Voltage regulation
Servo Controllers
Control cards that sense voltage and drive the servo motor in a stabilizer.
- Sensing
- Single or three phase
- Motor drive
- Raise / lower output
- Format
- Card for a host enclosure
Have a different requirement? Share your application and preferred configuration.
Made for the application.
A servo controller compares the stabilizer output with its set point and commands the servo motor to raise or lower the variable transformer. It also carries the voltage trips and time delays that protect the load. Invitrona supplies single-phase and three-phase controller cards for mounting inside a host stabilizer enclosure, with the sensing range and motor drive matched to the host equipment.
Typical application contexts
- New servo voltage stabilizer assemblies
- Replacement controllers for installed stabilizers
- Stabilizer manufacturers and panel builders
- Service and refurbishment of regulation equipment
Sensing and drive on one card
The card measures the output, compares it with the set point and drives the servo motor in one assembly.
Adjustable set point and dead band
Set point, dead band and time delays are adjusted at commissioning to suit the stabilizer and its motor.
Load protection trips
Under-voltage, over-voltage and single-phasing trips open the stabilizer output contactor through a relay output.
Matched to the host
Sensing range, motor drive and terminal assignment are documented against the host stabilizer before supply.
Technical specifications
Typical values for the product class. The ratings, options and operating conditions for your equipment are confirmed during engineering review and stated in the quotation.
| Parameter | Value | Condition |
|---|---|---|
| Rating range | For host stabilizers up to 500 kVA | The card rating follows the motor and sensing interface, not the stabilizer kVA |
| Auxiliary supply | 230 V AC, typically 180–260 V AC | Taken from the stabilizer output or a control transformer |
| Sensing range | Typically 300–480 V AC three phase or 150–270 V AC single phase | Phase-to-phase or phase-to-neutral as specified |
| Set point adjustment | Typically ±10% of nominal output | Adjusted at commissioning |
| Regulation accuracy | Typically ±1% of set point | With a correctly sized stabilizer and servo drive |
| Dead band | Adjustable, typically 1–3% of set point | Set to avoid motor hunting |
| Motor drive output | Raise and lower relay or solid-state outputs for 230 V AC or 24 V DC servo motors | Contact rating stated for each card |
| Protection functions | Under-voltage and over-voltage trip with time delay; single-phasing trip; motor limit inputs | Thresholds adjustable; relay output to the stabilizer contactor |
| Indication | LED status for supply, raise, lower and trip | Digital display by assessment |
| Ambient temperature | 0–50 °C | Inside a ventilated host enclosure |
| Mounting | Open card on stand-offs inside the host enclosure | Conformal coating by assessment |
| Connections | Plug-in or screw terminal blocks | Terminal assignment documented with the host wiring |
Documents & next steps
PDFServo Controllers datasheetTypical specifications · For stabilizers up to 500 kVADrawings and documents for a specific order are agreed during engineering review.
For a useful first conversation
- Host stabilizer rating, phases and control arrangement
- Servo motor type, supply and limit-switch arrangement
- Sensing range, protection thresholds and indication needs
- Integration, validation and change-control responsibilities
Common questions
A little context before you enquire.
Can a servo controller replace the card in an existing stabilizer?
Often, provided the sensing range, motor type and terminal assignment match. Share the stabilizer rating, the motor details and a photograph of the existing wiring for review.
Is the servo controller sold as a complete stabilizer?
No. The controller is a card that mounts inside a host stabilizer. Complete units are listed under Servo Voltage Stabilizers.
Why does the dead band matter?
If the dead band is too narrow the motor hunts back and forth; if it is too wide the output drifts further before correction. It is set at commissioning for the host stabilizer.
Which motor types can the card drive?
Cards are configured for the servo motor fitted to the host stabilizer, typically a 230 V AC or 24 V DC motor. The motor details are confirmed before supply.
Where it is used
Application pathways that commonly start with this product class.
- IndustrialProduction facilities and process equipment
- OEM & product integrationPower designed into your equipment
