253.  The purpose of performing Sumpner's test is mainly to find out
A. regulation of the transformer
B. efficiency of the transformer
C. the temperature rise on full load economically
D. none of the above

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254.  When 240 V D.C. supply is given to an unloaded 220 V, 50 Hz transformer
A. secondary will carry heavy current
B. primary will carry heavy current and may possibly burn
C. we will get A.C. voltage on secondary side according to turn ratio
D. we will get high voltage on secondary side

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255. In a transformer, if the magnitude of magnetizing current is more
A. its power factor will become low on leading side
B. its power factor will become low on lagging side
C. it has no effect on the power factor of the transformer
D. none of the above

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256. In measuring voltage or current by means of instrument transformer
A. only ratio errors need be considered
B. both ratio as well as phase angle error need to be considered
C. either of the above
D. none of the above

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257. In which of the following the highest rating transformer is likely to find application?
A. Transmission
B. Substation
C. Generator
D. Distribution

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258. In a transformer maximum voltage regulation occurs when the power factor of the load is
A.0.4
B. lagging
C. leading
D. unity

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259. In a transformer minimum voltage regulation occurs when the power factor of the load is
A. leading
B. lagging
C.0.8
D. unity

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