| 1. | The angle between the rotating stator flux and rotor poles is called ...... angle ? | |
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torque
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obtuse
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synchronizing
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power factor
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Report Question| 2. | The efficiency of a properly designed synchronous motor will usually fall in range ? | |
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60 to 70%
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75 to 80%
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85 to 95%
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99 to 99.5%
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| 3. | An over-excited synchronous motor is used for ? | |
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fluctuating loads
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variable speed loads
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low torque loads
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power factor corrections
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| 4. | The rotor copper losses, in a synchronous motor, are met by ? | |
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dc source
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armature input
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motor input
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supply lines
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| 5. | Hunting in a synchronous motor takes place ? | |
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when supply voltage fluctuates
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when load varies
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when power factor is unity
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motor is under loaded
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| 6. | A synchronous motor can be made self starting by providing ? | |
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damper winding on rotor poles
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damper winding on stator
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damper winding on stator as well as rotor poles
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one of the above
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| 7. | The working of a synchronous motor is similar to ? | |
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gear train arrangement
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transmission of mechanical power by shaft
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distribution transformer
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turbine
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| 8. | For V-curves for a synchronous motor the graph is drawn between ? | |
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field current and armature current
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terminal voltage and load factor
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power factor and field current
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armature current and power factor
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| 9. | Under which of the following conditions hunting of synchronous motor is likely to occur ? | |
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Periodic variation of load
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Over-excitation
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Over-loading for long periods
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Small and constant load
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| 10. | Synchronous motors are generally not self-starting because ? | |
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the direction of rotation is not fixed
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the direction of instantaneous torque reverses after half cycle
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starter cannot be used on these machines
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starting winding is not provided on the machines
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