| 1. | Spiral core transformer which has core made up of steel strip has the following advantage ? | |
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Less weight
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Lighter construction
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Minimum losses
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All above
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View Answer
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Report Question| 2. | In a transformer an insulating material may fail due to ? | |
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moisture
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dust
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voids in the winding
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any of the above
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| 3. | An auto-transformer is preferred to a conventional 2-winding transformer ? | |
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where ratio of transformation is low
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where it is required to isolate the two windings electrically
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because it is much safer to use an auto-transformer
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where large number of secondary taps are needed
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| 4. | ln a transformer, if the magnitude of magnetizing current is more ? | |
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its power factor will become low on leading side
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Its power factor will become low on lagging side
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it has no effect on the power factor of the transformer
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none of the above
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| 5. | The degree of mechanical vibrations produced by the laminations of a transformer depends on ? | |
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tightness of clamping
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gauge of laminations
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size of laminations
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all of the above
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| 6. | The chemical used in breather for transformer should have the quality of ? | |
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ionizing air
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absorbing moisture
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cleansing the transformer oil
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cooling the transformer oil
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| 7. | In the transformer the function of a conservator is to ? | |
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provide fresh air for cooling the transformer
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supply cooling oil to transformer in time of need
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protect the transformer from damage when oil expends due to heating
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none of the above
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| 8. | No-load current in a transformer ? | |
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lags behind the voltage by about 75º
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leads the voltage by about 75º
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lags behind the voltage by about 15º
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leads the voltage by about 15º
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| 9. | Sumpner's test is conducted on transformers to determine ? | |
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temperature
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stray losses
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all-day efficiency
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none of the above
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| 10. | The no-load current drawn by transformer is usually what per cent of the full-load current ? | |
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0.2 to 0.5 per cent
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2 to 5 percent
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12 to 15 per cent
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20 to 30 per cent
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