Slip of an induction motor is negative when_____________?

Related Mcqs:

1. Slip ring motor is preferred over squirrel cage induction motor where___________?

   A. high starting torque is required
   B. load torque is heavy
   C. heavy pull out torque is required
   D. all of the above

2. In an induction motor, no-load the slip is generally____________?

   A. less than 1%
   B. 1.5%
   C. 2%
   D. 4%

3. A 3-phase 440 V, 50 Hz induction motor has 4% slip. The frequency of rotor e.m.f. will be____________?

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

4. The number of slip rings on a squirrel cage induction motor is usually____________?

   A. two
   B. three
   C. four
   D. none

5. In Ns is the synchronous speed and s the slip, then actual running speed of an induction motor will be___________?

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

6. The shape of the torque/slip curve of induction motor is__________?

   A. parabola
   B. hyperbola
   C. rectangular parabola
   D. straigth line

7. The stating torque of the slip ring induction motor can be increased by adding__________?

   A. external inductance to the rotor
   B. external resistance to the rotor
   C. external capacitance to the rotor
   D. both resistance and inductance to rotor

8. A 500 kW, 3-phase, 440 volts, 50 Hz, A.C. induction motor has a speed of 960 r.p.m. on full load. The machine has 6 poles. The slip of the machine will be__________?

   A. 0.01
   B. 0.02
   C. 0.03
   D. 0.04

9. In induction motor, percentage slip depends on__________?

   A. supply frequency
   B. supply voltage
   C. copper losses in motor
   D. none of the above

10. In medium sized induction motors, the slip is generally around___________?

    A. 0.04%
    B. 0.4%
    C. 4%
    D. 14%