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Protective Relays

Current Relays

  • Description
  • Features
  • Applications
  • Ordering Info
  • Downloads
  • Accessories
  • CME420

    Digital current relay for AC systems

    The CME420 monitors for undercurrent and overcurrent in AC systems, as well as the current between two threshold values. True RMS values are read by the device. Current is displayed in real-time on the digital display. Trip values are explicitly set via the device's built-in menu. Two separate SPDT contacts are available, which can be set for normally energized or normally deenergized operation, latching or non-latching. An external supply voltage is utilized to power the device.

    When directly connecting the CME420 to the circuit, up to 16 A of current may be monitored. When connecting an X/5 type current transformer, the ratio of the CT may be entered into the device's settings. This allows explicit values to be entered and displayed of up to 999 A without any hand calculations required.

  • Key Features: CME420

    • Overcurrent and undercurrent monitoring in AC systems
    • Current monitoring between two threshold values
    • Current displayed in real-time on the digital display
    • Direct system connection for monitoring up to 16 A
    • Current transformer connection for monitoring up to 999 A
    • CT ratio entered into device allows for explicit value setting and display
    • 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 triggered alarm value stored in memory
    • Auxiliary supply voltage inputs
  • Applications: CME420

    • General applications requiring overcurrent and undercurrent protection
    • Generators, portable and fixed
    • Monitoring of industrial distribution systems
    • Motor overcurrent monitoring
  • Ordering information: CME420

    Name0...400 μA analog output0(4)...20 mA analog output0...10 V analog outputSPDT contact outputSupply VoltageOrdering Number
    CME420-D-12AC 16 - 72 V (42 - 460 Hz) DC 9.6 - 94 V B93060001
    CME420-D-22AC 70 - 300 V (42 - 460 Hz) DC 70 - 300 V B93060002
    CME420-DM-11AC 16 - 72 V (42 - 460 Hz) DC 9.6 - 94 V B93060003
    CME420-DM-21AC 70 - 300 V (42 - 460 Hz) DC 70 - 300 V B93060004
  • Downloads: CME420

    Document Name Language Date Download
    Technical Bulletin / Datasheet
    CME420
    English 03.2011
    Download
    Installation Bulletin
    CME420
    English 10.2012
    Download
    Menu Overview / Settings Checklist
    CME420
    English 08.2013
    Download
    User Manual
    CME420
    English 09.2006
    Download
    Brochure
    Overview of Products
    English 02.2014
    Download
    3D STEP Drawing
    420 Series (Standard)
    N/A 06.2013
    Download
  • Accessories: CME420

  • Description
  • Features
  • Applications
  • Ordering Info
  • Downloads
  • Accessories
  • CMD420

    Digital current relay for three-phase AC systems (1 A secondary CTs)

    The CMD420 monitors for overcurrent and/or undercurrent in three-phase AC systems. Current is measured as true RMS values. Values are shown in real-time on the device's LCD display. The current on each phase may be displayed independently by pressing the UP and DOWN buttons on the device. Each alarm type can be independently activated or deactivated based on the system requirements. Three separate time delays (startup, alarm response, and delay on release) allow the CMD420 to be tailored to specific applications. Two SPDT alarm contacts may be assigned any combination of alarms.

    Measurements are taken via external current transformers, one per phase. Alarm values are entered based on the secondary of the current transformer (0 - 1 A). Once the ratio is entered into the device, values shown on the display will be based on the primary of the current transformer - no mental calculations required. Ratios up to 2000:1 may be used with the device.

    The CMD420 uses x:1 type current transformers (1 A secondary). For use with current transformers with a 5 A secondary, see the CMD421.

  • Key Features: CMD420

    • Overcurrent and undercurrent monitoring in three-phase AC systems
    • Current monitoring between two threshold values
    • Current displayed in real-time on the digital display
    • Current transformer connection for monitoring up to 2000 A
    • CT ratio entered into device allows for explicit value setting and display
    • Onboard menu for settings
    • 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 triggered alarm value stored in memory
    • Auxiliary supply voltage inputs
  • Applications: CMD420

    • General applications requiring overcurrent and undercurrent protection
    • Generators, portable and fixed
    • Monitoring of industrial distribution systems
    • Motor overcurrent monitoring
  • Ordering information: CMD420

    NameSupply VoltageOrdering Number
    CMD420-D-1AC 16 - 72 V (42 - 460 Hz) DC 9.6 - 94 V B93060006
    CMD420-D-2AC 70 - 300 V (42 - 460 Hz) DC 70 - 300 V B93060007
  • Downloads: CMD420

    Document Name Language Date Download
    Technical Bulletin / Datasheet
    CMD420 / CMD421
    English 01.2013
    Download
    Installation Bulletin
    CMD420 / CMD421
    English 01.2013
    Download
    Menu Overview / Settings Checklist
    CMD420 / CMD421
    English 08.2013
    Download
    User Manual
    CMD420 / CMD421
    English 08.2012
    Download
    Brochure
    Overview of Products
    English 02.2014
    Download
    3D STEP Drawing
    420 Series (Standard)
    N/A 06.2013
    Download
  • Accessories: CMD420

  • Description
  • Features
  • Applications
  • Ordering Info
  • Downloads
  • Accessories
  • CMD421

    Digital current relay for three-phase AC systems (5 A secondary CTs)

    The CMD421 monitors for overcurrent and/or undercurrent in three-phase AC systems. Current is measured as true RMS values. Values are shown in real-time on the device's LCD display. The current on each phase may be displayed independently by pressing the UP and DOWN buttons on the device. Each alarm type can be independently activated or deactivated based on the system requirements. Three separate time delays (startup, alarm response, and delay on release) allow the CMD421 to be tailored to specific applications. Two SPDT alarm contacts may be assigned any combination of alarms.

    Measurements are taken via external current transformers, one per phase. Alarm values are entered based on the secondary of the current transformer (0 - 5 A). Once the ratio is entered into the device, values shown on the display will be based on the primary of the current transformer - no mental calculations required. Ratios up to 2000:5 may be used with the device.

    The CMD421 uses x:5 type current transformers (5 A secondary). For use with current transformers with a 1 A secondary, see the CMD420.

  • Key Features: CMD421

    • Overcurrent and undercurrent monitoring in three-phase AC systems
    • Current monitoring between two threshold values
    • Current displayed in real-time on the digital display
    • Current transformer connection for monitoring up to 2000 A
    • CT ratio entered into device allows for explicit value setting and display
    • Onboard menu for settings
    • 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 triggered alarm value stored in memory
    • Auxiliary supply voltage inputs
  • Applications: CMD421

    • General applications requiring overcurrent and undercurrent protection
    • Generators, portable and fixed
    • Monitoring of industrial distribution systems
    • Motor overcurrent monitoring
  • Ordering information: CMD421

    NameSupply VoltageOrdering Number
    CMD421-D-1AC 16 - 72 V (42 - 460 Hz) DC 9.6 - 94 V B93060008
    CMD421-D-2AC 70 - 300 V (42 - 460 Hz) DC 70 - 300 V B93060009
  • Downloads: CMD421

    Document Name Language Date Download
    Technical Bulletin / Datasheet
    CMD420 / CMD421
    English 01.2013
    Download
    Installation Bulletin
    CMD420 / CMD421
    English 01.2013
    Download
    Menu Overview / Settings Checklist
    CMD420 / CMD421
    English 08.2013
    Download
    User Manual
    CMD420 / CMD421
    English 08.2012
    Download
    Brochure
    Overview of Products
    English 02.2014
    Download
    3D STEP Drawing
    420 Series (Standard)
    N/A 06.2013
    Download
  • Accessories: CMD421