Technical Support
Sizing Help
Phase Converter Sizing Guide
Get the right size converter for your equipment. Free sizing help from our engineers.
The Golden Rule of Sizing
Your converter HP should equal your largest motor’s HP, PLUS any additional loads running simultaneously.
Example: If your largest motor is 10HP and you also run a 5HP compressor at the same time, you need at least a 15HP converter.
Quick Sizing in 3 Steps
Most customers can size their converter in under 2 minutes.
1
List Your Equipment
Write down every 3-phase motor you plan to run. Check the nameplate for HP rating.
2
Add Up Total HP
Total the HP of all motors that will run at the same time. This is your minimum converter size.
3
Choose Your Converter
Select a converter equal to or greater than your total HP. When in doubt, size up.
Common Equipment HP Reference
Not sure how much HP your equipment needs? Here are typical ranges.
Pro Tips for Accurate Sizing
✅ Always size up, not down. A converter that is slightly oversized will run cooler and last longer. An undersized converter will struggle and may trip breakers.
⚡ Consider startup surge. Some equipment (compressors, saws) draws 3-6x rated HP on startup. If you have hard-starting loads, size up or consider our DualZone series.
🔌 Check your incoming voltage. Most residential/commercial single-phase service is 240V. If you have 208V or 480V service, let us know — we build for all voltages.
Need Help Sizing Your Converter?
Our engineers will size it for you — free. Just tell us what equipment you are running.
Talk to a Phase Converter Engineer
📞 (800) 417-6568Free sizing help • Lifetime warranty • Made in USA • Mon–Fri 7AM–5PM MST