The UST SagFighter™ MD active voltage conditioner protects sensitive medical equipment and pharmaceutical and other precision production processes from voltage sags.

Voltage sags caused by transmission line failures and weather-related disturbances are common everywhere in the world. SagFighter MD stands guard, ready to correct incoming voltage within 2 milliseconds, reducing to near zero the risk of sag-related equipment failures or production interruptions.

Key Features of the SagFighter MD

      • Overload protection, ideal for managing high in-rush applications common with medical scanning equipment
      • Full sag correction within 2 milliseconds
      • Battery free and near-zero maintenance – no service/maintenance
        contracts needed
      • 99% efficiency
      • Easy to install without interruption in services or production

The SagFighter™ active voltage conditioner continuously monitors the input voltage waveform for any deviation from a balanced, three-phase voltage. Upon sensing a deviation, the SagFighter engages an inverter circuit to apply an injection voltage to the primary windings of the series-connected transformer. The injection voltage is synthesized with a magnitude, shape, and phase angle so that when it is added in series with the incoming voltage, a balanced, three-phase voltage results. When normal, three-phase incoming voltage is detected at the SagFighter input, the inverter circuit is disengaged and the unit returns to monitoring mode.

The SagFighter is thermally ranged to provide continuous correction for a voltage sag, although this is not normally required.

The SagFighter uses natural convection cooling and has no fans or other moving parts. Larger units may include heat-sink fans that operate only when the unit is correcting a sag event. An automatic electronic failsafe bypass is incorporated into the standard design so the SagFighter maintains power to the load if a unit malfunctions.

The SagFighter automatically corrects voltage sags with no operator or programming required. The unit display provides unit status and historical information on sag correction events. Alarm contacts are also provided to permit remote indication of SagFighter status.

SagFighter installation is simple. The unit arrives completely assembled and requires no programming, testing, measuring or setting of switches. It is designed to install much like a dry-type transformer: simply place the unit and make input and output wiring connections. The SagFighter typically has no maintenance schedule other than routine inspection and cleaning.

Standard Input/Output 3-Phase Voltages60Hz: 208, 480, 600
50Hz: 220, 380, 400, 415

Regulation / Operating Characteristics
Sag Correction - Single Phase voltage event (sag)80% sag (20% remaining voltage) corrected to 95% of nominal voltage. 90% sag (10% remaining voltage) corrected to 90% of nominal voltage.
Sag Correction - 3- Phase voltage event (sag)40% sag (60% remaining voltage) corrected to 95% of nominal voltage. 42.5% sag (57.5% remaining voltage) corrected to 90% of nominal voltage.
Output RegulationRegulation tolerance is +/-5% (typical) (Note: SagFighter normally operates in monitoring mode until voltage reaches 90% of nominal voltage, at which time sag correction is initiated.)
Response TimeFull sag correction within 2ms regardless of load or load power factor.
Correction DurationSags corrected for a minimum of 100 seconds regardless of load or load power factor.
Regulation VariationNone - Regulation constant for 0 to 100% load and any load power factor.
Phase Shift CorrectionPhase shifts are corrected automatically during sag correction.
Harmonic DistortionNone added in monitoring mode.
Overload / Inrush Capability1,000% - 1 second, 500% - 5 seconds, 200% - 1 minute (while in bypass mode).
Load / Power Factor1 cycle typical regardless of load or load power factor.
Efficiency99% typical
Operating EnvironmentPerformance data specifications are based on the input (source) voltage meeting IEEE 519 standards.
Operating Frequency± 3% of nominal frequency (50Hz or 60Hz).

TechnologyMicroprocessor-controlled, inverter based series voltage injection.
TransformerCopper wound, dry-type series transformer (3W+G input and output).
Inverter OperationNon-continuous operation - activation only during sag correction.
CoolingNatural convection, w/ heatsink fans which operate only during sag correction [contaminant free, dry, clean air].
EnclosureFloor mounted NEMA-1 indoor enclosure is standard. ANSI 61 gray. [Custom enclosures (indoor or outdoor) also available - contact UST.]
Cabling / ConnectionsSee enclosure drawing for cable entry/exit options and input circuit breaker lug sizes.
Audible Sound LevelLess than 65dB @ 1 meter.
DisplayTouchscreen w/ event history recorder, operational data, and utilities.
ControlsAutomatic operation - no controls, programming, or user adjustments required.
MonitoringDry-contacts for remote indication of unit status are included as standard. Optional power metering with various communication protocols available - contact UST.

Environmental Requirements
Temperature - HumidityAmbient operating conditions: 32°F to 104°F (0 to 40°C) - Relative humidity 0-95% non- condensing
Operating Altitude0 to 3,300 ft. (1,000 M). Typical derating of 0.3% for every 100M over 1,000M