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EEE :: D.C. Motors

  1. If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will

  2. A.

     Increase

    B.

     Decrease

    C.

     Remain same

    D.

     Become zero


  3. In a differentially compounded D.C. motor, if shunt field suddenly opens

  4. A.

     The motor will first stop and then run in opposite direction as series motor

    B.

     The motor will work as series motor and run at slow speed in the same direction

    C.

     The motor will work as series motor and run at high speed in the same direction

    D.

     The motor will not work and come to stop


  5. Speed control by Ward Leonard method gives uniform speed variation

  6. A.

     In one direction

    B.

     In both directions

    C.

     Below normal speed only

    D.

     Above normal speed only


  7. For which types of D.C. motor, dynamic braking is generally used?

  8. A.

     Shunt motors

    B.

     Series motors

    C.

     Compound motors

    D.

     All of the above


  9. Which D.C. motor will be suitable along with flywheel for intermittent light and heavy loads?

  10. A.

     Series motor

    B.

     Shunt motor

    C.

     Cumulatively compounded motor

    D.

     Differentially compounded motor


  11. The type of D.C. motor used for shears and punches is

  12. A.

     Shunt motor

    B.

     Series motor

    C.

     Differential computed D.C. motor

    D.

     Cumulative compound D.C. motor


  13. Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of

  14. A.

     D.C. series motor

    B.

     D.C. shunt motor

    C.

     Induction motor

    D.

     All of above motors


  15. The purpose of retardation test on D.C. shunt machines is to find out

  16. A.

     Stray losses

    B.

     Eddy current losses

    C.

     Field copper losses

    D.

     Windage losses


  17. In a D.C. shunt motor, speed is

  18. A.

     Independent of armature current

    B.

     Directly proportional to the armature current

    C.

     Proportional to the square of the current

    D.

     Inversely proportional to the armature current


  19. To get the speed of D.C, motor below the normal without wastage of electrical energy is used.

  20. A.

     Ward Leonard control

    B.

     Rheostat control

    C.

     Any of the above method

    D.

     None of the above method