Utilization of Electrical Energy past question

A single phase 220V, 50Hz supply feeds a separately excited dc motor through two single phase semi converters, one for the field and another for armature. The firing angle of the field semi converters is zero, the field resistance is 250 Ω and the armature resistance is 0.2 Ω. The load torque is 150 Nm at 1500 rpm. The voltage constant is 0.8 V/A rad/s and torque constant is 0.8 Nm/A². Assuming armature and field current to be continuous and neglecting losses, determine: (i) Field current. (ii) Firing of the converter in the armature circuit. (iii) Power factor of the converter of the armature circuit.