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  • VMD420

    Digital voltage and frequency relay for three-phase AC systems

    The VMD420 is a powerful, all-in-one unit for monitoring three-phase AC systems up to 500 V. The VMD420 is capable of monitoring for overvoltage and undervoltage, overfrequency and underfrequency, asymmetry, phase sequence, and phase loss. Values are displayed and changed via a digital seven-segment display and menu. Values are displayed as true RMS values, and many different delays can be set.

    The VMD420 unit utilizes an auxiliary supply voltage for power. For the version that is powered off of the monitored line, please see the VMD421H.

  • Key Features: VMD420

    • Overvoltage, undervoltage, overfrequency, and underfrequency, asymmetry, phase sequence, and phase loss monitoring for three-phase AC systems
    • True RMS readings
    • Digital display with values shown in real-time
    • Separately adjustable alarms for each alarm type
    • Onboard menu for settings; explicit trip values can be entered in
    • Two SPDT contact outputs, independently configurable to any combination of alarm types
    • Separately adjustable time delays for response delay, startup delay, and delay on release
    • Built-in test and reset buttons
    • Latching or non-latching operation, selectable
    • Normally energized or normally de-energized operation, selectable
    • Last tripped alarm value stored in memory
    • Auxiliary supply voltage inputs
  • Applications: VMD420

    • General applications requiring overvoltage / undervoltage protection
    • Generators, portable and fixed
    • Monitoring of industrial distribution systems
    • Motor overvoltage and phase loss protection
  • Ordering information: VMD420

    NameSystem Voltage0...400 μA analog output0(4)...20 mA analog output0...10 V analog outputSPDT contact outputSupply VoltageOrdering Number
    VMD420-D-1AC 0 - 500 V (15 - 460 Hz) 2AC 16 - 72 V (42 - 460 Hz) DC 9.6 - 94 V B93010005
    VMD20-D-2AC 0 - 500 V (15 - 460 Hz) 2AC 70 - 300 V (42 - 460 Hz) DC 70 - 300 V B93010006
    VMD420-DM-1AC 0 - 500 V (15 - 460 Hz) 1AC 16 - 72 V (42 - 460 Hz) DC 9.6 - 94 V B93010017
    VMD420-DM-2AC 0 - 500 V (15 - 460 Hz) 1AC 70 - 300 V (42 - 460 Hz) DC 70 - 300 V B93010018
  • Downloads: VMD420

    Document Name Language Date Download
    Technical Bulletin / Datasheet
    VMD420
    English 04.2011
    Download
    Installation Bulletin
    VMD420
    English 10.2012
    Download
    Menu Overview / Settings Checklist
    VMD420
    English 08.2013
    Download
    User Manual
    VMD420
    English 01.2010
    Download
    Brochure
    Overview of Products
    English 06.2017
    Download
    3D STEP Drawing
    420 Series (Standard)
    N/A 06.2013
    Download
  • Accessories: VMD420