Pro-Line Rotary Phase Converters 101
The Pro-Line rotary phase converter converts single-phase power into balanced three-phase power, so you can run CNC machines, mills, lathes, table saws, and other three-phase equipment wherever utility three-phase power is not available.
What Is a Pro-Line Rotary Phase Converter?
Not all rotary phase converters are built the same – the Pro-Line is engineered as a premium, all-in-one unit for shops that need dependable, machine-ready three-phase power.
Built in Wisconsin, the Pro-Line is engineered to go beyond basic phase conversion. It comes standard with CNC voltage balancing, a built-in motor starter, a digitally controlled start circuit, soft start, and Total Power Shutoff Protection. Models are available from 3 HP to 100 HP and carry a 10-year parts/lifetime labor warranty.
For most shops running standard motor, resistive, and inductive loads – CNC machines, mills, lathes, table saws, and similar equipment – the Pro-Line is the right starting point.
How Does a Pro-Line Rotary Phase Converter Work?
A rotary phase converter works by spinning an idler generator motor on single-phase power to generate the missing third electrical phase. Once running, the idler motor acts as a generator, producing a third sine wave and delivering balanced three-phase output to your equipment.
The Pro-Line pairs that idler generator with a control panel that manages starting, voltage balancing, and protection. The control panel handles the start sequence using a patented differential-voltage sensing system, monitors for phase failure, and shuts down all three legs at the same time if power is lost, eliminating the single-phasing risk that cheaper designs leave open.
Run capacitors in the panel correct the power factor and keep voltage balanced phase-to-phase to within 5%, which is tight enough for CNC mills, CNC lathes, and other precision equipment.
How Do I Choose the Right Pro-Line for My Equipment?
The Pro-Line is the right choice for most standard three-phase applications.
Woodworking Shop
Typical Equipment: Table saws, radial arm saws, chop saws, CNC routers, lathes, shapers, molders, jointers, planers, edgebanders, drill presses, boring machines
Why the Pro-Line suits it: Handles multiple simultaneous loads, unlike static converters or VFDs. For high-inertia loads like dust collectors, consider the Smart-Boost™ instead.
Metalworking & Machine Shop
Typical Equipment: Bandsaws, shears, waterjets, lasers, EDMs, gearhead lathes, milling machines, CNC mills, press brakes, surface grinders, cylindrical grinders, welders, ironworkers, battery chargers
Why the Pro-Line suits it: CNC machinery is sensitive to voltage fluctuations. The Pro-Line’s phase-to-phase voltage balance of 5% or better keeps even the most sensitive controls running cleanly.
Food Service & Commercial Kitchens
Typical Equipment: Dough mixers, ovens, rotisseries, ice cream machines, ice makers, refrigeration units, food processors
Why the Pro-Line suits it: Installing a phase converter is typically faster and less expensive than bringing in utility three-phase service – and if a business moves, the converter moves with it.
Agricultural
Typical Equipment: Center pivot irrigation systems
Why the Pro-Line suits it: Most farming operations are in rural areas with no access to three-phase utility power. For outdoor installations, specify a NEMA 3R enclosure and TEFC idler motor.
Automotive & Industrial
Typical Equipment: Chain hoists, cranes, parts washers and welders
Why the Pro-Line suits it: Automotive and collision shops often run several heavy three-phase machines on site. A phase converter is usually more cost-effective than extending utility three-phase service.
Sizing Your Pro-Line Rotary Phase Converter
Proper sizing is critical: an undersized unit struggles to sustain three-phase output, runs hot, and wears out early. Sizing is based on the horsepower (or amperage) of your largest motor and how hard it is to start. Use the tool or the chart below, or call us at 877-545-2926 for free sizing help.
Quick Sizing Chart for Pro-Line Rotary Phase Converters
| Phase Converter Model | Motor Loads (Horsepower) | CNC, Resistive & Inductive Loads | Shop | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Easy | Med | Hard | Very Hard | Total Amps | Total kVA | Total kW | Spindle HP | ||
| PL-3 | 2.5 | 2 | 1.5 | 1 | 4 | 1.6 | 1.1 | 1.5 | Shop now |
| PL-5 | 3 | 3 | 2 | 1.5 | 7 | 2.9 | 1.7 | 2.5 | Shop now |
| PL-7 | 5 | 5 | 3 | 2.5 | 11 | 4.5 | 2.2 | 3 | Shop now |
| PL-10 | 7.5 | 6 | 5 | 3 | 15 | 6 | 3.7 | 5 | Shop now |
| PL-15 | 10 | 7.5 | 6 | 5 | 20 | 8 | 5.6 | 7.5 | Shop now |
| PL-20 | 15 | 12 | 10 | 7.5 | 25 | 11 | 7.7 | 10 | Shop now |
| PL-25 | 20 | 15 | 12 | 10 | 30 | 13 | 9.5 | 12 | Shop now |
| PL-30 | 25 | 20 | 15 | 10 | 37 | 15 | 11.8 | 15 | Shop now |
| PL-40 | 30 | 25 | 20 | 15 | 50 | 21 | 15.5 | 20 | Shop now |
| PL-50 | 40 | 30 | 25 | 20 | 61 | 25 | 21.5 | 25 | Shop now |
| PL-60 | 50 | 40 | 30 | 25 | 72 | 30 | 26.5 | 30 | Shop now |
| PL-80 | 60 | 50 | 40 | 30 | 100 | 41 | 29.6 | 40 | Shop now |
| PL-100 | 75 | 60 | 50 | 40 | 122 | 50 | 37.3 | 50 | Shop now |
How do I size and install a Pro-Line Rotary Phase Converter?
Watch our step-by-step sizing and installation walkthrough below. Prefer to talk it through? Call 877-545-2926, and we’ll help you find the right converter for your setup.