In case-the conditions for maximum power for a D.C. motor are established, the efficiency of the motor will be______________?

Related Mcqs:

1. 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

2. The condition for maximum power in case of D.C. motor is______________?

   A. back e.m.f. = 2 x supply voltage
   B. back e.m.f. = | x supply voltage
   C. supply voltage = | x back e.m.f
   D. supply voltage = back e.m.f

3. 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

4. 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

5. 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

6. The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is______________?

   A. 4.0
   B. 2.0
   C. 1.0
   D. 0.5

7. If the field of a D.C. shunt motor gets opened while motor is running______________?

   A. the speed of motor will be reduced %
   B. the armature current will reduce
   C. the motor will attain dangerously high speed 1
   D. the motor will continue to nuvat constant speed

8. 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

9. 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%

10. 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