A servo voltage stabilizer automatically corrects low or high incoming AC voltage within its operating range. It senses the output and drives a motor-operated regulating mechanism to bring it towards the selected voltage. To choose one, check the complete electrical load, supply phase and measured voltage at your site.
Why Voltage Regulation May Be Required
Electrical equipment is designed to operate within specified supply conditions. When incoming voltage repeatedly moves outside the range expected by a machine or electrical system, the equipment may trip, operate inconsistently or draw abnormal current depending on the type of load.
A stabilizer should not be selected simply because a machine has stopped or tripped. Wiring faults, loose connections, phase problems, machine protection settings and other electrical issues can produce similar symptoms. The incoming voltage should first be measured and the equipment fault information reviewed.
- Measure the actual minimum and maximum incoming voltage.
- Check whether the supply is single-phase or three-phase.
- Record the connected load or rated current.
- Identify motors, compressors or other high-starting-current loads.
How a Servo Voltage Stabilizer Works
A typical servo stabilizer continuously monitors the electrical supply through a control system. When the measured voltage moves away from the required level, the controller operates a motor-driven voltage-adjustment mechanism.
Many servo stabilizer designs use a variable autotransformer together with a buck-boost transformer. The variable autotransformer changes the corrective voltage, while the buck-boost section adds or subtracts that correction from the incoming supply. The exact internal arrangement, response and protection features vary by design.
Because the mechanism is automatic, the stabilizer continues adjusting while the supply is present. It does not, however, generate electricity or provide battery backup when the mains supply fails.
- Voltage sensing and control
- Servo-controlled adjustment
- Corrective voltage added or subtracted as required
- Continuous operation while mains supply is available
Single-Phase and Three-Phase Servo Stabilizers
The stabilizer phase must match the electrical supply and the equipment being connected. A single-phase load should not be treated as a three-phase load simply because a higher KVA is required.
KEVOR’s range covers 1–60 KVA single phase and 10–100 KVA three phase. Capacity pages cover listed options from 2 KVA to 100 KVA; choose phase and construction from the actual requirement.
Higher-capacity requirements such as 40 KVA, 50 KVA and 60 KVA single-phase or suitable three-phase configurations up to 100 KVA can be reviewed separately against the actual load, phase, cooling method, site-voltage range and application.
How the Input Voltage Range Is Selected
The input range should be based on voltage measured at the actual installation, not on a generic city value or only the nominal utility voltage.
Measurements should be taken safely at appropriate times, including when the normal load is operating and when the voltage problem is usually observed. For three-phase installations, the relevant phase measurements should be taken by a qualified electrician.
If the lowest measured voltage is substantially below nominal, a wider correction range may be needed. The final input and output configuration should be confirmed in the quotation or technical specification for the ordered unit.
Air-Cooled vs Oil-Cooled Servo Stabilizers
Cooling method is another important part of Servo selection. KEVOR can offer air-cooled and oil-cooled configurations, with availability confirmed for the selected model.
Check the offered design, running hours, ambient conditions and available ventilation together. Capacity alone does not determine the cooling method.
- Air cooling: model-specific construction
- Oil cooling: model-specific construction
- Final construction confirmed against technical requirement
Common Servo Stabilizer Applications
Servo stabilizers are commonly considered for industrial and commercial equipment where voltage variation has been confirmed and where the connected equipment benefits from regulated supply voltage.
The suitability of a stabilizer still depends on the equipment manufacturer requirements, load profile and actual electrical conditions.
- CNC and VMC machines
- Manufacturing and production equipment
- Packaging and automation machinery
- HVAC and refrigeration loads
- Laboratory and testing equipment
- Selected diagnostic or technical equipment where permitted by the equipment requirements
What to Share Before Asking for a Quote
A useful quotation starts with electrical information rather than only the requested KVA. If some values are not known, share the machine nameplate details and whatever site information is available.
- Machine or application
- Connected load in kW, HP, ampere or KVA
- Single-phase or three-phase supply
- Minimum and maximum incoming voltage
- Required output voltage if specified by the equipment
- Quantity and installation city