Mersen A070UD32LI550 Protistor Fuse, 550A 700V AC, Size 32 aR, High-Speed Square Body with LI Bolted Contacts - Pack of 3

The Mersen Protistor® A070UD32LI550 (Item Number B219779) is a professional-grade, ultra-fast acting square body fuse-link engineered for the advanced protection of power semiconductor devices. With a rated current of 550A and a voltage rating of 700V AC, this Size 32 aR class fuse is designed for high-power electronics applications, including massive industrial rectifiers, AC/DC motor drives, and static transfer switches. It delivers superior current limitation and maintains low let-through energy (I²t) values to safeguard sensitive components such as IGBTs and thyristors during short-circuit events.

The A070UD32LI550 is manufactured with a high-strength ceramic body and silver-plated copper LI-style (Bolted Blade) contacts for optimized electrical contact and heat dissipation. The internal design utilizes pure silver elements combined with high-purity silica sand for effective arc quenching, enabling a high breaking capacity of 200kA. This model features an integrated Type K mechanical striker, which serves as a visual blown-fuse indicator and can be utilized with an auxiliary microswitch for remote fault detection.

Technical Specifications

• Manufacturer: Mersen
• Catalog Number: A070UD32LI550
• Item Number: B219779
• Amperage Rating: 550A
• Voltage Rating: 700V AC (IEC / UL)
• Interrupting Rating (Breaking Capacity): 200kA at 700V AC
• Operating Class: aR (Ultra-Fast Acting)
• Product Size: 32
• Mounting Configuration: LI (Bolted Blades)
• Indication System: Integrated Mechanical Striker (K-Type)
• Pre-arcing I²t: 64 kA²s
• Total Clearing I²t at Rated Voltage: 430 kA²s
• Power Dissipation at Rated Current: 90W
• Standards Compliance: IEC 60269-4, UL 248-13 Recognized, RoHS Compliant
• Quantity: Pack of 3