What does the term 'Cos φ' refer to in three-phase power formulas?

The term 'Cos φ' refers to the power factor in three-phase power formulas. In electrical engineering, the power factor is a measure of how effectively electrical power is being converted into useful work output. It is the cosine of the phase angle (φ) between the voltage and current in an AC (alternating current) system. A power factor of 1 (or 100%) indicates that all the power is being used effectively for its intended purpose, while a lower power factor indicates that some power is wasted, often as reactive power, which does not do any useful work.

Understanding the power factor is crucial for improving efficiency in electrical systems, as it can directly influence energy costs and the capability of the electrical infrastructure. A high power factor is desirable because it indicates less wasted energy in the system, which is important for both operational efficiency and compliance with regulations regarding energy consumption.