Following motor is used where high starting torque and wide speed range control is required?

Related Mcqs:

1. Which of the following load normally needs starting torque more than the rated torque?

   A. Blowers
   B. Conveyors
   C. Air compressors
   D. Centrifugal pumps

2. The ratio of starting torque to full-load torque is least in case of____________?

   A. series motors
   B. shunt motors
   C. compound motors
   D. none of the above

3. Which of the following application requires high starting torque ?

   A. Lathe machine
   B. Centrifugal pump
   C. Locomotive
   D. Air blower

4. Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of_____________?

   A. D.C. series motor
   B. D.C. shunt motor
   C. induction motor
   D. all of above motors

5. The speed of a D.C. shunt motor is required to be more than full load speed. This is possible by______________?

   A. reducing the field current
   B. decreasing the armature current
   C. increasing the armature current
   D. increasing the excitation current
   E. none of the above methods

6. The speed of a motor falls from 1100 r.p.m. at no-load to 1050 r.p.m. at rated load. The speed regulation of the motor is______________?

   A. 2.36%
   B. 4.76%
   C. 6.77%
   D. 8.84%

7. In a D.C. series motor, if the armature current is reduced by 50%, the torque of the motor will be equal to

   A. 100% of the previous value
   B. 50% of the previous value
   C. 25% of the previous value
   D. 10% of the previous value
   E. none of the above

8. For the same H.P. rating and full load speed, following motor has poor starting torque_____________?

   A. shunt
   B. series
   C. differentially compounded
   D. cumulativelyc’ompounded

9. For starting a D.C. motor a starter is required because___________?

   A. it limits the speed of the motor
   B. it limits the starting current to a safe value
   C. it starts the motor
   D. none of the above

10. Where D.C. motor of H.P. 12 or more requires frequent starting, stopping, reversing and speed control______________?

    A. drum type controller is used
    B. three point starter is used
    C. four point starter is used
    D. all above can be used