A. residual magnetism of the generator
B. core losses of motor
C. mechanical losses of motor and generator together
D. all of the above
Related Mcqs:
- Speed control by Ward Leonard method gives uniform speed variation_____________?
A. in one direction
B. in both directions
C. below normal speed only
D. above normal speed only - Ward Leonard method of speed control is basically a______________?
A. field control method
B. armature controlled method
C. field diverter
D. frequency control method - Ward-Leonard control is basically a____________?
A. voltage control method
B. field divertor method
C. field control method
D. armature resistance control method - The main disadvantage of the Ward-Leonard control method is______________?
A. high initial cost
B. high maintenance cost
C. low efficiency at Hght loads
D. all of the above - 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 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% - 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 - No-load speed of which of the following motor will be highest ?
A. Shunt motor
B. Series motor
C. Cumulative compound motor
D. Differentiate compound motor - Usually wide and sensitive speed control is desired in case of____________?
A. centrifugal pumps
B. elevators
C. steel rolling mills
D. colliery winders - With the increase in temperature, the speed of DC series motor______________?
A. decreases
B. increases
C. remain same
D. none of the above
