What is the function of a capacitor in a motor circuit?

The function of a capacitor in a motor circuit is primarily to provide a phase shift for starting and enhancing efficiency. Motors often require a phase shift to start effectively, especially single-phase motors. When a capacitor is used, it creates a leading current that helps to establish a rotating magnetic field in the stator. This action is crucial as it allows the motor to overcome inertia and start running.

Moreover, once the motor is running, the capacitor can continue to assist with improving the overall efficiency by helping in the phase correction, reducing losses, and allowing the motor to operate closer to its optimal performance level. The capacitor essentially improves the motor's power factor, which is an important aspect of electrical systems.

In contrast, while capacitors may momentarily store electrical energy, they do not store current in the way a battery does. Their task is not to resist current flow, which is more associated with resistors, or to decrease voltage, which can be done by transformers or other devices. Therefore, the role of the capacitor is distinct and crucial in motor applications for efficient operation.