Armature reaction in dc motor results___________?

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. 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

3. 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

4. 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

5. 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

6. The armature voltage control of D.C. motor provides____________?

   A. constant torque drive
   B. constant voltage drive
   C. constant current drive
   D. none of the above

7. 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____________________?

   A. a resistance is connected in series with armature
   B. a resistance is connected parallel to the armature
   C. armature is temporarily open circuited
   D. a high value resistor is connected across the field winding

8. The armature voltage control of D.C. motor provides_____________?

   A. constant voltage drive
   B. constant current drive
   C. constant torque drive
   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. When the armature of a D.C. motor rotates, e.m.f. induced is___________?

    A. self-induced e.m.f.
    B. mutually induced e.m.f.
    C. back e.m.f
    D. none of the above