| 1. | Eddy currents are induced in the pole shoes of a D.C machine due to ? | |
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oscillating magnetic field
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pulsating magnetic flux
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relative rotation between field and armature
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all above
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Report Question| 2. | In a D.C. generator the actual flux distribution depends upon ? | |
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size of air gap
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shape of the pole shoe
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clearance between tips of the adjacent pole shoes
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all of the above
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| 3. | A cumulatively compounded long shunt generator when operating as a motor would be ? | |
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cumulatively compounded long shunt
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differentially compounded long shunt
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cumulatively compounded short shunt
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differentially compounded short shunt
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| 4. | In a D.C. machine, short-circuited field coil will result in ? | |
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odour of burning insulation
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unbalanced magnetic pull producing vibrations
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reduction of generated :voltage for which excitation has to be increased to maintain the voltage
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all above
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| 5. | Compensating windings are used in DC generators ? | |
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mainly to reduce the eddy currents by providing local short-circuits
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to provide path for the circulation of cooling air
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to neutralise the cross-magnetising effect of the armature reaction
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none of the above
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| 6. | The following constitute short-circuit in the armature winding ? | |
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Insulation failure between two commutator bars
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Insulation failure between two turns of a coil
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Two of more turns of the same coil getting grounded
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All of the above
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| 7. | Welding generator will have ? | |
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lap winding
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wave winding
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delta winding
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duplex wave winding
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| 8. | The terminal voltage of a D.C. shunt generator drops on load because of all of the following reasons except ? | |
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armature reaction
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armature resistance drop
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field weakening due to armature reaction and armature
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commutation
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| 9. | If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be ? | |
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demagnetisation only
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cross magnetisation as well as magnetisation
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cross magnetisation as well as demagnetising
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cross magnetisation only
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| 10. | A D.C. generator can be considered as ? | |
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rectifier
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prime mover
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rotating amplifier
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power pump
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