All About Three-Phase Air Compressor Wiring

Posted on: October 14, 2021

Air compressors wired for 3-phase power will not work if you try to plug them into a single-phase system. Three-phase plugs have a different design. Even if they did fit, single-phase power would be insufficient to turn on your equipment. If you have a three-phase compressor and you only have access to single-phase power, we’ll help you wire it so you can keep using your machine.

What Is Three-Phase Power?

In the U.S., most of the electrical outlets you encounter use single-phase power. These outlets have a power (phase) wire and a neutral (ground) wire. In most cases, these systems branch off from a three-phase input that feeds into the property that is scaled-down using transformers.

Three-phase power is how the power plant sends electricity out to the community. This delivery system can handle heavier loads. Three-phase is also popular in the business and industrial sectors for powering heavy equipment and machinery. Compared to the properties of single-phase power, three-phase is more consistent, produces fewer vibrations and is more efficient.

The Requirements for Wiring Three-Phase Power

If your air compressor requires three-phase power and you only have single-phase outlets available, you can wire your machine to work — but you must meet a few basic requirements. Before you take anything apart, check your:

  • Compressor motor: The motor should have a label that tells you whether or not your compressor uses three-phase power. In most cases, three-phase air compressors operate off 230 volts.
  • Electrical panel: Your main electrical panel should also have an information label. If the label says you have 120/240 volts and 125 amps, you have single-phase power.

Three-Phase Air Compressor Wiring Systems

It is impossible to take three-phase air compressor wiring and connect it directly to a single-phase panel — they are incompatible. Instead, you can take three-phase wiring and run it through a secondary system that converts your 120/240 system into the appropriate voltage. Several options are available, with the most popular being:

  • Static converters: A static converter takes your house power and uses it to supply a series of capacitors contained within the circuit. The capacitors fill with stored energy until they have enough charge to start your compressor motor. Once the capacitors release their load, the converter powers the motor at two-thirds capacity using two single-phase power lines.
  • Rotary phase converters: Another option to connect three-phase air compressor wiring to single-phase power is to use a rotary phase converter. Rotary converters transform 120/240 volt power into three-phase with the same accuracy you get from an installed system, and sometimes better. These converters stay powered to help balance the load during operation.
  • Variable frequency drives: A variable frequency drive (VFD) uses simple technology to generate three-phase power using a single-phase input. These devices produce reliable three-phase power, and you can change their frequency to get more or less output from your compressor motor. VFDs are often the most expensive option but offer the highest number of advantages.

Find the Right Compressor

At Quincy Compressor, we produce an extensive selection of compressors compatible with single- and three-phase power. If you are in the market for a new air compressor and want to upgrade to one that matches your current electrical setup, we can help you. Contact us online today to get expert assistance.