Regenerative method of braking is based on that___________?
A. back e.m.f. is less than the applied voltage
B. back e.m.f. is equal to the applied voltage
C. back e.m.f. of rotor is more than the applied voltage
D. none of the above
A direct on line starter is used: for starting motors___________?
A. up to 5 H.P
B. up to 10 H.P
C. up to 15 H.P
D. up to 20 H.P
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
Which of the following motors one will choose to drive the rotary compressor ?
A. D.C. shunt motor
B. D.C. series motor
C. Universal motor
D. Synchronous motor
When the armature of a D.C. motor rotates, e.m.f. induced is___________?
A. self-induced e.m.f.
B. mutually induced e.m.f.
C. back e.m.f
D. none of the above
Why are the D.C. motors preferred for traction applications ?
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
Which method of braking is generally used in elevators ?
A. Plugging
B. Regenerative braking
C. Rheostatic braking
D. None of the above