A. it increases the input power con-sumption
B. commutator gets damaged
C. both A. and B.
D. none of the above
Related Mcqs:
- Sparking at the commutator of a D.C. motor may result in____________?
A. damage to commutator segments
B. damage to commutator insulation
C. increased power consumption
D. all of the above - 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 - 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 - 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 - 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 - 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% - 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 - For which of the following applications a D.C. motor is preferred over an A.C. motor ?
A. Low speed operation
B. High speed operation
C. Variable speed operation
D. Fixed speed operation - 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% - 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
