| 1. | A stationary alternator should not be connected to a live bus bar because it ? | |
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will get short-circuited
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will disturb generated e.m.fs. of other alternators connected in parallel
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is likely to run as a synchronous motor
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will decrease but-bar voltage though momentarily
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Report Question| 2. | If the steam supply of an alternator running in parallel with another identical alternator is increased keeping its excitation constant, then ? | |
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it will supply greater portion of the load
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the power factor would be decreased
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it would over-run the other alternator
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its rotor will fallback in phase with respect to the other machine
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| 3. | Which of the following is the common synchronous speed in r.p.m. between 50 Hz and be 60 Hz alternators ? | |
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200
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300
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600
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900
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| 4. | Which of the following coils in an alternator will have e.m.f closer to sine waveform ? | |
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Distributed winding in full pitch coils
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Distributed winding in short pitch coils
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Concentrated winding in full pitch coils
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Concentrated winding in short pitch coils
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| 5. | An alternator running in parallel with other alternators all having automatic voltage regulators is to be taken off the bus. The usual procedure before opening the switch is to ? | |
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reduce the power fed to the prime mover
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reduce alternator excitation
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increase alternator excitation
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none of the above
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| 6. | In an alternator the armature reaction is mainly influenced by ? | |
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the power factor of the load
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short-circuit ratio
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speed of the alternator
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total current drawn
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| 7. | What kind of rotor is most suitable for turbo-alternators which are designed to run at high speed ? | |
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Salient pole type
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Non-salient pole type
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Either (a) or (b)
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None of the above
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| 8. | The frequency of voltage generated in large alternators is ? | |
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50 Hz
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60 Hz
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in kilo cycles
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in mega cycles
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| 9. | Fleming's left hand rule may be applied to an electric generator to find out direction of ? | |
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magnetic field
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induced e.m.f,
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rotor rotation
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none of the above
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| 10. | The choice of field construction, in an alternator, is basically determined by ? | |
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generated voltage needed by the customers
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comparative cost of the field systems
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supply frequency required by the consumers
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the kind of energy source available in the geographic location
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