A series motor, having an armature resistance of 0.1 Q and a field resistance of 0.15 Q, takes 48 A at 230V and 720 rpm. The total core and friction losses are 650 W. Neglecting stray-load and brush-contact losses, calculate (a) the developed torque, (b) output power at the shaft, and (c) the motor efficiency.

Fig: 1