The Siemens 3RK1322-0KS02-0AA3 is an AS-interface compact direct starter — a self-contained motor starting and protection unit that integrates the contactor, bimetal overload relay, short-circuit protection via circuit-breakers, and bus communication into a single IP65 enclosure. It is designed for distributed motor control in washdown or dusty environments where a central panel is impractical, and it communicates directly on the AS-interface bus (no PROFIBUS DP). The setting range of 0.9 to 1.25 A covers small three-phase motors up to 0.37 kW at 400 V AC-3 duty — typical for compact conveyors, agitators, or small pumps in food-and-beverage or material-handling lines. The IP65 rating means the entire unit, including the bus connection and motor outgoing feeder, withstands hose-down cleaning without a separate panel enclosure.
The AC-3 rated power of 0.37 kW at 400 V is the motor-switching capacity under typical starting conditions (up to 8× inrush). That is a firm ceiling — the bimetal overload is set between 0.9 and 1.25 A, so the motor full-load current must fall within that window. The unit includes a motor brake output (400 V AC) for motors with holding brakes — common on vertical-axis conveyors or gantries where the load must not drift on power loss. Two integrated inputs allow connection of local pushbuttons or sensors directly at the starter, reducing field wiring back to a PLC. The 9-pole motor outgoing feeder and 9-pole power connection are pre-wired at the factory — verify the pinout matches your motor cable assembly before installation.
Deployment context: distributed motor control in harsh environments
Because the starter is IP65 and communicates over AS-interface, it mounts directly on the machine frame or near the motor — no need for a local control cabinet. The 190 mm depth and 120 mm width are the envelope for the sealed housing; plan for clearance around the 9-pole connectors and cable bend radius.