How does a power factor correction capacitor function?

A power factor correction capacitor functions by supplying reactive power to an electrical circuit, which helps to improve the overall system efficiency. In alternating current (AC) systems, power factor is a measure of how effectively electrical power is being converted into useful work output. When the power factor is low, it indicates that a significant amount of reactive power is present, which does not do useful work but contributes to the total power flow in the circuit.

The capacitor provides reactive power by charging and discharging in sync with the AC waveform, effectively countering the inductive reactance from motors and other inductive loads. This action helps to reduce the amount of reactive power that must be supplied by the utility, which in turn can lead to lower energy costs and improved capacity of the electrical system.

This process can lead to a higher power factor, as it minimizes the phase difference between voltage and current in the circuit. Consequently, it allows the system to operate more efficiently, as more of the total current is used for productive work rather than being wasted due to reactive power.