Power factor (cos φ )
What is power factor cos fi?
What can the power factor cos fi be?
The importance of the cos fi power factor in the context of LED lighting

Power factor (cos φ )

The power factor - cos φ - is a measure of the use of electrical energy (active power) by a device relative to the energy supplied to it (apparent power). If any component of the circuit has this coefficient less than one, then we start dealing with energy that has been consumed but not used (reactive power), which is converted into adverse phenomena, such as overheating of wires, etc. For the domestic user, the power factor is irrelevant, since he pays anyway for the energy actually used, i.e. active power. But industrial consumers already have to prevent reactive power or compensate it accordingly.

Where:

P - active power, S - apparent (combined) power

What is power factor cos fi?

To understand what the cos phi power factor indicates, it is worth defining the concept first. The cos phi power factor is a measure of the use of electrical energy (active power) by a device relative to the energy supplied to it (apparent power). When a given circuit element has a cos phi factor of less than 1, it means that in its case there is a situation in which energy is consumed but not used (reactive power). This unused, consumed energy is converted into various types of undesirable phenomena. An example of such a phenomenon is overheating of wires. It is usually assumed that the cos phi power factor is important information primarily for industrial recipients, who should strive to effectively prevent the occurrence of reactive power or to compensate for it appropriately.

What does the cos phi formula look like? The cos phi power factor can be expressed as the ratio of P (active power) to S (apparent power, also known as complex power).

What can the power factor cos fi be?

The power factor cos phi can have values from 0 to 1. When it is 1, it means that all the energy supplied to the device was used to perform useful work. In such a situation, we are not dealing with reactive power. When the power factor cos phi is less than 1, some energy is lost and reactive power occurs.

The higher the power factor cos phi, the more efficient the device is in terms of using the energy supplied to it. This is particularly important when a large number of devices are connected to the electrical network. If the devices are characterized by a low power factor cos phi, significant energy losses are recorded, which is associated with higher costs and often also with network overload.

The importance of the cos fi power factor in the context of LED lighting

The parameter cos fi is an important criterion to consider when choosing lighting. As mentioned earlier, the higher the cos fi power factor, the better, as it indicates a higher level of energy efficiency of a given device. We are dealing with a similar situation in the case of lighting fixtures - a high power factor is one of the aspects worth considering when making a purchase decision.

At this point, it is worth recalling the requirements for LED lighting, which are included in COMMISSION REGULATION (EU) No 1194/2012 of 12 December 2012 implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to ecodesign requirements for directional lamps, light-emitting diode lamps and related equipment. The cited regulation indicates that in the case of non-directional and directional LED lamps:

for P ≤ 2 W (where P is active power), there is no requirement to specify the lamp power factor for lamps with built-in control gear (cos phi);
for P greater than 2 W but less than or equal to 2 W, the cos phi should be greater than 0.4;
for P greater than 5 W but less than or equal to 25 W, the cos phi should be greater than 0.5;
for P greater than 25 W, the cos phi should be greater than 0.9.

As a renowned Polish LED lighting manufacturer, Lena Lighting, we offer a variety of LED lighting fixtures characterized not only by a high cos phi value, but also by many other advantages, such as high luminous efficiency, reliability and a modern, elegant design. We encourage you to familiarize yourself with our products.

FAQ

What is power factor cos φ?

Power factor cos φ is a measure of the efficiency of electrical energy use, which shows the ratio of active power to apparent power. It determines how effectively a device converts supplied energy into useful work.

What are the power factor values?

Power factor can range from 0 to 1: