Technical Support
Phase Converters: Single Phase to Three Phase Power
Phase Converters: The Complete Buyer's Guide
Convert single-phase power to three-phase power for CNC machines, compressors, HVAC systems, and industrial equipment. Built in Phoenix, AZ with a lifetime warranty.
Call (800) 417-6568 — Free Sizing HelpWhat Is a Phase Converter?
A phase converter transforms single-phase electrical power into three-phase power, allowing you to run industrial equipment in locations where three-phase utility service isn't available. If you have a shop, farm, or facility with only single-phase service from the utility company, a phase converter is the most reliable and cost-effective way to power three-phase motors, CNC machines, compressors, and HVAC systems.
Most residential and rural properties in the United States receive single-phase power (240V). But industrial equipment — including CNC mills, lathes, air compressors, welders, and commercial HVAC units — typically requires three-phase power (240V or 480V, three-phase). Instead of paying $10,000–$50,000+ to have the utility company run three-phase lines to your property, a phase converter gives you the same power for a fraction of the cost.
Types of Phase Converters
Rotary Phase Converter
Most Popular — Best for All Applications
Uses an idler motor to generate true, balanced three-phase power. Handles motor starting loads, hard-starting equipment (compressors, hydraulics), and sensitive electronics (CNC machines, VFDs). The industry standard for reliability.
- Runs any three-phase equipment
- Handles hard-starting loads
- Balanced voltage output
- 3 HP to 100+ HP available
- Lifetime warranty (Phoenix models)
Static Phase Converter
Budget Option — Limited Use
Uses capacitors to start a three-phase motor but only delivers single-phase power while running. The motor operates on two of three phases at reduced efficiency. Cannot run CNC machines, compressors, or any equipment with electronic controls.
- Lowest upfront cost
- Only starts motors — doesn't sustain 3-phase
- Cannot run sensitive electronics
- Motor runs at reduced power (~2/3)
VFD (Variable Frequency Drive)
Single Motor Only
Converts single-phase to three-phase electronically for one motor at a time. Works for simple, single-motor applications but creates problems with CNC machines (a VFD running through another VFD causes failures) and generates electrical noise that damages sensitive controls.
- One motor per VFD
- Cannot power multiple machines
- Runs hot, shorter lifespan
- Not recommended for CNC or compressors
Why Rotary Phase Converters Are the Industry Standard
Over 90% of professional shops, farms, and industrial facilities choose rotary phase converters. Here's why:
- True three-phase output — balanced voltage across all three legs, just like utility power
- Run anything — CNC machines, compressors, welders, HVAC, pumps, grain dryers, and more
- Handle hard starts — compressors and hydraulic presses draw massive starting current; rotary converters handle it
- Run multiple machines — one converter powers your entire shop
- Built to last — Phoenix Phase Converters come with a lifetime warranty on the panel and a 10-year motor warranty
- Clean power — safe for CNC controls, PLCs, and VFDs inside equipment
How to Size a Phase Converter
The basic rule: double the horsepower of your largest motor. If you're running a 10 HP compressor, you need at least a 20 HP phase converter. Running multiple machines simultaneously? Add up all the HP running at the same time, then double it.
| Your Equipment | Motor HP | Recommended Converter | Starting Price |
|---|---|---|---|
| Small lathe, drill press | 1–3 HP | GP3NL (3 HP) or GP5NL (5 HP) | $749 |
| Milling machine, small CNC | 3–5 HP | GP10NL (10 HP) | $1,955 |
| CNC mill (Haas VF-2), compressor | 5–10 HP | GP20NL (20 HP) | $2,663 |
| Large CNC, multiple machines | 10–20 HP | GP40NL (40 HP) | $5,600 |
| Full machine shop, large HVAC | 20–40 HP | GP60NL (60 HP) | $7,670 |
| Industrial facility, large compressor | 40–100+ HP | GP100NL (100 HP) | $11,830 |
Not sure what size you need? Call us at (800) 417-6568. Tell us your equipment and we'll size it for free in under 5 minutes. We've done this for thousands of customers.
Common Applications for Phase Converters
Phase Converter vs. Utility Three-Phase: Cost Comparison
| Phase Converter | Utility 3-Phase Service | |
|---|---|---|
| Upfront Cost | $749 – $12,000 | $10,000 – $100,000+ |
| Installation Time | 1–2 hours (DIY or electrician) | 2–12 months (utility scheduling) |
| Monthly Cost | Electricity only (no demand charges) | $50–$200/month demand charges |
| Portable? | Yes — move it if you relocate | No — permanent installation |
| Warranty | Lifetime (Phoenix Phase Converters) | N/A |
Why Choose Phoenix Phase Converters?
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Built in Phoenix, AZ
Manufactured in our own facility with 50+ years of engineering experience
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Lifetime Warranty
Every panel carries a lifetime warranty. Motors carry a 10-year warranty.
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Real Phone Support
Call us and talk to the people who build these converters. We size every system personally.
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Ships from 50+ Warehouses
Most orders ship same day. Delivery in 1–5 business days nationwide.
Frequently Asked Questions About Phase Converters
How much does a phase converter cost?
Phase converter prices range from $749 for a 3 HP unit to $12,000+ for 100 HP industrial systems. The most common sizes (10–30 HP) run between $1,955 and $4,375. This is a fraction of the cost of having utility three-phase service installed, which can run $10,000–$100,000+.
Can a phase converter run a CNC machine?
Yes — rotary phase converters produce true, balanced three-phase power that is safe for CNC machines, including Haas, Mazak, DMG Mori, Doosan, and all other brands. A static converter or VFD cannot safely power a CNC machine because the electronic controls require balanced three-phase voltage on all three legs.
What size phase converter do I need for a compressor?
For air compressors, size the converter at 2.5 times the compressor motor HP because compressors are hard-starting loads. A 10 HP compressor needs at least a 25 HP phase converter. A 15 HP compressor needs a 40 HP converter.
What is the difference between NL and PL series?
The NL series is the standard rotary phase converter — reliable, efficient, and our most popular. The PL series adds a built-in start/stop button and voltage monitor that automatically shuts the converter off if anything is wrong. The PL is preferred for shops where equipment protection is a priority.
Can I run multiple machines on one phase converter?
Absolutely. One phase converter can power your entire shop. Just add up the HP of everything you plan to run simultaneously, then double it. Most customers run 2–5 machines off a single converter.
How hard is it to install a phase converter?
Most customers have their electrician install it in 1–2 hours. It connects between your electrical panel and your equipment. We provide wiring diagrams and walk every customer through the installation by phone before they fire it up.
Ready to Power Your Equipment?
Call us for free sizing help. We'll recommend the right converter for your application in under 5 minutes.
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