UST Current BalancerContinuous Protection for Submersible Water Pumps

Water supply systems across the country play a vital role in protecting the quality of life in rural areas and small municipalities by providing safe and affordable drinking water. Often, because of their remote location, unstable power can compromise the operation and productivity of a water pumping station.

Reduce Downtime and Improve Efficiency

The UST Current Balancer protects pumps from harmful overheating and vibration caused by unequal incoming phase-to-phase voltage that can shorten motor life up to 75%. Our Current Balancer automatically provides continuous balanced current to keep motors operating within OEM recommended specifications.


  • Save thousands of dollars in replacement pump costs
  • Avoid critical downtime and unscheduled maintenance
  • Improve motor efficiency, save energy, and prolong the life of the pump motor
  • Automatically adjust current with no power-factor limitations
  • The proven solid state design with ultra high speed correcting characteristics means no scheduled maintenance
  • No controls to adjust or instruments to read. The Current Balancer is pre-programmed from the factory designed for “plug & play” installation
  • Very low operational cost with a 99% efficient design

The Current Balancer is the right solution for those who are responsible for providing continuous, safe and affordable water to homes and communities in rural settings by enhancing the overall reliability of the water system.

See article: UST Current Balancers Keep Water Flowing in Rural Texas.

Power Rating/Size (kVA) Up to 250kVA (larger sizes available upon request)
Phase - Frequency (Hz) 3 phase 60Hz or 50Hz  
Voltage (L-L) 480V (typical), any industry standard 3-phase voltage available.
Connections Input: Wye (3W+N+G) or Delta (3W+G).    Output:  Delta (3W+G)
Cable Entry Side, Rear lower
Regulation/Operating Characteristics
Input Voltage Range Nominal +/-10% with 5% or less phase to phase voltage unbalance
Output Current Balance 3% phase to phase, or less (Typical) for the specified input voltage range
Current Balance vs. Load Current balancing is the same across the load and power factor range
Overload / Inrush Capability 1000% - 1 second, 500% - 5 seconds, 200% - 1 min. ; 1000% fault clearing
Minimum Load Current balance requires minimum 10% load. Unit will run any load from 0% to 100% rated.
Load Power Factor No minimum or part load or load power factor limitations, compatible with all load types
Tap Switching No load current interruption or waveform distortion on switching at any load or power factor
Zero Crossing Sensitivity Tap switching not dependent on determining load current zero crossing
Harmonic Distortion No distortion added at any load or power factor
Balance Correction Time Less than 5 seconds typical (manual adjustment provided)
Efficiency 99% typical
Operating Frequency ±3% of nominal frequency
Noise Suppression/Load Protection
Surge Suppression Included, complies with ANSI/IEEE C62.41, UL 1449
Failsafe Electronic Bypass Auto-actuation on high temperature, over-current, component failure with no loss of load
Technology Electronically-controlled tap switching series transformer design
Switching Semiconductors Non-full power semiconductors – individual SCRs are not required to carry full unit current
Controls Microprocessor-based control
Cooling NEMA-3R (outdoor) with thermostatically controlled fan/s.
Transformer Copper wound, meets ANSI specs
Enclosure NEMA 3R, Outdoor (std. Enclosure 36”W x 22”D x 57” H, up to 125kVA, larger sizes available)
Backlit LCD Display Displays tap position and correction by phase
Power Monitor / Meter Available as option for voltage & current display
Environmental Requirements
Temperature - Humidity Ambient 32 to 104°F (0 to 40°C) – Relative humidity 0-95% non-condensing
Audible Sound Level Meets or exceeds NEMA standards
Operating Altitude 0 to 3,300 ft (1000m)