| 1. | What is the disadvantage of the speed control of slip-ring induction motor with the help of resistances in the rotor circuit ? | |
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By using this method the speed can be easily controlled
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This method is associated with high losses
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With reductions in torque the speed decreases considerably
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None of the above
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Report Question| 2. | A squirrel cage induction motor running on no-load is loaded, which of the following statements is incorrect ? | |
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Current in the rotor bars decreases
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Motor speed decreases
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Torque developed by the rotor increases
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Stator flux cuts the rotor bars more rapidly
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| 3. | Each of the following statements regarding stator flux of an induction motor is true except ? | |
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Its induces e.m.f. in the rotor bars
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Its magnitude depends on the motor load
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It is constant in magnitude
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It revolves around the stator at synchronous speed
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| 4. | The rotor of an induction motor cannot run with synchronous speed because ? | |
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Lenz's law would be violated
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induction motor would then become synchronous motor
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rotor torque would then become zero
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air friction prevents it to do so
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| 5. | The advantage of a slip-ring induction motor over a squirrel cage induction motor is that ? | |
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it bas higher efficiency
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it has higher power factor
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it can be started with the help of rotor resistance stater
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none of the above
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| 6. | Size of a high speed motor as compared to low speed motor for the same H.P. will be ? | |
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bigger
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smaller
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same
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any of the above
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| 7. | Less maintenance troubles are experienced in case of ? | |
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slip ring induction motor
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squirrel cage induction motor
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both (a) and (b)
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none of the above
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| 8. | In a three-phase induction motor, the relative speed ยท of stator flux with respect to ...... is zero ? | |
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space
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rotor
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stator winding
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rotor flux
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| 9. | ln a 3-phase induction motor which of the following statements, regarding frequency of induced rotor e.m.f is incorrect ? | |
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lts speed varies inversely as slip
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It is zero at synchronous speed
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It is directly dependent on slip
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It is maximum at stand still
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| 10. | If the rotor is open in a squirrel cage motor, it ? | |
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will run at very high speed
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will run at very slow speed
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will not run
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will make noise
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