| 1. | Rotor rheostat control method of speed control is used for ? | |
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squirrel-cage induction motors only
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slip ring induction motors only
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both (a) and (b)
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none of the above
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Report Question| 2. | The good power factor of an induction motor can be achieved if the average flux density in the air gap is ? | |
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absent
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small
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large
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infinity
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| 3. | The power scale of circle diagram of an induction motor can be found from ? | |
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stator resistance test
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no-load test only
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short-circuit test only
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none of the above
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| 4. | Speed variations of a squirrel cage induction motor are essentially similar to those of ? | |
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D.C. shunt motor
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D.C. series motor
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synchronous motor
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differential compound motor
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| 5. | When a squirrel cage induction motor fails to start which of the following could not be the reason for the same ? | |
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Uneven all gap
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Blown fuses
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Overload
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One or two phase open
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| 6. | The stator frame in an induction motor is used ? | |
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to protect the whole machine
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to ventilate the armature
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as a return path for the flux
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to hold the armature stampings stator
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| 7. | Synchronous speed is defined as ? | |
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the speed of a synchronous motor
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the natural speed at which a magnetic field rotates
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the speed of the rotor of an induction motor
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the speed of an induction motor at no load
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| 8. | In moist surroundings which frame of motor will be preferred ? | |
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Open type
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Totally enclosed fan cooled
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Drip proof
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Splash proof
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| 9. | In case single phasing occurs in delta connected motor ? | |
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one phase will be seriously overloaded and two others will be slightly overloaded
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two phases will be seriously overloaded and there will be no current in the third phase
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there will be no current in one phase
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there will be no current in two phases
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| 10. | Which of the following features of induction motor helps in preventing cogging of motor ? | |
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Skewed slots
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High slip
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Use of better insulating materials
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Large number of poles
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