Utilization of Electrical Energy past question

A single phase, 220 V, 50 Hz supply feeds a separately excited dc motor through two single phase semi-converters, one for the field and another for armature. The firing angle for the field semi-converter is zero. The field resistance is 250 Ω and armature resistance is 0.2 Ω. The load torque is 50 N-m at 1000 rpm. The voltage constant is 0.8 V/A-rad/s and the torque constant is 0.8 N/A². Assuming the armature and field currents to be continuous and neglecting losses, Determine: (i) Field current. (ii) Firing angle of the converter in the armature circuit. (iii) Power factor of the converter of armature.