Understanding Power Factor and How It Can Save You Money

Power factor in ac unit

If you aren’t an electrician or engineer, you may have never encountered the term “power factor.” Even if you don’t know what it means, power factor exists in electrical systems. Thus, to maximize energy consumption, understanding the basics of the power factor is essential.

The power factor (PF) refers to the energy efficiency of a system. Professionals measure the PF using percentages. The lower the percentage, the less efficient the PF of a system.

Today, we will define the power factor in simple terms and describe how this knowledge can benefit you.

What Is Power Factor?

Power factor describes the ratio of “working power” to “apparent power.” Working power describes the amount of electricity delivered and cycled through a circuit, while apparent power refers to how much power is necessary to run machinery, equipment, lights, etc.

If excess working power exists in the circuit, it becomes wasted energy, as the system does not need it. Thus, the amount of working power delivered to the machinery indicates the “true power” of that system. This calculation indicates whether the system is energy-efficient or inefficient.

To measure working power, experts use kW (kilowatts). To measure apparent power, kVA (kilovolt amperes) is standard.

Energy-efficient systems should have a PF ratio of over 95%. However, power factors depend on technology and the innovation of a type of machinery. For example, generators tend to have a power factor between 80% and 95%.

How To Calculate the True Power Production of a System

Air conditioning unit being checked

The formula to calculate a power factor is PF = kW / kVA. Thus, you divide the working power by the apparent power. This formula applies to AC (alternating current) circuits.

AC circuits use two types of power: real power and reactive power. Real power is what the system needs to run, while reactive power causes the actual components of the machinery to turn, move, etc.

Electric currents create magnetic fields around wires as they flow through the AC circuit. These magnetic fields become stronger with more powerful currents. In an AC circuit, there are “load currents.”

Working power has a voltage, while apparent power has a load current. Scientifically speaking, the voltage and load current both appear as waves. To put it simply, the PF measures the distance between these two waves, aka the phase shift.

Professionals use two categories to describe the efficiency of the power factor known as “leading” and “lagging.”

Leading Power Factor

A leading power factor means that the load current leads the supply voltage. To correct a leading power factor, which indicates that the load current is capacitive, you must apply the opposite type of load. Thus, you must add an inductive load.

Examples of machinery that uses an inductive load include motors, generators, and transformers.

Lagging Power Factor

A lagging power factor represents the opposite of a leading one, indicating that the load current lags behind the supply voltage. Likewise, you must also apply the opposite type of load. Lagging power factors are inductive loads, meaning you must add a capacitive load to correct them.

Examples of machinery that uses a capacitive load include capacitors and buried cables.

How Does Phase Shift Impact the Power Factor?

Because the phase shift measures the difference between the voltage and the load current waves, it describes the efficiency of the power factor. Imbalance, aka phase shift, between waves indicates a less-efficient power factor.

Efficient power factors appear when the peaks and valleys of both waves remain in sync with one another. These power distribution systems won’t waste energy as they maintain equilibrium between the waves.

Types of Loads That Affect the Power Factor

As previously mentioned, loads refer to the apparent power in a system. We measure them with load currents. We compare these currents to the voltage waves from the power supply to determine a power factor.

The qualification of each load depends on the shape of the wave. We will include a simplified explanation of each, though scientifically, the measurements become much more complex.

Let’s review the three types of loads:

  1. Non-Linear: A non-linear load has an untraditional waveform referred to as “non-sinusoidal.” Scientists draw these types of waves in the same way as harmonics. Some examples of machinery with non-linear loads include temperature-controlled ovens and DC drives.
  2. Linear Resistive: Linear-resistive loads have a sinusoidal waveform. They intersect with the voltage at the zero coordinate and have a power factor of 100% because the waves stay in sync. Incandescent lighting and space heaters are two examples of this type of load.
  3. Linear Reactive: Linear-reactive waves are the most common and include both inductive and capacitive loads. Because the waveforms are out of sync with one another, they have less-efficient PF than purely resistive loads.

How Can the Power Factor Save Me Money?

To maximize your energy usage, all AC circuits in your home must have a PF of as close to 100% as possible. This indicates that the system wastes no power as it functions.

It is best to contact an expert electrician to find out the power factor of the AC circuits on your property. They use special devices to measure PF and know how to balance out the load current and voltage to increase the power factor.

Often, to balance the PF of certain AC circuits, an electrician will add either a capacitor or generator. This can save you a lot of money on wasted energy, as a balanced power factor means that an AC system uses all its power.

Looking To Maximize Your Power Factor in Oklahoma City, OK?

If you would like to learn more about how to balance the power factor of AC circuits on your property, contact Blue Sky Electric. Our founder, Justin Hopkins, remains committed to providing high-quality residential energy services with particular attention to detail.

We can help you install renewable energy, replace breaker panels, and even maximize your power factor. Contact us online to schedule your consultation today.