A servo regulator corrects voltage steplessly and precisely with a servo-driven variac; a static regulator corrects in steps but very fast using electronic switches. Choose servo when accuracy matters most, and static when speed and the absence of mechanical parts matter most.
Quick comparison
| Feature | Servo regulator | Static regulator |
|---|---|---|
| Correction type | Stepless (continuous) | Stepped |
| Output accuracy | Typically ±1% – ±3% | Depends on tap count, generally ±1.5% – ±5% |
| Correction speed | Limited by servo motor (slower) | Millisecond range (very fast) |
| Moving parts | Yes (servo motor, brush) | None |
| Maintenance | Periodic (brush, motor) | Very low |
| Overload withstand | Generally good | Depends on semiconductor design |
| Typical use | Precision loads, general supply | Fast-changing loads, abrupt fluctuations |
When to choose a servo regulator
- When output voltage must be held very precisely
- When voltage changes are slow and mostly long-lasting
- When overload withstand and robustness matter
- When one device is intended for a facility supply or machine group
When to choose a static regulator
- When voltage changes are sudden and frequent
- When brush and moving-part maintenance is undesirable
- In vibrating or mechanically harsh environments
- When silent operation is required
Is a combined solution possible?
Yes. Where both fast and precise correction are required, a fast static stage can be designed together with a servo stage that does the fine adjustment. This is more complex and costly, so it is recommended only when truly needed.
Questions to ask before deciding
- How fast and how often does grid voltage change?
- How sensitive is your load to small output deviations?
- What maintenance and service capability do you have?
- Does the environment involve vibration, dust or humidity?
- What are your budget and expected equipment life?
If the answers are unclear, a measurement log (voltage recorded over several days) shows the right way. To define the right choice for your project with our engineers, see our servo regulator and static regulator pages, or fill in the quote form.
Frequently Asked Questions
01What is the main difference between servo and static regulators?
A servo regulator corrects voltage steplessly and precisely with a servo-driven variac but more slowly. A static regulator corrects in steps with electronic switches, very fast and with no moving parts.
02Which is better for a CNC machine?
If output accuracy is the priority, servo is usually preferred; if voltage changes are very fast and abrupt, a static or combined solution is chosen. The final choice depends on measurements of the load and grid.
03Can servo and static regulators be used together?
Yes. Combined solutions can be designed that join a fast static stage with a precise servo stage.