Why is DC motor wider than AC motor? High speed regulation accuracy? How do you know?
The DC motor has the ability to keep the rated torque from the zero speed to the nominal speed, so it can perform stepless speed regulation from zero speed to rated speed (constant torque).
The speed regulation of DC motor usually depends on changing the voltage at the two ends of the armature. The speed and voltage are basically linear, so the speed regulation accuracy is high. However, due to the brush limit, the DC power is generally not largeThe speed change of an AC motor depends on changing the pole number or changing the frequency, while the mechanical characteristic is related to the rotor resistance, armature current and so on. The ancient and lower precision, to achieve servo control should be introduced into the closed loop control system.
And AC motor plus inverter (AC motor itself can not speed), if the stepless speed regulation, its torque is changed with the speed of the motor changes, generally when less than 30HZ when the operation is unstable. So, DC is wider than AC speed regulation.
