How to run a 3-Phase Motor in your garage/home with single phase power

by Jorge Alvarez August 24, 2021

We found 3-Phase Motors in: Drill Press, Lathes, Milling Machines, Air Compressors, etc. BUT at home/shop we can't make it run because we don't have 3-Phase Power! What can we do?

Common Solutions:

1. Replace the Motor with a Single-Phase Motor

✅ Simple and direct solution.
❌ Expensive—replacement motors can cost a lot.
❌ Higher electric bills—single-phase motors draw more amperage for the same horsepower.
❌ May involve modifications to the machine (mounting, pulley alignment, etc.).

2. Use a Static Phase Converter

✅ Lower cost than replacing the motor.
✅ Allows you to run your existing 3-phase motor on single-phase power.
✅ Saves money—3-phase motors are more energy-efficient and draw less amperage per horsepower.
✅ Keeps your equipment original and intact—no modifications needed.

In General, Amps/HP Ratings can be estimated as follows:

115 Volts Motor - Single Phase: 14 Amps/HP
230 Volts Motor - Single Phase: 7 Amps/HP
230 Volts Motor - 3-Phase: 2.5 Amps/HP.
Example:
1 HP Motor Single Phase with 115V will draw: +/- 16 Amps.
1 HP Motor Single Phase with 230V will draw: +/- 8 Amps.
1 HP 3-Phase Motor with 230V will draw: +/- 3.6 Amps.

The Power Company charges for the KW or KVA we use, KW= Amps X Volts, that means the higher the Amperage the more they will charge. (This is an aproximation) But as you can see, you'll pay more. Now, IF you use a Staic Phase Converter you will be saving money and energy. Static Phase Converters are an Economical Solution for the Problem, You will be able to run your 3-Phase Motor at 60% of the Motor's rated HP!

For Air Compressors, water pumps, etc. with pulleys, you'll need to reduce the Motor's Pulley's Diameter by 1/3 or use a 50% bigger Motor, or you can use a Rotary type Phase Converter which will give full power.

Let me know your specific machine setup, and I can recommend the best converter type and size!

Write to us at: info@aucontrols.com with your needs or projects, we will help you. Or Visit us at: www.aucontrols.com