As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent a heavy current from flowing though the armature circuit____________________?

Related Mcqs:

1. 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

2. In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be_____________?

   A. almost negligible
   B. rated full-load current
   C. less than full-load current
   D. more than full-load current

3. The current drawn by the armature of D.C. motor is directly proportional to__________?

   A. the torque required
   B. the speed of the motor
   C. the voltage across the terminals
   D. none of the above

4. If I2 be the armature current, then speed of a D.C. shunt motor is_______________?

   A. independent of Ia
   B. proportional to la
   C. varies as (Ia)
   D. varies as la

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. The armature torque of the D.C. shunt motor is proportional to____________?

   A. field flux only
   B. armature current only
   C. both A. and B.
   D. none of the above

9. If the terminals of armature of D.C. motor are interchanged, this action will offer following kind of braking?

   A. regenerative
   B. plugging
   C. dynamic braking
   D. none of the above
   E. any of the above

10. Armature reaction in dc motor results___________?

    A. decrease in speed
    B. increase in speed
    C. short circuit
    D. open circuit