How to Choose the Right Phase Converter for Your Needs

Choosing a phase converter comes down to four decisions: series, HP size, voltage, and enclosure. Here is how to make each one correctly.

Decision 1 — Which Series?

  • NL Series (Auto-Start): Best for most shops. Starts automatically, no button. Choose NL for CNC machines, lathes, grinders, saws, and general shop equipment.
  • PL Series (Push-Button): Choose PL if you need manual start/stop or T1/T2 timer terminals to integrate with a magnetic starter.
  • NLA Series (AutoLink): Required for air compressors and HVAC. The digital AutoLink controller manages the high inrush current these loads produce. Standard NL/PL converters can trip or struggle with compressor startup.
  • NH/PH Series: For 460V three-phase equipment. Same auto-start/push-button choice as NL/PL but 460V output.
  • GPX Digital: If you want cloud monitoring, energy analytics, and auto-shutoff when equipment is idle.

Decision 2 — What HP Size?

Multiply your equipment HP by the load multiplier for your equipment type:

Equipment Multiplier
Saws, grinders, drill press 1.0x
Lathes, mixers, centrifugal pumps 1.5x
CNC, pumps, press brakes 2.0x
Compressors, HVAC, fans 2.5x

Decision 3 — Voltage?

Check your equipment nameplate. Most shop equipment is 230V three-phase — use the NL/PL/NLA series. If your equipment requires 460V, use the NH/PH series.

Decision 4 — Enclosure?

Standard NEMA 1 enclosures are fine for clean, dry indoor environments. If your shop is dusty (woodworking, concrete, grain, farm), specify a NEMA 4 enclosure when ordering.

Still unsure? Call (800) 417-6568 — our engineers will walk you through it in 5 minutes.

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Choosing the Right Converter — FAQ

What if I am between two HP sizes?

Always go up. A converter running at 70% of rated capacity runs cooler, produces better voltage balance, and lasts longer. The cost difference between adjacent sizes is modest.

Can I use my phase converter for a different machine later?

Yes — as long as the new machine's sized HP requirement does not exceed the converter's rating. Phase converters are not locked to specific equipment.

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Questions? Talk to an engineer.

Free sizing help. Made in Phoenix, AZ. Lifetime warranty on every unit.

Shop Phase Converters

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