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Littelfuse SMOV Thermally Protected Varistors w/ Micro-Switch

Littelfuse SMOV Thermally Protected Varistors with the micro-switch indicator to help designers meet the requirements specified in UL1449 (3rd edition) for Type 1 or Type 2 Surge Protection Device (SPDs) applications. SMOV Varistors safely disconnect from the circuit in a sustained overvoltage, intermediate current condition as defined by UL1449 (3rd edition). The integrated thermal element is positioned close to the MOV body to allow for a quick thermal response. 

These varistors offer high peak surge current handling and energy absorption capabilities with an operating voltage range compatible with common AC line voltage (115VAC to 750VAC). A separate micro-switch indicates when the MOV has been disconnected from the circuit. This separate switch isolates the monitoring circuitry from the primary circuit to ensure indicator circuit safety and simplify the user's circuit design.

Littelfuse SMOV Series Thermally Protected Varistors are especially well-suited for surge-protection devices, AC-panel protection modules, power transfer switches, AC/DC power distribution systems, photovoltaic systems, and cell phone base stations.

Features

  • High peak surge current handling capability
  • High energy absorption capability 
  • Standard operating voltage range compatible with common AC line voltage (115VAC to 750VAC)
  • Provides high peak surge current rating (up to 40kA)
  • 25mm2 (SMOV25) or 34mm2 (SMOV34) varistor
    • Integrated thermal disconnect designed to open in the event of overheating due to abnormal overvoltage (3rd edition of UL1449)

Applications

  • Surge-protection devices
  • AC-panel protection modules
  • Power transfer switches
  • AC/DC power distribution systems
  • Photovoltaic systems
  • Cell phone base stations

Specifications

  • 20kA, 8/20 waveshape (SMOV25); 40kA, 8/20 waveshape (SMOV34) maximum single surge capability
  • 10kA (SMOV25) and 20kA (SMOV34) nominal discharge current value
  • 50A/150A intermediate current rating
  • -45°C to +75°C operating temperature
  • Recognized to UL 1449 3rd edition
  • Lead free
  • RoHS compliant
Published: 2012-05-23 | Updated: 2022-03-11