The #1 Question We Get Asked
After 50+ years in the phase converter business, the most common question is simple: "What size do I need?"
The answer depends on three things:
- Your largest motor — the converter must match or exceed it
- Simultaneous loads — how many motors run at the same time?
- Starting requirements — some equipment needs extra power to start
Below is our complete sizing chart based on real-world installations.
Quick Sizing Rule
Converter HP ≥ Largest Motor HP + 50% of other simultaneous motors
Example: 20 HP main motor + 5 HP dust collector + 3 HP compressor running together
= 20 + (5 × 0.5) + (3 × 0.5) = 24 HP → get a 25 HP converter
Sizing Chart by Equipment Type
| Equipment | Typical HP | Recommended | Price From |
|---|---|---|---|
| Small CNC Mill (Haas Mini, Tormach) | 5-10 HP | GP10NL | $1,479 |
| Mid CNC (Haas VF-2/3, Fadal) | 15-20 HP | GP20NL | $2,393 |
| Large CNC (Haas VF-6+, DMG Mori) | 25-40 HP | GP40NL | $4,289 |
| Air Compressor (5-15 HP) | 5-15 HP | GP15NL | $1,887 |
| HVAC / Condenser | 3-10 HP | GP10NL | $1,479 |
| Table Saw (SawStop, Powermatic) | 5-7.5 HP | GP7NL | $1,323 |
| Full Woodworking Shop | 15-30 HP total | GP30NL | $3,239 |
| MIG/TIG Welder (Miller, Lincoln) | 10-25 HP | GP25NL | $2,617 |
| Irrigation Pump | 10-40 HP | GP40NL | $4,289 |
| Grain Dryer | 30-75 HP | GP75NL | $6,379 |
NL vs PL Series: Which Do You Need?
NL Series (Standard) — Best for shops running one large piece of equipment at a time. Simple, reliable, lifetime warranty. Most popular choice.
PL Series (Premium) — Built for facilities running multiple motors simultaneously. Better voltage balance under heavy multi-load conditions. Ideal for full machine shops, commercial HVAC, production facilities.
Not sure? Call us — we will tell you honestly which one you need. We would rather sell you the right converter than upsell you on features you do not need.
460V Equipment? You Need a Transformer Package
If your equipment runs on 460V or 480V three-phase but your service is 230V single-phase, you need a converter plus a step-up transformer. We sell these as packages (NLT and PLT series) for a seamless solution.
Still Not Sure? We Will Size It for Free
Send us your equipment nameplate (snap a photo and text it to us) and we will tell you exactly what you need. No charge, no obligation, no sales pressure.
(800) 417-6568
Mon–Fri 7AM–5PM MST | Free sizing help | Lifetime warranty