In case of 3-phase induction motors, plugging means__________?

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

In a three-phase induction motor_______________?

A. Iron losses in stator will be negligible as compared to that in rotor
B. Iron losses in motor will be neg¬ligible as compared to that in rotor
C. Iron losses in stator will be less than that in rotor
D. Iron losses in stator will be more than that in rotor

Short-circuit test on an induction motor cannot be used to determine___________?

A. Windage losses
B. Copper losses
C. Transformation ratio
D. Power scale of circle diagram

The starting torque of a 3-phase squirrel cage induction motor is____________?

A. Twice the full load torque
B. 1.5 times the full load torque
C. Equal to full load torque

A 3-phase slip ring motor has____________?

A. Double cage rotor
B. Wound rotor
C. Short-circuited rotor
D. Any of the above

5 H.P., 50-Hz, 3-phase, 440 V, induction motors are available for the following r.p.m. Which motor will be the costliest ?

A. 730 r.p.m.
B. 960 r.p.m.
C. 1440 r.p.m.
D. 2880 r.p.m.

A pump induction motor is switched on to a supply 30% lower than its rated voltage. The pump runs. What will eventually happen ? It will____________?

A. Stall after sometime
B. Stall immediately
C. Continue to run at lower speed without damage
D. Get heated and subsequently get damaged

Which type of bearing is provided in small induction motors to support the rotor shaft ?

A. Ball bearings
B. Cast iron bearings
C. Bush bearings
D. None of the above

The speed characteristics of an induction motor closely resemble the speedload characteristics of which of the following machines?

A. D.c. series motor
B. D.c. shunt motor
C. Universal motor
D. None of the above

It is advisable to avoid line starting of induction motor and use starter because____________?

A. It will run in reverse direction
B. It will pick up very high speed and may go out of step
C. Motor takes five to seven times its full load current
D. Starting torque is very high