| 1. | The speed of a synchronous motor can be changed by ? | |
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changing the supply voltage
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changing frequency
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changing the load
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changing supply terminals
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Report Question| 2. | In a synchronous motor running with fixed excitation, when the load is increased two times, its torque angle becomes approximately ? | |
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half
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twice
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four times
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no change
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| 3. | A three-phase synchronous motor will have ? | |
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one slip-rings
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two slip-rings
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no slip-rings
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three slip-rings
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| 4. | The maximum speed variation in a synchronous motor is ? | |
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zero
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2 percent
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4 percent
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6 percent
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| 5. | In a synchronous motor, the damping winding is generally used to ? | |
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provide starting torque only
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prevent hunting and provide the starting torque
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reduce the eddy currents
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reduce noise level
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| 6. | In a synchronous motor which loss varies with load ? | |
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Windage loss
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Bearing friction loss
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Core loss
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Copper loss
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| 7. | How much time (in sec) will be taken by 40 C of charge to pass through a point in a circuit, if a current of 8 A flows through it ? | |
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2
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3
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4
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5
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| 8. | Four capacitors of 15 mF are connected in parallel. What is the equivalent capacitance (in mF) of the combination ? | |
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60
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65
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70
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75
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| 9. | At 20 degree Celsius, aluminium wire has a resistance of 30 ohms. The temperature coefficient of resistance is 0.00305 per degree Celsius. What is the approximate resistance of the wire (in ohms) at 30 degree Celsius ? | |
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28
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31
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35
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45
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| 10. | On which supply does the appliances based on heating effect of electric current work ? | |
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AC
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DC
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Both AC and DC
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None of these
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