What is the primary purpose of a power factor correction capacitor?

The primary purpose of a power factor correction capacitor is to compensate for reactive power in the electrical system. In alternating current (AC) systems, especially those with inductive loads such as motors and transformers, the current can lag behind the voltage, leading to a power factor less than 1. This situation indicates that not all the power supplied is being utilized effectively, as some of it is reactive power that oscillates between the source and the load without being used to perform useful work.

By adding capacitors to the circuit, they provide leading reactive power which helps to neutralize the lagging reactive power caused by inductive loads. This compensation reduces the total current flowing in the system, improves the power factor, and ensures that the electrical system operates more efficiently. A better power factor means that less current is needed for the same amount of useful power, which can translate to lower electricity costs and reduced strain on the electrical infrastructure.

This concept is crucial for maintaining system efficiency and stability while reducing losses in power transmission.