Category: Polyphase Induction Motors

A. Ns
B. s.N,
C. (l-s)Ns
D. (Ns-l)s

A. changing supply frequency
B. changing number of poles
C. changing winding resistance
D. reducing supply voltage

A. noload test
B. blocked rotor test
C. stator resistance test
D. all of the above

A. increases the load torque
B. decreases the starting torque
C. increases the starting torque
D. none of the above

A. power factor at starting is high as compared to that while running
B. power factor at starting is low as compared to that while running
C. power factor at starting in the same as that while running

A. 200 Hz
B. 50 Hz
C. 2 Hz
D. 0.2 Hz

A. The slip of the motor will be 5%
B. The rotor will not run
C. The rotor will run at very high speed
D. The torque produced will be very large

A. low horsepower motors
B. variable speed motors
C. high horsepower motors
D. high speed motors

A. pulling the motor directly on line without a starter
B. locking of rotor due to harmonics
C. starting the motor on load which is more than the rated load
D. interchanging two supply phases for quick stopping

A. Squirrel-cage induction motor
B. Slip-ring induction motor
C. Both A. and (b)
D. None of the above