Speed control
To provide tight speed and torque control, a feedback device, typically an encoder or
resolver, must be added to the motor. Then a vector control can be used to power the spindle
motor.
With vector control, tighter speed regulation approaching 0.01% of set speed can be
attained. Vector controls and high-performance spindle motors, Figure 4, have a constant power
range of about 3.5 times base speed and controllable speed ranges from zero speed to about
five times base speed.