Figure shows the circuit schematic of a chopper driven, separately excited d.c. motor. The single-pole double-throw switch operates with a switching period  is 0.2. The motor may be assumed lossless, with an armature inductance of 10 mH. The motor draws an average current of 20A at a constant back emf of 80V, under steady state.

(a) Sketch and label the voltage waveform  of the chopper for one switching period

(b) Sketch and label the motor current  for one switching period.

(c) Evaluate the peak-to-peak current ripple of the motor.