The PSC motor is available as a variable-speed motor.
Since the PSC motor does not require a centrifugal switch, it does not
have an end plate or access plate. Instead, all the leads that the motor
has provided are brought out of the motor together near the end plate.
These leads are generally color coded to identify their speed. Fig. 1b
shows a diagram for a multispeed PSC motor. The color leads are connected
at various points along the run winding coil. If power is applied at
the very end of the run winding, all the poles of the run winding are
used, and the motor will operate at its lowest speed. If power is connected
at the terminal marked high speed, only one of the poles is used, and the motor will operate at its highest speed. Note that the motor will
lose torque as its speed is increased because fewer windings are used
to gain the extra speed.
Above: Fig. 1