If you’ve ever tried to run industrial equipment in a shop or small facility, you’ve probably run into this problem. The building only has single-phase power, but the machine you want to use needs three-phase. This is extremely common with CNC machines, lathes, compressors, pumps, and other heavy-duty equipment.

Upgrading to utility three-phase power sounds like the obvious answer, until you see the cost or learn it’s not even available in your area. That’s where a phase converter comes in. It allows three-phase equipment to run using the single-phase power you already have.

Let’s break down how that actually works without getting buried in electrical jargon.

Why single-phase power creates limitations

Single-phase power is standard in homes and many commercial buildings. It works well for lighting, outlets, and basic tools. The problem shows up when you introduce motors designed for industrial use.

Three-phase motors are built differently. They rely on three separate power waves that are evenly spaced. This design lets the motor run smoother, start easier, and handle heavier loads without stressing the electrical system. When one or more of those phases is missing, the motor simply can’t operate the way it was designed to.

Without a solution, three-phase equipment connected to single-phase power may not start at all. If it does start, it may run hot, lose torque, or fail prematurely.

What a phase converter actually does

A phase converter solves this mismatch between available power and machine requirements. It takes the single-phase power coming from the electrical panel and creates an additional power leg. That extra leg allows the equipment to “see” three-phase power and operate normally.

This process is commonly referred to as single-phase to three-phase conversion. While the power created by a converter is not identical to utility-supplied three-phase, it is stable enough to run most machines when the system is sized correctly.

Understanding how phase converters work makes it easier to choose the right setup and avoid performance issues later.

How the conversion happens in simple terms

Single-phase power uses two main conductors. Three-phase power uses three conductors that are timed evenly apart. A phase converter takes the existing single-phase input and generates a third voltage sinewave that creates a natural phase shift.

Depending on the type of converter, this third phase can be created using electrical components, a rotating motor, or electronic controls. Once that third leg is established, the machine operates as if it were connected to a three-phase supply.

This is the foundation of a phase converter single-to-three phase system. The details vary by design, but the goal is always the same. Create a stable third phase so the equipment can run properly.

The different types of phase converters

Not all phase converters work the same way, and choosing the right one depends on the equipment it will run and how it’s used. Understanding the differences between available phase converters helps make sure the system matches the job.

Static phase converters are the simplest option. A static converter helps start a three-phase motor, but once the motor is running, it operates on single-phase power at reduced horsepower. These systems are usually best for light-duty motor applications where full output is not required.

Rotary phase converters use an idler motor to generate the third phase. Once running, the idler motor helps balance voltage across all three legs. This design is popular in shops that run heavier equipment or multiple machines.

Digital phase converters use solid-state electronics to actively monitor and adjust voltage. They are often chosen for voltage-sensitive CNC machines, elevators, or unattended setups because they provide consistent, well-balanced power.

Why phase converters make sense in real shops

A phase converter allows equipment owners to work with the power they already have. Instead of paying for costly utility upgrades or moving machines to another location, a converter provides a practical alternative.

Another benefit is flexibility. A properly sized system can support one machine or several, depending on the setup. It also opens up access to used or surplus three-phase equipment, which is often easier to find and more affordable.

When installed and sized correctly, a phase converter becomes a reliable part of the electrical system, not a temporary fix.

Clearing up common misconceptions

Some people worry that running three-phase equipment on a converter is unsafe. In most cases, problems come from poor sizing or improper installation, not from the converter itself. If properly sized and installed, a phase converter is a completely safe and effective alternative to utility three-phase.

Another misconception is that all converters behave the same. In reality, each type handles starting current, load changes, and voltage balance differently. Matching the converter to the application is just as important as choosing the right machine.

You can learn more about the different types of phase converters by visiting our Phase Converter 101 page.

Making three-phase equipment work with single-phase power

For many shops and facilities, single-phase power is simply the reality. A phase converter makes it possible to use three-phase equipment without major electrical changes. By creating a usable third phase, the system allows machines to start smoothly, run efficiently, and perform the way they were designed to.

Understanding how a phase converter’s single-to-three phase system works helps equipment owners make better decisions and get more value from their machines. When chosen carefully, a phase converter becomes a long-term solution.

If you have any questions about phase converters, contact North America Phase Converter Co. and one of our experienced technicians will assist you.