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
Which D.C. motor is preferred for elevators ?
(A) Shunt motor
(B) Series motor
(C) Differential compound motor
(D) Cumulative compound motor
Differentially compound D.C. motors can find applications requiring___________?
(A) high starting torque
(B) low starting torque
(C) variable speed
(D) frequent on-off cycles
Which D.C. motor will be preferred for machine tools ?
(A) Series motor
(B) Shunt motor
(C) Cumulative compound motor
(D) Differential compound motor
These days D.C. motors are widely used in____________?
(A) pumping sets
(B) air compressors
(C) electric traction
(D) machine shops
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
In case of D.C. shunt motors the speed is dependent on back e.m.f. only because____________?
(A) back e.m.f. is equal to armature drop
(B) armature drop is negligible
(C) flux is proportional to armature current
(D) flux is practically constant in D:
What will happen if the back e.m.f. of a D.C. motor vanishes suddenly?
(A) The motor will stop
(B) The motor will continue to run
(C) The armature may burn
(D) The motor will run noisy
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
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