| 1. | A D.C. series motor, as compared to shunt and compound motors, has the highest torque at the start because of its comparatively ? | |
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stronger series field
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lower armature resistance
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large armature current
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fewer series turns
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Report Question| 2. | In Field's test for series motors one motor drives the other machine as ? | |
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cumulative compound generator
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differential compound generator
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separately excited generator
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series generator
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| 3. | A wide and very sensitive speed control is usually required in case of ? | |
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elevators
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steel rolling mills
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colliery winders
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all of the above
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| 4. | Speed control of a cumulatively compounded DC motor can be effected through change of ? | |
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field resistance
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armature resistance
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armature voltage
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any of the above
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| 5. | Which of the following, in a D.C. motor, can sustain the maximum temperature rise ? | |
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Commutator
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armature windings
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Slip rings
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Field windings
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| 6. | The rated speed of a given D.C. shunt motor is 900 r.p.m. To run this machine at 1000 r.p.m., which of the following speed control scheme will be used ? | |
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Ward-Leonard control
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Armature current resistance control
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Field resistance control
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None of the above
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| 7. | The total losses in a well designed D.C. generator of 10 kW will be nearly ? | |
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100 W
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500 W
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1000 W
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1500 W
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| 8. | Which motor has the poorest speed control ? | |
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Differentially compounded motor
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Cumulatively compounded motor
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Shunt motor
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Series motor
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| 9. | ln case-the conditions for maximum power for a D.C. motor I are established, the efficiency of the motor will be ? | |
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100%
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around 99%
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anywhere between 75% and 90%
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less than 50%
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| 10. | At the instant of starting when a D.C. motor is put on supply, it behaves like ? | |
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a highly resistive circuit
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a low resistance circuit
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a capacitive circuit
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none of the above
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