What this AS-i compact reversing starter is
The Siemens 3RK1322-1FS02-1AA4 is an AS-interface compact reversing starter in an IP65 enclosure — a self-contained motor starting and reversing unit for distributed automation. It packs the contactor, reversing interlock, overload protection, and bus communication into one box you mount right on the machine frame, not back in the panel. Rated for motor loads up to 1.9 kW at AC-3 duty class at 400 V, with a setting range of 3.5...5 A via a bimetal overload relay. That AC-3 rating means it's designed for starting and stopping squirrel-cage induction motors under load — the kind of service you see on conveyors, pumps, and small fans out here in the grease. The IP65 rating means the whole assembly — contacts, bimetal, electronics — is sealed against dust and low-pressure water jets. You can mount this on a washdown station or a dusty conveyor line without a separate enclosure. It'll survive the route.
What the ratings mean for fit
The 1.9 kW at AC-3 400 V figure is the motor power this starter can handle under normal starting conditions — that's about a 3.5 to 5 A full-load motor current, which the bimetal range covers exactly. If your motor plate says 3.8 A FLA at 400 V, this unit lands right in the middle of its adjustment window. The 50 kA short-circuit breaking capacity at 400 V tells you this starter can safely clear a fault up to 50,000 A without welding its contacts or blowing apart. That's a high SCCR for a compact unit — it means you don't need a separate upstream fuse or breaker with a higher interrupt rating for most industrial distribution systems. Operating ambient spans -25 to +55 °C, which covers unheated warehouses and hot machine bays. The storage range goes wider, but that operating band is what governs real running conditions.
Bus integration and wiring
AS-interface protocol is built in — no separate gateway module needed. The starter communicates directly on the AS-i yellow cable, carrying start/stop, reversing commands, and feedback signals. PROFIBUS DP is not supported on this variant; if your network requires PROFIBUS, you'd need the DP version of this starter family. Main circuit connections use tab terminals (9-pole motor outgoing feeder and 9-pole power connection) — these are the standard flat-blade receptacles common on AS-i compact starters. The unit also includes two integrated inputs for local sensors (e.g., limit switches or emergency stops) that feed back through the AS-i network. A motor brake output is included onboard, rated for 500 V DC at 1 A. That's a separate circuit from the motor power — it switches a DC brake coil directly, saving you an external brake rectifier or relay.