| 1. | If two alternators are running in parallel and the excitation of one of the alternators is increased, then ? | |
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power output will decrease
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Wattless component will change
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machine with excess excitation will burn
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both machines will start vibrating
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Report Question| 2. | In an alternator, when the load power factor is unity ? | |
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the armature flux will be demagnetising
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the armature flux will be crossmagnetising
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the armature flux will reduce to zero
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the armature flux will have square wave form
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| 3. | If the voltage of one of the two machines running in synchronism is suddenly increased ? | |
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both machines will stop
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synchronising torque will be produced to restore further synchronism
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the machines will burn
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none of the above
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| 4. | The regulation of an alternator is ? | |
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the increase in terminal voltage when load is thrown off
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the reduction in terminal voltage when alternator is loaded
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the variation of terminal voltage under the condition of maximum and minimum excitation
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the change in terminal voltage from lagging power factor to leading power factor
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| 5. | Leakage reactance of the armature of a salient pole synchronous machine which varies with the position of the rotor is due to ? | |
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leakage flux which remains within the slot
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leakage flux of end connections
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leakage flux which comes out of slot teeth, crosses the air gap and enters pole faces
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none of the above
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| 6. | In air-crafts, alternators have operating frequency of ? | |
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800 Hz
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400 Hz
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60 Hz
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60 Hz
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| 7. | The slip rings employed in a 3-phase alternator in hydro -station are insulated for ? | |
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low voltage
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very low voltage
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full armature voltage
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extra high tension voltage
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| 8. | For a given output steam turbo-alternators are much smaller is size than water turbine-alternators because ? | |
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steam turbo-alternators are built with smaller capacities
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steam turbo-alternators have long rotors
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steam turbo-alternators run at high speed
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all of the above
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| 9. | An alternator is said to be over excited when it is operating at ? | |
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lagging power factor
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leading power factor
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unity power factor
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lagging to 'leading power factor
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| 10. | If the space flux distribution is non sinusoidal, e.m.f. induced in the distributed winding ? | |
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will be less sinusoidal than flux distribution
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will be more sinusoidal than flux distribution
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will be equally non-sinusoidal
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none of the above
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