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

Related Mcqs:

1. If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens__________?

   A. nothing will happen to the motor
   B. this will make armature to take heavy current, possibly burning it
   C. this will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses D. motor will run at very slow speed

2. If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens____________?

   A. this will make armature to take heavy current, possibly burning it
   B. this will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses
   C. nothing will happen to motor
   D. motor will come to stop

3. 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

4. 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

5. 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

6. In a D.C. shunt motor, speed is______________?

   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

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

   A. 100%
   B. around 90%
   C. anywhere between 75% and 90%
   D. less than 50%

8. 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

9. 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

10. 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