A 1-phase motor with auxiliary winding has mostly a bad starting torque.
If the auxiliary winding is fed with a run capacitor, this capacitor is calculated for the nominal speed.
But to obtain a good starting torque you need a much bigger capacitor and only during a few seconds, when the speed is low.
The centrifugal switch connects a startcapacitor to the auxiliary winding as long as the speed of the motor is too slow.
If the motor is blocked or does not reach that speed the startcapacitor and /or the auxiliary winding may get damaged.
We recommend to use some protection (e.g. thermal, see electric options)
Our motors equipped with switch are noted BS or MC (see products, electrical part)