| 1. | A transformer oil must be free from ? | |
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sludge
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odour
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gases
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moisture
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Report Question| 2. | Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in ? | |
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short-circuiting of the secondary
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power factor of one of the transformers is leading while that of the other lagging
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transformers having higher copper losses will have negligible core losses
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loading of the transformer not in proportion to their kVA ratings
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| 3. | An ideal transformer is one which has ? | |
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no losses and magnetic leakage
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interleaved primary and secondary windings
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a common core for its primary and secondary windings
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core of stainless steel and winding of pure copper metal
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| 4. | The kVA rating ratio of transformers operating in parallel, as a general rule, should be within ? | |
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5 : 1
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4 : 1
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3 : 1
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2 : 1
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| 5. | In which of the following transformer part of primary winding also serves as the secondary winding ? | |
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Potential transformer
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Auto transformer
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Step-up transformer
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Current transformer
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| 6. | The purpose of performing Sumpner's test is mainly to find out ? | |
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regulation of the transformer
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efficiency of the transformer
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the temperature rise on full load economically
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none of the above
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| 7. | The value of flux involved in the e.m.f. equation of a transformer is ? | |
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average value
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r.m.s. value
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maximum value
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instantaneous value
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| 8. | When a given transformer is run at its rated voltage but reduced frequency, its ? | |
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flux density remains unaffected
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iron losses are reduced
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core flux density is reduced
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core flux density is increased
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| 9. | The transformer ratings are usually expressed in terms of ? | |
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volts
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amperes
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kW
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kVA
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| 10. | The purpose of providing an iron core in a transformer is to ? | |
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provide support to windings
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reduce hysteresis loss
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decrease the reluctance of the magnetic path
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reduce eddy current losses
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