| 1. | The magnitude of field flux in a 3-phase synchronous motor ? | |
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remains constant at all loads
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varies with speed
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varies with the load
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varies with power factor
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Report Question| 2. | A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because ? | |
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synchronous motor has no slip
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stator supply is not required to produce magnetic field
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mechanical load on the rotor remains constant
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synchronous motor has large air gap
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| 3. | A synchronous motor can develop synchronous torque ? | |
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when under loaded
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while over-excited
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only at synchronous speed
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below or above synchronous speed
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| 4. | When a 3-phase synchronous generator is supplying a zero power factor lagging load, the armature field affects the main field in the following way ? | |
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augments it directly
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directly opposes it
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cross-magnetises it
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none of the above
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| 5. | If in a synchronous motor, driving mechanical load and drawing current at lagging power factor from constant voltage supply, its field excitation is increased, then its power factor ? | |
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become more
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become less
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remain constant
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none of the above
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| 6. | Under which of the following conditions hunting of synchronous motor is likely to occur ? | |
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Periodic variation of load
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Over-excitation
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Over-loading for long periods
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Small and constant load
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| 7. | ln a synchronous motor which loss varies with load ? | |
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Windage loss
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Bearing friction loss
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Copper loss
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Core loss
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| 8. | A synchronous motor will always stop when ? | |
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supply voltage fluctuates
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load in motor varies
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excitation winding gets disconnected
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supply voltage frequency changes
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| 9. | The armature current of the synchronous motor has higher values for ? | |
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high excitation only
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low excitation only
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both (a) and (b)
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none of the above
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| 10. | In which of the following motors the stator and rotor magnetic field rotate at the same speed ? | |
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Universal motor
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Synchronous motor
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Induction motor
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Reluctance motor
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