25 HP Rotary Phase Converter — Who It's For

The GP25NL sits in the sweet spot for serious commercial shops and industrial operations. At 25 HP total running capacity with the ability to start motors up to 12 HP, this converter handles the kind of equipment found in professional machine shops, commercial woodworking operations, and mid-size manufacturing facilities.

Common applications include:

• Professional CNC shops running VMCs (Vertical Machining Centers), CNC lathes, and tool changers with spindles up to 10–12 HP
• Commercial woodworking with wide-belt sanders, moulders, large planers, and multi-head boring machines
• Metal fabrication shops running plasma tables, larger MIG/TIG welders, hydraulic press brakes, and ironworkers
• Agricultural and grain operations powering large grain dryers, auger systems, and irrigation pumps up to 12 HP
• Food processing facilities running mixers, conveyors, and refrigeration compressors
• Commercial HVAC operations running 10+ HP compressors for testing or installation

What the GP25NL Can Power

With 25 HP of total running capacity and a 12 HP single-motor starting limit, here's what your shop layout might look like:

• A 10 HP CNC vertical mill + a 7.5 HP air compressor + a 5 HP coolant pump (not all starting at once)
• A 12 HP wide-belt sander running alongside a 10 HP dust collector
• Multiple machines in a job shop — lathe (5 HP), mill (7.5 HP), surface grinder (3 HP), and compressor (7.5 HP)
• A 10 HP irrigation pump with ancillary 3-phase controls and a backup pump

Sizing Context

Choose the GP25NL when your largest single motor is 12 HP or less and your total running 3-phase load stays under 25 HP. If you have hard-starting loads — like scroll compressors, hermetic compressors, or heavily-loaded CNC spindles that start under load — consider our DualZone models which use patented technology specifically designed for high-inrush applications. If your largest motor exceeds 12 HP, step up to a 30 HP or 40 HP converter.

Installation Overview — GP25NL

As an NL (No Link) model, the GP25NL ships as a control panel — you supply and wire your own 25 HP idler motor. This is the most economical option when you have access to a suitable 3-phase motor locally.

Key Installation Requirements

• Input Power: 230V single-phase
• Minimum Service Size: 50 KVA (200A) — verify your utility service can support this draw
• Breaker Size: 60A minimum, 120A maximum — double-pole breaker in your main panel
• Single-Phase Supply Wire: 2 AWG copper (for runs under 50 feet). For 50–100 foot runs, use 1/0 AWG to maintain voltage within NEC limits
• Idler Motor Wire: 4 AWG copper between panel and idler motor
• Idler Motor: 25 HP, 1800 RPM, 3-phase motor (NEMA 284T frame). Weight: approximately 406 lbs (12" × 12" × 20")

A 200A service is standard for most commercial properties and many newer residential services. If you're on a 100A residential service, you'll likely need a service upgrade before installing a 25 HP converter. Our installation manual covers complete wiring procedures. For a plug-and-play solution, the GP25PL (Pre-Linked) comes with the idler motor pre-wired and factory-tested.

Why Phoenix Phase Converters?

• Lifetime Warranty: Every Phoenix converter carries a lifetime warranty. Not 1 year, not 5 — lifetime. We stand behind our engineering.
• 90-Day Money-Back Guarantee: If the converter doesn't perform as promised, return it for a full refund. No hassle.
• Built in America: Designed and manufactured in Phoenix, Arizona. No offshore assembly, no mystery components.
• 50+ Years of Experience: Our founder Daniel Floreancig has been building phase converters for over five decades. That experience shows in every unit we ship.
• Properly Engineered: Our capacitor banks, contactors, and protection circuits are sized for the rated load — not the minimum that might work on paper.

Frequently Asked Questions — 25 HP Phase Converter

I have a 200A residential service. Is that enough for a 25 HP converter?

Yes, a 200A service is sufficient for the GP25NL. The converter requires a 50 KVA (200A) service minimum. However, keep in mind that the converter breaker (60–120A) is sharing that 200A panel with the rest of your house. If you're running the converter at full load plus A/C, electric range, and other heavy loads simultaneously, you may trip the main breaker. Many customers install a dedicated subpanel or meter for the shop.

Can I run CNC machines on this converter?

Absolutely. The GP25NL provides clean, balanced 3-phase power suitable for CNC equipment. For CNC machines with sensitive electronics and hard-starting spindles, we recommend our DualZone models which provide an extra voltage boost during motor startup. The standard GP model works great for most CNC routers and mills with spindles up to 10–12 HP.

How does the 25 HP NL compare to the 25 HP digital (GPX25L)?

The GP25NL is a traditional rotary phase converter — reliable, proven technology with no circuit boards to fail. The GPX25L is our digital model with microprocessor-controlled voltage balancing. The digital model provides tighter voltage regulation (important for sensitive CNC equipment) but costs more. For most shop applications, the GP25NL delivers excellent power quality at a lower price point.