What does basically determine the speed of a dc motor?
If a DC motor has a constant field current, the speed is basically determined by the armature voltage.
In general, the steady state operating speed of any motor is at the intersection of the motor’s torque vs. speed characteristic curve and the torque vs. speed characteristic curve of the connected load. The basic shape of a DC motor’s speed-torque curve is determined by the field connection; series, shunt, compound or separately excited. The armature voltage determines the position of the torque-speed curve with respect to the speed axis.
