What component is responsible for disconnecting the start winding of a single phase motor once it reaches full speed?

The component responsible for disconnecting the start winding of a single-phase motor once it reaches full speed is the centrifugal switch. This device is activated by the centrifugal force generated when the motor reaches a predetermined speed. At that point, the switch opens and effectively disconnects the start winding from the power supply. This action is crucial because the start winding is only needed for starting the motor; once the motor is at full speed, keeping the start winding energized would lead to overheating and eventual damage due to continuous operation at high power.

In contrast, the start relay is typically used in some motor designs but relies on a different operational principle, such as electrical or mechanical signals rather than centrifugal force. A thermostat monitors temperature to protect against overheating but does not directly control the disconnection of the start winding. The overload protector is designed to disrupt the circuit in case of excessive current, providing protection but not specifically handling the disconnection of the start winding based on speed.