A. independent of Ia
B. proportional to la
C. varies as (Ia)
D. varies as la
Related Mcqs:
- 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 - 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 - The speed of a D.C. shunt motor more than its full-load speed can be obtained by_____________?
A. decreasing the field current
B. increasing the field current
C. decreasing the armature current
D. increasing the armature current - 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 - 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 - 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 - The armature torque of the D.C. shunt motor is proportional to____________?
A. field flux only
B. armature current only
C. both A. and B.
D. none of the above - 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 - 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 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
