The ABB 1SFA899311R6000 is a PSTP-5000/18 thyristor module rated 690V, designed as a replacement power stack for ABB PSTX series softstarters. It is a direct-fit thyristor assembly for the PSTX softstarter line — not a standalone starter, but the silicon switching stage inside one. If you are servicing a PSTX unit and the power section is open, this is the part that goes in.
Voltage rating and fit detail
The PSTP-5000/18 carries a 690V rating, which matches the line voltage range of the PSTX softstarter family it serves. That 690V class means it handles 400V and 480V systems with headroom, and is also suited for 690V nominal grids common in heavy industrial and mining installations. Suitable for PSTX — this is the OEM power thyristor module for that softstarter series. If you are rebuilding a PSTX unit, the form factor and bus-bar interface are specific to that enclosure; this is not a generic SCR pack.