| 1. | Which of the following statements regarding a reluctance motor is incorrect ? | |
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It cannot be reversed, ordinarily
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It requires no D.C. field excitation for its operation
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It is nothing else but a single-phase, salient pole synchronous-induction motor
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Its squirrel cage-rotor is of unsymmetrical magnetic construction in order to vary reluctance path between stator and rotor
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Report Question| 2. | Hysteresis motor is particularly useful for high-quality record players and tape-recorders because ? | |
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it revolves synchronously
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it is not subject to any magnetic or mechanical vibrations
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it can be easily manufactured in extremely small sizes of upto 1 W output
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it develops hysteresis torque which is extremely steady both in amplitude and phase
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| 3. | In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will ? | |
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become unstable
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draw excessive armature current and may burn out
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fall out of synchronism and come to stand still
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Run as induction motor
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| 4. | Which of the following motors has highest starting torque ? | |
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Repulsion motor
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Shaped pole motor
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Capacitor-start motor
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Split-phase motor
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| 5. | The repulsion-start induction-run motor is used because of ? | |
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good power factor
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high efficiency
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minimum cost
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High starting torque
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| 6. | The speed of a universal motor is generally reduced by using ? | |
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gear trains
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V-belts
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brakes
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chains
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| 7. | In a hysteresis motor, the rotor must have ? | |
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retentivity
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resistivity
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susceptibility
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none of the above
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| 8. | The speed control of universal motor used for sewing machines is by ? | |
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friction
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varying the resistance
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tapping the field
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centrifugal mechanism
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| 9. | In repulsion motor, maximum torque is developed when ? | |
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Brush axis is at 45º electrical to the field axis
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brush axis coincides with the field axis
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brush axis is at 90º electrical to the field axis
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none of the above
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| 10. | Which of the following single-phase motors is suitable for timing and control purposes ? | |
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Reluctance motor
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Series motor
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Repulsion motor
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Universal motor
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