| 1. | Power transformers are generally designed to have maximum efficiency around ? | |
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no-load
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half-load
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near full-load
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10% overload
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Report Question| 2. | Two transformers operating in parallel will share the load depending upon their ? | |
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leakage reactance
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per unit impedance
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efficiencies
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ratings
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| 3. | Power transformers are designed to have maximum efficiency at ? | |
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nearly full load
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70% full load
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50% full load
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no load
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| 4. | No-load on a transformer is carried out to determine ? | |
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copper loss
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magnetising current
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magnetising current and loss
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efficiency of the transformer
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| 5. | The hum in a transformer is mainly attributed to ? | |
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load changes
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oil in the transformer
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oil in the transformer
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mechanical vibrations
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| 6. | Which of the following materials is suitable for the manufacture of transformer and large turbo-alternator ? | |
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Cast iron
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Cast steel
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Cold rolled grain oriented steel
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Hot rolled grain oriented steel
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| 7. | Reduction in core losses and increase in permeability are obtained with transformer employing ? | |
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core built up of laminations of cold rolled grain oriented steel
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core built-up of laminations of hot rolled sheet
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either of the above
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none of the above
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| 8. | For given applied voltage, with the increase in frequency of the applied voltage ? | |
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eddy current loss will decrease
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eddy current loss will increase
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eddy current loss will remain unchanged
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none of the above
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| 9. | Which of the following statements about a transformer having a small short-circuit voltage is true ? | |
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A low short-circuit current flows through the transformer
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A high short-circuit current flows through the transformer
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The transformer has high copper losses during the operation
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The transformer has high iron losses during the operation
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| 10. | The humming sound in a transformer is mainly due to ? | |
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magnetostriction
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walls of the tank
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oil of the transformer
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laminations of the transformer
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