Q. 41 The separately excited dc motor in the figure below has a rated armature current of 20 A and a rated armature voltage of 150 V. An ideal chopper switching at 5 kHz is used to control the armature voltage. If 
,
neglecting armature reaction, the duty ratio of the chopper to obtain 50% of the rated torque at the rated speed and the rated field current is 
(A) 0.4
(B) 0.5
(C) 0.6
(D) 0.7
Answer:(D)
Explanation:
