The Siemens 6SL3357-3AG38-1AA7 is a factory-spare Interface & Protection (IPD) card for the SINAMICS S120 water-cooled (CuNi) Active Line Module rated at 900 kW. It handles the gate-drive and protection logic between the control unit and the line-side IGBTs, so if the module throws a comms fault or a gate-drive error, this is the board that gets swapped. The card operates on a 750-1035 V DC link and is sized for 907 A continuous — that matches the 900 kW module's full output. Group code R2SC and product group 4Q30 are the Siemens internal tracking codes; quote them on any cross-reference request to avoid the wrong revision.
What to verify before ordering
This is the IPD board only — no power section, no control unit. The mating connector pinout is fixed for the CuNi water-cooled module; confirm the module frame size and revision against your existing nameplate before committing the PO. The 907 A rating is the board's current-sensing and protection threshold, not the module's output current — the module itself is 900 kW. Packaged singly. No special handling beyond standard ESD precautions for a populated PCB. If you are replacing a failed board on a live line, have the module's firmware version handy — the IPD card does not carry the firmware, but the control unit may need a matching software release to recognize the new board revision.