In Ward-Leonard control the lower limit of speed is imposed by________?
A. residual magnetism of the generator
B. core losses of motor
C. mechanical losses of motor and generator together
D. all of the above
The speed of a D.C. shunt motor is required to be more than full load speed. This is possible by______________?
A. reducing the field current
B. decreasing the armature current
C. increasing the armature current
D. increasing the excitation current
E. none of the above methods
D.C. shunt motors are used for driving____________?
A. trains
B. cranes
C. hoists
D. machine tools
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
For the same H.P. rating and full load speed, following motor has poor starting torque_____________?
A. shunt
B. series
C. differentially compounded
D. cumulativelyc’ompounded
Which of the following motors is most suitable for signalling devices and many kinds of timers ?
A. D.C. shunt motor
B. D.C. series motor
C. Induction motor
D. Reluctance motor
In a DC motor the inter-pole winding is connected in________________?
A. series with field winding
B. series speed armature winding
C. parallel big field winding
D. parallel with armature winding