Static Phase Converters vs. DPS Digital Phase Shifter — What Is the Difference?
Not all phase converters are created equal. Understanding the difference between static, digital, and rotary technology helps you pick the right unit for your application.
Static Phase Converters
A static phase converter uses capacitors to generate a phase-shifted third leg — no moving parts. It is the least expensive option, but comes with significant tradeoffs:
- Generates the third phase only during startup — at full running speed, your equipment runs on two legs (single-phase), not true three-phase
- Motor runs hotter, draws more current, delivers only 60–70% of rated power
- Fine for light, intermittent use on a single simple motor
- Not suitable for CNC machines, multi-motor applications, or continuous-duty loads
DPS Digital Phase Shifter
The DPS (Digital Phase Shifter) is a step up from static converters. It uses electronic switching to maintain the third phase more consistently than a pure capacitor design. Output is more balanced than static, but still not equivalent to a rotary or utility three-phase source.
Rotary Phase Converter (Phoenix)
A rotary phase converter generates a true third phase via an idler motor — providing balanced three-phase output under full load, identical in quality to utility three-phase. It is the correct choice for:
- CNC machining centers
- Multi-motor shops
- Equipment with internal VFDs or servo drives
- Continuous-duty industrial applications
Quick Comparison
| Feature | Static | DPS Digital | Rotary |
|---|---|---|---|
| True three-phase at full load | No | Partial | Yes |
| CNC / VFD compatible | No | Limited | Yes |
| Multi-motor support | No | No | Yes |
| Continuous duty | No | Limited | Yes |
| Cost | Lowest | Medium | Medium–High |
For any serious shop application, a rotary phase converter is the only correct choice. Call (800) 417-6568 for free sizing help.
Ready to get powered up?
Free sizing help. Made in Phoenix, AZ. Lifetime warranty.
Shop Phase ConvertersRelated Articles
Static vs Rotary — FAQ
Can a static converter run a Haas CNC?
No — static converters only generate the third phase during startup, then revert to two-leg (single-phase) operation. CNC machines require true balanced three-phase continuously during operation. A static converter will cause immediate faults on any CNC machine.
I have a static converter and my motor runs hot — why?
Your motor is running on two legs, drawing unbalanced current, generating excess heat. The motor is doing the work of a three-phase motor on single-phase power — it is overloaded by design. Upgrade to a rotary phase converter to eliminate this problem.
Is a DPS digital phase shifter the same as a rotary phase converter?
No — a DPS uses electronic switching to approximate a third phase. Output quality is better than static but still not equivalent to a true rotary converter under heavy or continuous load. For serious shop use, a rotary phase converter is the correct choice.
My static converter works fine on my equipment — should I still upgrade?
If your equipment runs correctly, stays cool, and performs at full rated capacity, your static converter may be adequate for that specific simple load. However, if you add a CNC machine, a second motor, or any continuous-duty equipment, a rotary converter is necessary.
Related Articles
- How to Size a Rotary Phase Converter
- What Is a Rotary Phase Converter?
- Rotary vs Digital Phase Converters
- Phase Converter FAQ
Questions? Talk to an engineer.
Free sizing help. Made in Phoenix, AZ. Lifetime warranty.
Shop Phase Converters