A separately excited dc motor is controlled by varying its armature voltage using a single phase full-converter bridge as shown in figure; the field current is kept constant at the rated value. The motor has an armature resistance of 0.2Ω, and the motor voltage constant is 2.5V (rad/sec).  The motor is driving a mechanical load having a constant torque of 140 Nm. The triggering angle of the converter  is.

The armature current can be assumed to be continuous and ripple free.

(a) Calculate the motor armature current

(b) Evaluate the motor speed in rad/sec

(c) Calculate the RMS value of the fundamental component of the input current to the bridge.