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EEE :: D.C. Motors

  1. In case of conductively compensated D.C. series motors, the compensating winding is provided

  2. A.

     As separately wound unit

    B.

     In parallel with armature winding

    C.

     In series with armature winding

    D.

     In parallel with field winding


  3. If a D.C. motor is to be selected for conveyors, which rioter would be preferred?

  4. A.

     Series motor

    B.

     Shunt motor

    C.

     Differentially compound motor

    D.

     Cumulative compound motor


  5. Torque developed by a D.C. motor depends upon

  6. A.

     Magnetic field

    B.

     Active length of the conductor

    C.

     Current flow through the conductors

    D.

     All above factors


  7. The starting resistance of a D.C. motor is generally

  8. A.

     Low

    B.

     Around 500 Q

    C.

     1000 Q

    D.

     Infinitely large


  9. D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value for short duration. We will select the

  10. A.

     Series motor

    B.

     Shunt motor

    C.

     Compound motor

    D.

     Any of the above


  11. As the load is increased the speed of D.C. shunt motor will

  12. A.

     Reduce slightly

    B.

     Increase slightly

    C.

     Increase proportionately

    D.

     Remains unchanged


  13. The total losses in a well designed D.C. generator of 10 kW will be nearly

  14. A.

     100 W

    B.

     500 W

    C.

     1000 W

    D.

     1500 W


  15. Sparking, is discouraged in a D.C. motor because

  16. A.

     It increases the input power consumption

    B.

     Commutator gets damaged

    C.

     Both (A) and (B)

    D.

     None of the above


  17. Why are the D.C. motors preferred for traction applications?

  18. A.

     Torque and speed are inversely proportional to armature current

    B.

     Torque is proportional to armature current

    C.

     Torque is proportional to square root of armature current

    D.

     The speed is inversely proportional to the torque and the torque is proportional to square of armature current


  19. D.C. generators are installed near the load centers to reduce

  20. A.

     Iron losses

    B.

     Line losses

    C.

     Sparking

    D.

     Corona losses