What statement is true concerning speed control of a shunt wound DC motor?

Correct Answer: Option C — For armature rheostat control, the greater the resistance the lower the motor speed. For field rheostat control, the greater the resistance the higher the motor speed.

Adding armature circuit resistance drops terminal voltage, reducing motor speed. Conversely, increasing field rheostat resistance weakens field flux, requiring higher armature speed to generate necessary counter-EMF, thereby increasing motor operational speed in accordance with IEEE 45 principles.