The speed of a D.C. motor can be varied by varying
A)field current
B)applied voltage
C)resistance in series with armature
D)any of the above

Question

Quizplus · Accepted Answer

The speed of a DC motor can be varied by varying the field current, which changes the magnetic field strength; by varying the applied voltage, which changes the armature current; or by varying the resistance in series with the armature, which affects the current through the motor. Therefore, all the given options are correct ways to vary the speed of a DC motor.

The Speed of a D