In a D.C. generator, the iron losses mainly take place in___________/

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

Which of the following load normally needs starting torque more than the rated torque?

A. Blowers
B. Conveyors
C. Air compressors
D. Centrifugal pumps

Which of the following steps is likely to result in reduction of hysteresis loss in a D.C. generator ?

A. Providing laminations in armature core
B. Providing laminations in stator
C. Using non-magnetic material for frame
D. Using material of low hysteresis co-efficient for armature core material

In case-the conditions for maximum power for a D.C. motor are established, the efficiency of the motor will be______________?

A. 100%
B. around 90%
C. anywhere between 75% and 90%
D. less than 50%

If the terminals of armature of D.C. motor are interchanged, this action will offer following kind of braking?

A. regenerative
B. plugging
C. dynamic braking
D. none of the above
E. any of the above

Which of the following motors is usually used in house-hold refrigerators ?

A. D.C. shunt motor
B. D.C. series motor
C. Single phase induction motor (split phase start or induction run motor)
D. Reluctance motor
E. Synchronous motor