insulation.
ans. d
9. Repeated switching of transformers located nearer the generating station may cause
a) surface flashover of the bushings
b) mechanical distortion of the windings and subsequent turn to turn insulation failure
c) excessive temperature rise
d) intense local eddy currents in the core
ans. b
10. If the drying out operation of a transformer is unduly shortened and normal voltage is applied, then there is possibility of
a) inter-turn failure
b) winding to earth failure
c) terminal to terminal flashover
d) excessive overheating of the transformer
ans. a
