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Littelfuse VM800 3-Phase Voltage Monitoring Relay

Littelfuse VM800 3-Phase Voltage Monitoring Relay protects 3- and 4-wire motors ranging from 145VAC to 500VAC, regardless of their size. This relay features an LCD screen with a green backlight, providing real-time monitoring, fault visibility, and the ability to review the last five faults. This relay monitors various detections, including undervoltage, overvoltage, frequency drift, phase sequence, phase loss, and neutral failure. Littelfuse VM800 Monitoring Relay is suitable for building systems, refrigeration, cooling, water and waste, and industrial machines.

Features

  • LCD screen with green backlight
  • Configurable trip and restart delays
  • Multi-voltage at 145VAC 500VAC
    • 3 phase, 4 wire
    • 3 phase, 3 wire
  • Improved accuracy and high reliability
  • Clear indication of trip status
  • Adjustable on/off time delay in seconds/minutes
  • 5A single and dual relay outputs
  • 2 separate relay outputs with independent programming
  • Password protection
  • Log of 5 previous faults for better monitoring
  • Fail-safe/non-fail-safe relay output

Applications

  • Water and waste
    • Irrigation pumps
    • Lift stations
    • Cooling towers
    • Automation panels
  • Refrigeration and cooling
    • Rooftop ACs
    • Supermarket systems
  • Building systems
    • HVAC compressors
    • Lifts
    • Escalators
  • Industrial machines
    • Conveyors
    • CNCs
    • Packaging lines

Specifications

  • 145VAC to 500VAC supply voltage
  • 45Hz to 65Hz frequency range
  • <6VA power consumption
  • 5A contact rating
  • 2% to 50% phase asymmetry
  • 36mm x 90mm x 66.2mm dimensions
  • UL 94V-0 rated enclosure
  • IP20 protection for enclosure and terminals
  • IP40 protection for the dust cover
  • IEC 60255-1 standard
  • -10°C to +60°C operating temperature range

Dimensions

Mechanical Drawing - Littelfuse VM800 3-Phase Voltage Monitoring Relay
Published: 2025-09-29 | Updated: 2025-11-13