Have More Robust Surge Protective Devices with New Littlefuse LST Varistors

By Chad Cox

Embedded Computing Design

April 06, 2021


Have More Robust Surge Protective Devices with New Littlefuse LST Varistors

Littelfuse, Inc. introduced LST Varistor series.

Constructed with a proprietary thermally protected varistor technology (TMOV), this new varistor incorporates both a built-in thermal disconnect function and electric arc shield. This combination provides additional robust protection to prevent catastrophic failure and fire hazard even under the extreme circumstances of abnormal overvoltage conditions or varistor end-of-life.

It is specifically designed for Type 1 and Type 2 Surge Protective Devices (SPDs) used in markets and applications including:

  • Residential, Commercial, and Industrial buildings
  • Uninterruptable Power Supply (UPS)
  • Industrial motor control
  • Renewable energy
  • HVAC system

The LST Varistor series offer these key benefits:

  • Facilitate meeting UL1449 listed Type 1 or Type 2 standards by incorporating 200 kA SCCR, 20 kA In, UL1449 Type 4 recognized component assembly.
  • Flexibility of using 50 kA and 75 kA Imax rated devices with the same footprint on PCB.
  • More options for designing remote indication/monitoring of SPD product or system via mechanically triggered AC and DC rated microswitch (Normally Open/Normally Closed, pin length, 2 pin/3 pin/without pin).
  • Clear LST working status indication via a visual tab option that notifies service technicians and maintenance engineers to replace LST at end-of-life (EOL) to continue optimal surge protection for the end-product.
  • Wide Operating Voltage Range: Up to 690 Vac for 50 kA version, up to 550 Vac for 75 kA version.

For more information, visit littlefuse.com

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