| 1. | The saving in copper achieved by converting two winding transformer into an auto-transformer is determined by ? | |
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load on the secondary
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voltage transformation ratio
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size of the transformer core
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magnetic quality of core material
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Report Question| 2. | ln a three-phase delta transformer, one of the phases burns up. The transformer will supply ? | |
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zero output
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20 percent of its output rating
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its full output rating
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none of the above
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| 3. | The advantage of putting tappings at the phase ends of a transformer is ? | |
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to reduce the number of bushings
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to obtain better regulation
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to obtain fine variation of voltage
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to operate with ease
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| 4. | Which of the following is not a routine test on transformers ? | |
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Core insulation voltage test
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Impedance test
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Radio interference test
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Polarity test
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| 5. | A distribution transformer has low flux density because ? | |
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It is constantly connected to the supply
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it is required to give better power factor
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it is normally a small transformer
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iron is quite cheap
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| 6. | A transformer is working at its maximum efficiency. Its iron loss is 1 kW. Its copper Joss will be ? | |
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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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1 kW
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| 7. | Minimum voltage regulation occurs when the power factor of the load is ? | |
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unity
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lagging
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leading
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zero
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| 8. | ln a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are ? | |
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Hysteresis and eddy current losses
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friction and windage losses
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copper losses
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none of the above
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| 9. | A shell-type transformer has ? | |
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high eddy current losses
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reduced magnetic leakage
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negligibly hysteresis losses
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none of the above
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| 10. | Open circuit test on transformers is conducted to determine ? | |
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hysteresis losses
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copper losses
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core losses
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eddy current losses
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