Introducing SagFighter™ NanoPro – custom-configured for the semiconductor manufacturing industry.

Built on our proven SagFighter™ platform, UST’s new SagFighter NanoPro actively prevents unavoidable electrical issues from interrupting production, introducing errors and reducing chip yield.

NanoPro corrects utility-related and weather-related voltage sags within 2 milliseconds – before they can impact power-sensitive components or processes – allowing precision production to continue without interruption.


Request your detailed analysis of the actual and calculated performance of UST’s SagFighter across single-phase, two-phase and three-phase sags.

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SagFighter NanoPro Features

  • Custom-configured and optimized for the semiconductor fab industry
    • Ready to meet the challenges of 10nm, 7nm and beyond
    • 3 circuit breaker bypass arrangement – input, bypass and output – for ease of maintenance or service
    • Dry relay contacts for remote real time system status monitoring
    • Output power monitor metering with Mod-Bus/RS-45 communication: Power data collection through meter communication features (real time or historical data collection); Integration with building management systems
  • SEMI F47 compliant
  • Battery free and near-zero maintenance – no service/maintenance
    contracts needed
  • Full sag correction within 2 milliseconds
  • Sag correction duration independent of load or power factor
  • Sag correction for 100 seconds minimum
  • Robust industrial design – offering continuous protection for industrial
    loads (motors, production machinery, etc.), with no need for bypass
    operation even during adverse inrush (high current) conditions
  • Continuous protection without needing to recharge or reset
  • Non-continuous inverter operation that increases reliability and provides
    99% efficiency during normal operation

Operating without batteries or energy storage of any kind, the near-zero maintenance SagFighter monitors and corrects incoming voltage, greatly lowering the risk of production errors and downtime due to sags.

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.

Phase - Frequency (Hz)
Standard Input/Output Voltages 60Hz: 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 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 factory ]
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
MonitoringContacts for remote indication of unit and surge suppression status are included

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

UST SagFighterNXT™ Options
Frequecny: 50Hz5Required to identify 50 Hz units. Standard units are 60 Hz
Non-Standard EnclosureEStandard UST enclosure is a NEMA-1 indoor design. Custom indoor or outdoor enclosures are available based on end user specifications. Contact UST for further clarificaiton on specific enclosure design requirements.
Mechanical (Maintenance) BypassMThis option provides a "make-before-break" bypass to power the load while isolating & de-energizing the UST product for inspection or maintenance. The option requires a 3 circuit breaker arrangement (input, bypass, output ) with either mechanical or electrically operated circuit breakers. (size of the unit will determine circuit breaker design) NOTE: The SagFighter does have a bypass switch as standard which will remove the sag correction technology from the active circuit and send utility power to the load without monitoring for sag correction. When using the bypass switch, the SagFighter unit is not completely de-engergized.
Non-Standard VoltagesNStandard Voltages are 208V, 380V, 400V, 415V, 480V, 600V.
Wiring LabelsLCustom labeling and identification of unit wiring
Unidentified Options (custom)QOptions designed to meet specific customer requirements not considered standard by UST.