| 1. | What is the disadvantage of starting an induction motor with a star-delta starter ? | |
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The starting torque is one third of the torque in case of the delta connection
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During starting high losses are produced
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The starting torque increases and the motor runs with jerks
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None of the above
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Report Question| 2. | In a 3-phase induction motor, iron loss ? | |
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ln rotor is negligible as compared to that in stator
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in stator does not occur
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in rotor is equal to iron loss is stator
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in rotor is much more than the iron loss in stator
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| 3. | Phase advancers are used with induction motors to ? | |
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reduce noise
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reduce vibrations
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reduce copper losses
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improve power factor
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| 4. | The purpose of using short-circuit gear is ? | |
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to short circuit the rotor at slip rings
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to short circuit the starting resistances in the starter
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to short circuit the stator phase of motor to form star
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none of the above
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| 5. | Insertion of resistance in the stator of an induction motor ? | |
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increases the load torque
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decreases the starting torque
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increases the starting torque
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none of the above
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| 6. | A change of 4% of supply voltage to an induction motor will produce a change of approximately ? | |
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4% in the rotor torque
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8% in the rotor torque
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12% in the rotor torque
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16% in the rotor torque
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| 7. | The stating torque of the slip ring induction motor can be increased by adding ? | |
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external inductance to the rotor
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external resistance to the rotor
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external capacitance to the rotor
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both resistance and inductance to rotor
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| 8. | The maximum torque in an induction motor depends on ? | |
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frequency
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rotor inductive reactance
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square of supply voltage
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all of the above
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| 9. | The term 'cogging' is associated with ? | |
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three phase transformers
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compound generators
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DC. series motors
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induction motors
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| 10. | The frame of an induction motor is usually made of ? | |
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silicon steel
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cast iron
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aluminium
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bronze
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