| 1. | The purpose of a breather in a transformer is to ? | |
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provide cooling to the winding
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take insulting oil from the conservator
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Provide insulation to the winding
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extract moisture from the air
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Report Question| 2. | In a transformer on no-load, the input voltage ? | |
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is always at 60º to the magnetizing current
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is in phase with magnetizing current
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leads the magnetizing current by 90°
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lags the magnetizing current by 90º
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| 3. | Current transformers for meters and relays usually have ? | |
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1 : 2 ratio
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5 : 1 ratio
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5-A secondaries
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15-A secondaries
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| 4. | ln which of the following the highest rating transformer is likely to find application ? | |
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Transmission
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Substation
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Generator
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Distribution
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| 5. | ln a transformer minimum voltage regulation occurs when the power factor of the load is ? | |
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leading
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lagging
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0.8
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unity
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| 6. | Cross-over windings are used for ? | |
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high voltage winding of large rating transformers
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high voltage winding of small rating transformers
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low voltage winding of small rating transformers
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none of these
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| 7. | Simple porcelain bushings are used for transformers upto ? | |
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11 kV
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132 kV
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400 kV
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none of the above
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| 8. | A transformer is working at its full load and its efficiency is also maximum. Its iron loss is 1 kW, its copper loss at half load will be ? | |
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0.1 kW
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0.2 kW
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0.25 kW
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0.5 kW
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| 9. | A transformer having a turn ratio 1: 5 and a resistance of 1000 ? is connected across the secondary terminals, the resistance offered to a current flowing in the primary will be ? | |
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10 ?
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20 ?
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40 ?
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60 ?
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| 10. | For minimum weight of a transformer, the weight of iron should be ? | |
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equal to the weight of copper
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less than weight of copper
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greater than weight of copper
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zero
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