1000A High Speed thyristor protection AC Fuse.
NH (Blade) type in size DIN03.
Use with 830A 590P and 591P DC Thyristor Drives or double-up for use with 1580A rating.
Voltage rating is 690V AC maximum.
Manufacturer is Mersen, previously sold under the Ferraz Shawmut brand.
Parker SSD part number is CH590016