How does the start winding in a split-phase motor differ from the run winding?

In a split-phase motor, the start winding plays a crucial role in initiating the motor's operation. The start winding is designed specifically to create a phase shift that allows the motor to start turning. Once the motor reaches a certain speed, typically around 70-80% of its full speed, a centrifugal switch or a relay disconnects the start winding from the circuit.

This disconnection is essential because the start winding is generally not designed for continuous operation; it has higher resistance and is meant to provide the necessary starting torque. Keeping it connected at higher speeds could lead to overheating or damage, as it is not built to handle prolonged use. Therefore, the correct answer highlights that the start winding is disconnected at higher speeds to protect the motor and ensure efficient operation.