The Siemens 6SL3121-1TE21-0AA4 is a SINAMICS S120 Single Motor Module designated as a spare part, taking 600 V DC on the DC link and delivering 400 V three-phase AC at 9 A to the motor. The booksize format with external air cooling means it slots into a multi-axis cabinet alongside other S120 modules, sharing the DC bus and the centralized cooling airflow — not a standalone drive, but a modular axis component for a coordinated drive group. Rated for 9 A output, this module drives a motor sized roughly for that current at 400 V AC — think small conveyors, spindle drives, or auxiliary axes in a machine tool. The optimized pulse patterns reduce motor losses and audible noise at partial load, and the extended Safety Integrated functions (STO, SS1, SBC) let you wire the safety circuit directly to the module without a separate safety relay, saving panel space.
Integration note
Booksize modules mount side-by-side on a common mounting plate inside the S120 cabinet, with the external air cooling ducted through the heat sink. The DRIVE-CLiQ cable connects the Motor Module to the Control Unit or Line Module upstream — verify cable length and routing before panel layout, as the connector strain relief needs clearance.