196. An ideal synchronous motor has no starting torque because the

1. 1. rotor is made up of salient poles

   
   
   

   2. relative velocity between the startor and the rotor mmf's is zero

   
   
   

   3. relative velocity between stator and rotor mmf's is not zero

   
   
   

   4. rotor winding is highly reactive.

   
   
   

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   NA

   Correct Option: C

   NA

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197. A three phase, 8 pole induction motor runs on 50Hz supply. The rotor bar current makes 150 complete cycles per minute. Then the rotor moves at a speed of

1. 1. 710 rpm

   
   
   

   2. 713.5 rpm

   
   
   

   3. 712.5 rpm

   
   
   

   4. none of these

   
   
   

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   NA

   Correct Option: D

   NA

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198. In three phase slip ring induction motor input is 440 V and the voltage at the slip rings is 110 V. If an input of 110 V is given to the slip rings, the startor voltage would be

1. 1. 500 V

   
   
   

   2. nearly equal to 440 V

   
   
   

   3. nearly equal to 110 V

   
   
   

   4. zero

   
   
   

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   NA

   Correct Option: B

   NA

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199. In a shaded-pole induction motor, the rotor runs from the

1. 1. shaded portion to the unshaded portion of the pole while the flux in the former leads that of the latter

   
   
   

   2. shaded portion to the unshaded portion of the pole while the flux in the former lags that in the latter

   
   
   

   3. unshaded portion to the shaded portion while the fluxing the former leads that in the latter

   
   
   

   4. unshaded portion to the shaded portion while the flux in the former lags that in the latter

   
   
   

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   NA

   Correct Option: D

   NA

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200. A single-phase startor winding when excited with ac voltage produces

1. 1. a single rotating field rotating at synchronous speed.

   
   
   

   2. two rotating fields rotating at synchronous speed in opposite directions.

   
   
   

   3. two rotating fields rotating in the same direction but at different speeds '

   
   
   

   4. two rotating fields rotating in opposite directions but with difference speeds.

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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