If an induction motor with certain ratio of rotor to stator slots, runs at 1/7 of the normal speed, the phenomenon will be termed as____________?

Related Mcqs:

1. In an induction motor the relationship between stator slots and rotor slots is that_____________?

   A. stator slots are equal to rotor slots
   B. stator slots are exact multiple of rotor slots
   C. stator slots are not exact multiple of rotor slots
   D. none of the above

2. What will happen if the relative speed between the rotating flux of stator and rotor of the induction motor is zero ?

   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

3. In the squirrel-cage induction motor the rotor slots are usually given slight skew__________?

   A. to reduce the magnetic hum and locking tendency of the rotor
   B. to increase the tensile strength of the rotor bars
   C. to ensure easy fabrication
   D. none of the above

4. In squirrel cage induction motors, the rotor slots are usually given slight skew in order to__________?

   A. reduce windage losses
   B. reduce eddy currents
   C. reduce accumulation of dirt and dust
   D. reduce magnetic hum

5. If a 3-phase supply is given to the stator and rotor is short circuited rotor will move___________?

   A. in the opposite direction as the direction of the rotating field
   B. in the same direction as the direction of the field
   C. in any direction depending upon phase squence of supply

6. The rotor of an induction motor runs at__________?

   A. synchronous speed
   B. below synchronous speed
   C. above synchronous speed
   D. any of the above

7. A 3-phase induction motor stator delta connected, is carrying full load and one of its fuses blows out. Then the motor_______________?

   A. will continue running burning its one phase
   B. will continue running burning its two phases
   C. will stop and carry heavy current causing permanent damage to its winding
   D. will continue running without any harm to the winding

8. Temperature of the stator winding of a three phase induction motor is obtained by___________?

   A. resistance rise method
   B. thermometer method
   C. embedded temperature method
   D. all above methods

9. 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

10. The injected e.m.f. in the rotor of induction motor must have__________?

    A. zero frequency
    B. the same frequency as the slip frequency
    C. the same phase as the rotor e.m.f.
    D. high value for the satisfactory speed control