The Siemens 6SL3121-1TE21-0AA3 is a SINAMICS S120 Single Motor Module in the booksize format, fed from a 600 V DC link and delivering 400 V three-phase AC at 9 A to a motor. It is listed as a spare part, meaning it is a direct replacement for an existing module in a live S120 drive system — not a new-design-in part for a fresh panel. The module supports optimized pulse patterns and extended Safety Integrated functions, and ships with a DRIVE-CLiQ cable for the motion-control bus.
The lifecycle stage is marked mature, which means the design is stable and the part remains in the Siemens catalog, but it is not a current new-development target.
The 600 V DC input means it connects to a common DC bus from a Smart Line Module or Basic Line Module; verify the bus voltage range and pre-charge circuit before swapping a module live. The DRIVE-CLiQ cable is included, so you do not need to order it separately for a one-for-one swap, but check the cable length against your cabinet layout — the module expects a direct connection to the Control Unit or another DRIVE-CLiQ node.