Protect Critical Power Electronics with High-Speed Fuses
Littelfuse high-speed (semiconductor) fuses protect critical power electronics from overcurrents that may cause damage to your equipment. High-speed fuses are reliable, very fast-acting products that can reduce the amount of short circuit current and improve the life of your power semiconductor devices.





Introducing POWR-SPEED® Fuses!

How is POWR-SPEED® better? Backed by over 40 years of experience, Littelfuse engineered the POWR-SPEED® fuses with an innovative bridge design, arc-quenching material and a robust element to provide fast, extreme current limitation exactly where you need it.





Square Body PSR Series

POWR-SPEED® fuses specifically designed for protection of power semiconductor devices such as diodes, triacs, IGBTs, SCRs, MOSFETs and other solid state devices that are typically designed into power conversion and power conditioning equipment. Variable frequency drives, inverters, UPS, rectifiers and soft-starters are examples of typical equipment designed with sensitive power semiconductor devices that cannot withstand any line surge or overcurrent conditions and require high-speed protection.

Littelfuse POWR-SPEED® PSR Series products offer optimized circuit protection at the extremely fast speed required to protect modern day power conversion devices. Such products are commonly found in numerous applications including pulp and paper industries, cranes and heavy-lifting equipment, processing industries, wastewater treatment plants and various large factories and MRO facilities.


  • Best in Class DC performance
  • Extremely current limiting
  • Superior cycling capability
  • Global certification cURus, CCC, IEC
  • Direct bus-bar mount design
  • Visual and optional microswitch fuse blown indication
  • Low watt-loss design
  • Compliance with US and Canadian requirements
  • Class AR performance according to IEC60269-4

Round Body Series

Our new high-speed QS Series fuses have reduced the energy let-through by up to 70% over previous generation high-speed semiconductor fuses. Our experts have designed high-performance silver fuse elements that combine with a hardened silica filler to provide enhanced system protection.

POWR-SPEED® Fuses provide…

  • Reduced peak let-through current
  • Reduced energy let-through by 70%
  • Less energy wasted during operation
  • Arc-barrier technology
  • Laser-etched resistance values to eliminate labels that erode over time
  • Quick and easy field replacement
  • Better energy efficiency and impact protection levels


Fast-Acting High-Speed Fuses

Littelfuse High-Speed Fuses are designed to protect today’s equipment and systems, and are manufactured with Littelfuse-developed technology that sets tomorrow’s standards for accuracy, consistent quality, reliability, and predictable performance. These certified high-speed fuses are optimized for performance and efficiency to better protect your critical power semiconductors against short circuits.

  • Low Watt Losses
  • Controlled Transient Overvoltages
  • Extremely Current Limiting
  • UL Recognized

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POWR-Speed Product Catalog - Mandarin
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