| 1. | The speed of a series motor at no load is ? | |
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infinity
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4000 r.p.rn.
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2000 r.p.m.
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1000 r.p.m.
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Report Question| 2. | In D.C. machines the residual magnetism is of the order of ? | |
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2 to 3 per cent
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10 to 15 per cent
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20 to 25 per cent
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50 to 75 per cent
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| 3. | Which of the following statements is correct, in case of a D.C. series motor ? | |
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It should be directly connected to the load
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It may run away if its field becomes open
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It is a constant speed motor
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It cannot be used where high starting torque is required
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| 4. | Which D.C. motor will have least percentage increase of input current, for the same percentage increase in the torque ? | |
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Shunt motor
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Series motor
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Cumulative compound motor
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Separately excited motor
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| 5. | If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens ? | |
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nothing will happen to the motor
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this will make armature to take heavy current, possibly burning it
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this will result in excessive speed, possibly" destroying armature due to excessive centrifugal stresses
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motor will run at very "slow speed
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| 6. | Which loss in a D.C. generator varies with load ? | |
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Copper loss
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Eddy current loss
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Hysteresis loss
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Windage loss
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| 7. | In which of the following tests only one motor is required ? | |
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Brake test
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Hopkinson's test
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Field's test
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Swinburne's test
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| 8. | Three point starter can be used for ? | |
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series motor only
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shunt motor only
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compound motor only
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both shunt and compound motor
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| 9. | In DC. motor which of the following can sustain the maximum temperature rise ? | |
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Slip rings
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Commutator
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Field winding
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Armature winding
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| 10. | Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of ? | |
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D.C. series motor
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D.C. shunt motor
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induction motor
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all of above motors
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