What effect does a failing capacitor have on a single-phase motor?

A failing capacitor in a single-phase motor can significantly affect the motor's operation, particularly its ability to start. The capacitor is crucial for creating a phase shift in the electrical current which is essential for generating the magnetic field required to initiate the motor's rotation. When the capacitor is functioning properly, it enables the motor to develop enough torque to start turning.

If the capacitor is failing or has failed, it may not provide the necessary phase shift or sufficient current to the start winding of the motor. This can result in the motor either failing to start altogether or stalling shortly after trying to start. In some cases, the motor may hum or make other sounds indicating it is attempting to operate without successfully getting up to speed.

This issue does not correlate with aspects like efficiency or power factor; a failing capacitor generally leads to poorer performance and can result in increased wear and potential damage to the motor over time. Hence, the correct understanding of the impact of a failed capacitor highlights its critical role in the starting mechanism of a single-phase motor.