The Siemens 3RK1322-0BS12-1AA1 is a SIRIUS AS-Interface compact reversing starter with solid-state motor protection and solid-state switching contacts. It is designed for reversing motor control in distributed automation architectures — think conveyor reversals, gate drives, or any application where you need to swap motor rotation without a separate contactor-and-overload assembly. Reversing starters are built with two contactors mechanically interlocked so both cannot close simultaneously; this one packages that function into a single IP65 enclosure ready for machine-mount or wall-mount deployment. Rated for 2.2 kW at AC-3 duty on a 400 V line, with a setting range of 2 to 5.95 A. The solid-state protection eliminates the thermal-lag issues of a bimetal relay, giving you faster, more repeatable overload response. The IP65 enclosure means the unit is dust-tight and protected against water jets from any direction. This is a washdown-ready package — suitable for food-and-bev lines, car washes, or any environment where hosing down the machine is part of the cleaning cycle. It is not submersible, but it will handle the spray.
AS-Interface integration and brake output
This starter communicates over AS-Interface (AS-i) protocol — the two-wire bus that carries both power and data on a single flat cable. It is not a PROFIBUS DP device; the AS-i interface is built in, so no external gateway module is required for the bus connection. The part includes bus communication capability as a standard function. A notable feature is the integrated motor brake output: a 24 V DC / 3 A contact for externally supplied brakes. If your motor has a spring-applied holding brake, this output switches it in sync with the motor power — brake release on start, brake apply on stop. That saves an external interposing relay and simplifies the wiring harness. The brake contact is rated for DC loads, so verify the brake coil current does not exceed 3 A. Main circuit connection uses tab terminals.
Breaking capacity and short-circuit coordination
The maximum short-circuit breaking capacity (Icu) at 400 V is rated at 100 000 A. That is a very high fault-current rating — it means this starter can safely interrupt a 100 kA fault without catastrophic failure, provided the upstream fuse (the design calls for fuse protection) is properly coordinated. For a line-side fault, the fuse clears the energy; the starter must withstand the let-through. This rating tells you the unit is suitable for installation close to large transformers or in high-fault-capacity industrial grids. The short-circuit protection design is fuse-based — no built-in magnetic trip. That means you must size the upstream fuse per the manufacturer's coordination tables. Do not assume a standard motor circuit protector (MCP) provides equivalent protection; the solid-state output stage has different fault-withstand characteristics than an electromechanical contactor.