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

Related Mcqs:

1. 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%

2. 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

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

   A. Single phase capacitor start
   B. Induction motor
   C. Synchronous motor
   D. D.C. motor
   E. None of the above

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

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

5. By looking at which part of the motor, it can be easily confirmed that a particular motor is D.C. motor?

   A. Frame
   B. Shaft
   C. Commutator
   D. Stator

6. Flywheel is used with D.C. compound motor to reduce the peak demand by the motor, compound motor will have to be_____________?

   A. level compounded
   B. under compounded
   C. cumulatively compounded
   D. differentially compounded

7. One D.C. motor drives another D.C. motor. The second D.C. motor when excited and driven_______________?

   A. runs as a generator
   B. does not run as a generator
   C. also runs as a motor comes to stop after sometime

8. If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will_________?

   A. increase
   B. decrease
   C. remain same
   D. become zero

9. The speed of a D.C. shunt motor more than its full-load speed can be obtained by_____________?

   A. decreasing the field current
   B. increasing the field current
   C. decreasing the armature current
   D. increasing the armature current

10. 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