Sourced and supplied by Al Imran Enterprises, Lahore, Pakistan. The Protistor PC32UD69V550TF - manufacturer reference L300068 - is a square-body high-speed semiconductor fuse link from the Ferraz Shawmut Protistor range, today manufactured under the Mersen brand. Rated 550 A at 690 VAC (IEC) / 700 V (UL) in characteristic aR for ultra-rapid protection, it is built to clear fault currents fast enough to protect power semiconductors in drives, inverters, rectifiers and UPS systems. This size-32 unit carries an integrated striker (the Q suffix in the type code) that trips a microswitch when the fuse operates, enabling remote alarm or interlock action. Metric-thread flush ends provide bolted connections into standard holders and busbars, and the design conforms to IEC 60269-4 with CE marking and cURus listing. Protistor URD-type links are specified wherever diode, thyristor, IGBT or GTO stacks need dependable short-circuit backup: variable frequency drives, DC drives, electrolysis and plating rectifiers, soft starters, inverters and uninterruptible power supplies. Al Imran Enterprises stocks genuine Mersen/Ferraz Shawmut semiconductor fuses in Lahore and supplies VFD manufacturers, panel builders and plant maintenance teams across Pakistan. Send us your drive rating or the marking from your old fuse and we will confirm the exact replacement, availability and delivery.