21. |
In an induction motor if the air gap is increased than which of the following statement is correct
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Answer:
Option (a) |
22. |
what is the ratio of rotor input power to rotor copper loss in an induction motor?
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Answer:
Option (c) |
23. |
If an induction machine is run at above the synchronous speed it acts as
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Answer:
Option (c) |
24. |
Induction motors have the advantage of
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Answer:
Option (d) |
25. |
An 8 pole, three phase induction motor is supplied from 50 Hz, a.c. supply. On full load, the frequency of induced EMF in the rotor is 2 Hz. Then the full load slip and the corresponding speed.
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Answer:
Option (b) |
26. |
A 4 pole, 3 phase, 50 Hz induction motor runs at a speed of 1470 r.p.m. speed. Then the frequency of the induced e.m.f. in the rotor under this condition
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Answer:
Option (a) |
27. |
The direction of rotation of 3-Φ induction motor is clockwise when it is supplied with the 3-Φ sinusoidal voltage having phase sequence of A-B-C. For counterclockwise rotation, the phase sequence of the power supply should be
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Answer:
Option (b) |
28. |
The rotor winding of a 3-phase wound rotor induction motor is generally _____________ connected.
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Answer:
Option (b) |
29. |
An eight-pole wound rotor induction motor operating on 60 Hz supply is driven at 1800 rpm by a prime mover in the opposite direction of revolving magnetic field. The frequency of rotor current is
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Answer:
Option (b) |
30. |
The torque characteristic of a 3-phase induction motor is similar to that of
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Answer:
Option (b) |