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

Related Mcqs:

1. 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

2. In a star-delta starter of an induction motor___________?

   A. resistance is inserted in the stator
   B. reduced voltage is applied to the stator
   C. resistance is inserted in the rotor
   D. applied voltage perl stator phase is 57.7% of the line voltage

3. The starting torque of a squirrel-cage induction motor is___________?

   A. low
   B. negligible
   C. same as full-load torque
   D. slightly more than full-load torque

4. 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

5. 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

6. 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

7. DOL starting of induction motors is usually restricted to_____________?

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

8. Reduced voltage starter can be used with_____________?

   A. slip ring motor only but not with squirrel cage induction motor
   B. squirrel cage induction motor only but not with slip ring motor
   C. squirrel cage as well as slip ring induction motor
   D. none of the above

9. 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

10. 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