A single- phase full- wave rectifier is used to control the
speed of a 5- hp, 110- V, 1200- rpm, separately- excited dc motor.
The converter is connected to a single- phase, 120- V, 60- Hz
supply. The motor has a winding resistance of 0.4ohms and an
inductance of 5 mH, and a voltage constant K=0.09V/rpm.
a. During the motoring operation, the motor runs at 1000 rpm and
receives an armature current of 30 A. Determine the corresponding
firing angle...