SLU-600 Universal Phase Monitoring Relay

The SLU-600 Universal Phase Monitoring Relay from the ATC Diversified Electronics division of Marsh Bellofram Corporation is a family of universal phase monitoring relays, designed to provide cost-effective protection from premature equipment failure or downtime caused by voltage faults or untimely outages on three-phase systems (Delta and Wye) up to 700 VAC.such as those typically found in motor control centers or other critical motor and pump monitoring applications. The SLU-600 Universal Phase Monitoring Relay unique rapid cycling feature prevents motors from cycling due to load-induced line fault conditions.



  • Monitors up to 700 VAC
  • Protects against:
    • Rapid cycling
    • Phase loss
    • Phase reversal
    • Phase unbalance
    • Phase shift
    • Over/under voltage
    • Over/under frequency
  • DIN-rail or surface mount
  • Operating range 200-700 VAC
  • Manual or automatic reset
  • Adjustable restart delay
  • Adjustable fault delay


  • Critical motor and pump monitoring
  • Water and wastewater plants
  • Sewage plants
  • Railroads
  • Booster stations
  • Grinders
  • Irrigation equipment
  • Petrochemical
  • Machine Tool
  • Conveyors
  • HVAC/R
  • Elevators/escalators
  • Utilities
  • Processing equipment
  • Agricultural machinery and equipment
  • Renewable energy – wind power turbine monitoring