1. For cold rolled grain-oriented silicon steel metered overlap is preferable for the core-yoke joint as
a) it improves mechanical strength
b) it makes better use of core space
c) it reduces magnetostriction
d) it reduces magnetizing current and also the core-losses
ans. d
2. The direction of central phase winding of a three-phase shell type transformer is reversed with respect to the outer phases to
a) save considerable amount of core material
b) reduce leakage fluxes
c) reduce short circuit forces
d) minimise eddy current loss
ans. a
3. Low voltage windings are placed nearer to the core in the case of concentric windings because it reduces
a) hysteresis loss
b) eddy current loss
c) insulation requirement
d) leakage fluxes
ans. c
4. Spiral winding is suitable only for windings
a) carrying very low current
b) carrying very high current
c) rated for high voltage
d) rated for low voltage
ans. b
5. Helical winding is suitable for
a) low voltage winding of small transformers
b) high voltage winding of small transformers
c) low voltage winding of large transformers
d) high voltage winding of large transformers
ans. c
6. Cross over winding is suitable for
a) low voltage winding of small transformers
b) high voltage winding of small transformers
c) low voltage winding of large transformers
d) high voltage winding of large transformers
ans. c
7. Continuous disc winding is suitable for
a) low voltage winding of small transformers
b) high voltage winding of small transformers
c) low voltage winding of large transformers
d) high voltage winding of large transformers
ans.d
8. In general , for all sizes of distribution transformer, it is preferable to use
a) plain sheet steel tanks
b) tubed tanks
c) corrugated tanks
d) radiator tanks
ans. b
9. For small power transformers, it is preferable to use
a) tubed tanks
b) corrugated tanks
c) radiator tanks
d) tanks with separate coolers
ans. a
10. For large power transformer, it is preferable to use
a) tubed tanks
b) corrugated tanks
c) radiator tanks
d) tanks with separate coolers
ans. d
a) it improves mechanical strength
b) it makes better use of core space
c) it reduces magnetostriction
d) it reduces magnetizing current and also the core-losses
ans. d
2. The direction of central phase winding of a three-phase shell type transformer is reversed with respect to the outer phases to
a) save considerable amount of core material
b) reduce leakage fluxes
c) reduce short circuit forces
d) minimise eddy current loss
ans. a
3. Low voltage windings are placed nearer to the core in the case of concentric windings because it reduces
a) hysteresis loss
b) eddy current loss
c) insulation requirement
d) leakage fluxes
ans. c
4. Spiral winding is suitable only for windings
a) carrying very low current
b) carrying very high current
c) rated for high voltage
d) rated for low voltage
ans. b
5. Helical winding is suitable for
a) low voltage winding of small transformers
b) high voltage winding of small transformers
c) low voltage winding of large transformers
d) high voltage winding of large transformers
ans. c
6. Cross over winding is suitable for
a) low voltage winding of small transformers
b) high voltage winding of small transformers
c) low voltage winding of large transformers
d) high voltage winding of large transformers
ans. c
7. Continuous disc winding is suitable for
a) low voltage winding of small transformers
b) high voltage winding of small transformers
c) low voltage winding of large transformers
d) high voltage winding of large transformers
ans.d
8. In general , for all sizes of distribution transformer, it is preferable to use
a) plain sheet steel tanks
b) tubed tanks
c) corrugated tanks
d) radiator tanks
ans. b
9. For small power transformers, it is preferable to use
a) tubed tanks
b) corrugated tanks
c) radiator tanks
d) tanks with separate coolers
ans. a
10. For large power transformer, it is preferable to use
a) tubed tanks
b) corrugated tanks
c) radiator tanks
d) tanks with separate coolers
ans. d
