In three-phase induction motors sometimes copper bars are placed deep in the rotor to
A. Improve starting torque
B. Reduce copper losses
C. Improve efficiency
D. Improve power factor
Answer: Option A
A. Improve starting torque
B. Reduce copper losses
C. Improve efficiency
D. Improve power factor
Answer: Option A
Which is of the following data is required to draw the circle diagram for an induction motor?
A. Block rotor test only
B. No load test only
C. Block rotor test and no-load test
D. Block rotor test, no-load test and stator resistance test
The starting torque of a three phase induction motor can be increased by
A. Increasing slip
B. Increasing current
C. Both (A) and (B)
D. None of the above
Rotor rheostat control method of speed control is used for
A. Squirrel-cage induction motors only
B. Slip ring induction motors only
C. Both (A) and (B)
D. None of the above
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