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How to Wire a Rotary Phase Converter


Even though wiring a Rotary Phase Converter is a favorite DIY project, I do not recommend doing that if you are just a beginner. If you got your RPC from a good reputable company, instructions should be easy to follow (at least they will not be in Chinese).

Now that you got your brand new Rotary Phase Converter or have everything ready to build one yourself, you need to know how to connect wires. If you don’t really understand your instructions or need more information on how to connect wires (and you are putting it together yourself), I will include some resources and wiring diagrams in this article.

Also, video installation instructions are available from some manufacturers of Rotary Phase Converters and they will be included as well. Here are some general instructions for connecting your Rotary Phase Converter:

  • Step 1. Disconnect the power from the circuit!
  • Step 2. Check if the circuit is disconnected with a multimeter (sorry, but this is important).
  • Step 3. Install double pole 220 VAC breakers (for their sizes, refer to the instructions manual). The same goes for your wire gauge. The company that provided you with the motor, should give you the details.
  • Step 4. Connect single-phase power to the terminals  marked L1 and L2 through the main disconnect switch or use diagrams for different wiring ideas, like this one:

We have more wiring diagrams in this article: “Rotary Phase Converter Wiring Diagram“. Here is a quick infographic (or short summary of wiring) for your reference .

Testing your three-phase converter

You can start your idler motor with either a “pony” motor (belt-drive arrangement), a start capacitor (electrically), or just by pulling on something to get its shaft spinning, the third leg of power should be generated for your equipment. Here is an interesting video on that:

Simple Rotary Phase Converter and info on Phase Rotation Meters ||| Final 3 Phase Video

The starting capacitor needs to be removed from the circuit, once your idler motor-generator gets going. You may also include run capacitors to balance voltages between the three legs:

You can add more run capacitors in parallel for bigger units. The same goes for the start capacitors, which could be wired in parallel as well.

** Warning! Working with electricity is dangerous and is not recommended if you are not a qualified licensed electrician.

Rotary Phase Converter installation instructions

Now, let’s look at installation instructions from different manufacturers:

North America Phase Converter Co.

This is how the installation is done for North America (or NAPCco) Phase Converters. The video of the installation in the instruction manual in PDF is also included.

** Very Important! Before you get started, check your local electrical codes. Disconnecting the power before you start working is a must.

  • Step 1. Open the enclosure and remove a backplate.
  • Step 2. Mount your enclosure.
  • Step 3. Remove knockouts and attach fittings with connectors.
  • Step 4. Check for the correct wire size by using the chart below.
  • Step 5. Attach incoming single-phase power to L1 and L2 terminals.
  • Step 6. There are two sets of output terminals in the power distribution block. The first set is for your idler generator and the second set is for your load. They are labeled: T1, T2, T3 (see diagram below). Idler motor should be connected to the first set of terminals (according to the diagram on it). After that, your load should be connected to the second set of output terminals in the distribution block.
  • Step 7. Ground your equipment.

Here are more detailed instructions from this company:

North America Phase Converters 3

Here is a basic wiring diagram from this company and official instruction manual(external link):

This is a wire sizing diagram (2.2) that they are referring to:

Refer to their manual for more detailed info and instructions.

American Rotary

Here is an installation video from American Rotary and some of their Rotary Phase Converter’s wiring diagrams (external link):

American Rotary Phase Converter Install

Phoenix Phase Converters

Here are some wiring diagrams in PDF format (external link) from Phoenix Phase Converters and an installation video:

Phoenix Phase Converter Installation Video - Push Button Models

Steelman Industries

Here are some diagrams from Steelman Industries (H-A-S) converters:

Here (external link) is their line of Rotary Phase Converters.


Here (external link) are some wiring diagrams from TEMCo.

DIY Rotary Phase Converter

There is a lot of information out there on how to build a Rotary Phase Converter and a reason for its popularity is that in many cases your equipment does not require good quality power. If you are not sure if your equipment will survive the rough power that your DIY unit will produce, it’s better that you go with a solid UL-listed Rotary Phase Converter from a reputable manufacturer.

They say that building your own RPC is not complicated, but balancing it out with Run Capacitors, could be a little tricky. The problem is usually in picking the proper size capacitors and going through wiring schemes that don’t always work in the beginning.

But if you are determined and have the skills, don’t give up and it will work out (as long as you are careful). Here is an interesting do-it-yourself video:

How to build a rotary phase converter

Hope this article will help you in some way.

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