The following two DC motors are to be compared for certain application:
Motor A: 250 V Shunt motor with 0.2 ohm armature resistance, 125 ohm field resistance,and has a full load operation with 50 armature Amps at 1000 rpm.
Motor B: 250 V Series motor with 0.2 ohm armature resistance, 0.1 ohm field resistance, and has a full load operation with 50 armature Amps at 1000 rpm
Required:
a. While running at full load, what will be the reduction in speed if the load torque is increased by
b. While running at full load, what will be the change in torque if the speed drops by 20%?
c. The added armature starting resistance to start the motor at 200% Of its rated armature current, and what is the corresponding starting torque?
d. What is the starting resistance cut and the motor speed, when the armature current becomes in order to bring the armature current back to the level to continue with its Starting?