Understanding Power Factor: Maximizing Efficiency and Performance
When evaluating a generator project, you might come across the term “generator power factor” in a spec sheet or in a discussion with your solution provider. Power factor is typically expressed as a decimal or percentage and represents the lowest ratio of real power to reactive power that a generator system can operate while still maintaining its full power rating. In an ideal situation, all the power drawn from a system would be used for useful work. However, due to the changing electric and magnetic fields (capacitance and inductance) associated with each piece of equipment that you connect to your generator, a system’s typical power factor is usually less than 100% (or less than 1), meaning not all the power that the generator produces does real work in the equipment you connect.
Power factor can be understood through the relationships between different variables. It refers to the relationship between real power, reactive power, and apparent power. Real power, also known as working power, is the actual amount of power the generator produces to power a given load, measured in watts (W). Reactive power represents the unusable power produced by the generator, measured in Volt-Amps-Reactive (VAR) that is lost or wasted in the equipment the generator is powering and a characteristic of how much inductance and/or capacitance a given load has. Apparent power, or total power, is the sum of real power and reactive power, generated by the circuit’s voltage and current and measured in Volt-Amps (VA).
Although the generator supplies the power, it is the connected loads – the devices being powered – that determine a system’s power factor. It is important that your solution providers and partners understand your specific loads to ensure that your generator system is properly sized for your system’s power factor. An industry-standard generator power factor rating is 0.8 or 80%, which means most commercial and industrial generators can provide their nameplate rating (Watts) down to a power factor of 0.8 or 80%. Below that rated value a generator will derate and eventually trip offline as voltage continues to drop. Understanding your individual loads and the characteristics of your unique electrical system is an essential part of any project involving generator equipment and something the right partners will be happy to help work through before a system is designed and installed.
