The GP50/100NL DualZone rotary phase converter pairs two 50 HP idler motors to deliver a full 40 HP of continuous three-phase power — with more combined core steel and copper winding than any single 100 HP idler motor could provide. Because the two idlers start one at a time, they do not create a simultaneous two-motor starting event. Sequential starting reduces peak starting inrush. Electrical sizing notice: sequential starting does not reduce the continuous current required by the connected load. A qualified electrician must size the service, breaker, feeder, and disconnect using the converter nameplate, actual connected load, installation conditions, and applicable electrical codes.
⚡ How GP50/100NL Uses Sequential Starting
Two 50 HP TEFC cast-iron idlers start in sequence — never together. First idler spins up alone, then the second engages once the first is at speed. Sequential starting avoids starting both idlers at once and reduces the peak starting event. It does not change the continuous input current required for the connected load. Follow the product nameplate and have a qualified electrician determine the required service, breaker, feeder, and disconnect.
Because two 50 HP motors have more total core steel and copper winding than a single 100 HP motor — you also get better voltage balance, cleaner three-phase waveform, and more usable running HP than a same-rated single-idler unit could deliver.
| Model | GP50/100NL |
| Total Running HP | 100 HP three-phase |
| Idler Configuration | Two 50 HP TEFC idlers (sequential start) |
| Peak Starting Inrush | Equivalent to single 50 HP idler |
| Largest Starting Motor | 50 HP |
| Single Phase Wire Size | 2/0 AWG (under 50 ft) |
| Idler Motor Wire Size | 3 AWG |
| Primary Idler Motor | 50 HP — 326T NEMA Frame, TEFC cast-iron |
| Secondary Idler Motor | 50 HP — 326T NEMA Frame, TEFC cast-iron |
| Electrical Panel | NEMA 4 sealed — indoor/outdoor rated |
GP50/100NL vs. a single-motor 100 HP converter
| GP50/100NL DualZone | Single 100 HP Converter | |
|---|---|---|
| Total continuous three-phase HP | 100 HP | 100 HP |
| Combined idler mass (core steel + winding) | Two 50 HP motors — more than a single 100 HP | One 100 HP motor |
| Peak starting inrush | Single 50 HP idler | Full 100 HP idler |
📦 What's Included
- ✅ Two 50 HP TEFC idler motors (cast iron, continuous duty)
- ✅ Pre-wired DualZone Electrical Control Panel
- ✅ Sequential-start controller (staggered idler startup)
- ✅ Integrated AutoLink Start System (soft-start on both idlers)
- ✅ Complete Installation Manual & Wiring Diagrams
- ✅ Lifetime Warranty — motors & panel
Why Choose the GP50/100NL DualZone
The two idlers start one at a time instead of simultaneously, reducing the peak starting event. Continuous service and conductor sizing must still be based on the actual connected load and nameplate requirements.
Two 50 HP idlers deliver more combined core steel and copper winding than a single 100 HP motor. Result: tighter voltage balance across all three legs — crucial for the efficient, quiet, and long-lasting operation of your equipment.
Sequential-start means only one 50 HP idler spins up at a time. Your utility feeder never sees a 100 HP inrush event — protecting service transformers and neighbor loads.
Higher combined idler mass converts more efficiently under load. You get more real, usable three-phase HP at the machine terminals than a same-rated single-idler design.
Our Integrated AutoLink streamlines the process of connecting a transformer to the phase converter, saving time, money, and space. Most of the transformer-side wiring is done for you at the factory — enjoy a hassle-free installation.
Expertly engineered for a clean, easy install. Comprehensive installation manuals, step-by-step videos, and a dedicated Phoenix representative assigned to your order — done right the first time.
Phoenix Phase Converters are built to last — unmatched durability and reliability, designed to withstand the toughest industrial conditions. Consistent performance and long-term investment protection, backed by our lifetime warranty.
Every DualZone converter is assembled, wired, and tested in our Phoenix, Arizona facility. American-built quality with direct-from-manufacturer pricing and engineering support just a phone call away.
Integrated AutoLink — Converter + Transformer, Ready to Wire
The AutoLink option pre-integrates a matched three-phase step-up transformer with the phase converter, so the panel-to-transformer wiring is already done. Add DualZone to that setup and you have 100 HP of three-phase 460V power from a single-phase 230V service — with no field engineering.
NEMA 4 / IP65 Weatherproof Control Panel
Every panel is rated NEMA 4 / IP65 — fully sealed against dust and water jets. Install indoors or outdoors with confidence, even in harsh shop environments.
Heavy-Duty TEFC Idler Motors
Both idlers are Totally Enclosed Fan Cooled with cast iron frames, precision-balanced rotors, and sealed bearings. Built for decades of continuous industrial service.
🏗️ Common Applications for the GP50/100NL
Ideal for shops and facilities that need substantial three-phase output with sequential idler starting.
Talk to an engineer — we'll size the right DualZone converter for your service and load
🎥 See It In Action
Inside the Build — Engineering & Performance
NL Model — 9 Wire Motor Connection (230V)
TEFC vs ODP — Which Motor Is Right?
Phoenix Phase Converters — Full Overview
Talk to an engineer — we'll size the right DualZone converter for your service and load
GP50/100NL Technical Documentation
Complete specs, wiring diagrams, and installation instructions for this DualZone phase converter
The GP50/100NL is a 100 HP DualZone rotary phase converter designed and manufactured by Phoenix Phase Converters in Phoenix, Arizona. It pairs two 50 HP TEFC cast-iron idler motors that start sequentially, delivering a full 100 HP of continuous three-phase output. Because the combined core steel and copper winding of two 50 HP motors exceeds that of any single 100 HP motor, DualZone converters deliver cleaner three-phase power, better voltage balance, and more usable running HP than any single-idler design at the same rating.
Not sure whether DualZone is the right fit for your service capacity and equipment list? Our engineers can help you calculate the correct HP and review your connected load and electrical requirements. Call us at (800) 417-6568 or download the datasheet above.
Helpful guides
Not sure which converter fits your application? Our knowledge hub covers everything:
- How to size a rotary phase converter — step-by-step sizing guide with common scenarios
- Phase converter FAQ — quick answers to the most common questions
- Rotary vs static comparison — see why rotary is usually the right choice
