What it is and what it does
The Siemens 3RK1322-1KS02-1AA3 is an AS-Interface compact reversing starter — an electromechanical motor starter with bimetal overload protection, designed for reversing duty on three-phase motors up to 5.5 kW at 400 V AC-3. The setting range spans 9 to 12 A, adjusted via the bimetal relay. It includes a motor brake output, two integrated inputs, and communicates over AS-Interface (not PROFIBUS DP). The IP65 enclosure means the entire assembly — starter, bus interface, and connections — is rated for washdown environments, so it mounts directly on the machine frame or conveyor line without a separate control cabinet.
Key ratings and what they mean for fit
The 5.5 kW AC-3 rating at 400 V defines the maximum induction motor it can switch under typical starting conditions — think small conveyors, pumps, or fans. The 9-12 A setting range on the bimetal overload matches motors drawing full-load current in that band; if your motor nameplate FLA is 10.5 A, this starter lands right in the middle of the adjustment window. The 50 kA short-circuit breaking capacity at 400 V means it can safely interrupt a fault current up to that level without upstream fuses or breakers needing to clear first — important for high-fault-capacity installations. Operating temperature from -25 to +55 °C covers most indoor and sheltered outdoor installations, though direct sunlight on the black enclosure may push internal temperatures higher.
Integration and mounting
This is a self-contained unit — no DIN rail required, no separate contactor and overload to wire. The IP65 housing (270 x 120 x 190 mm) has tab terminals for the main circuit and a 9-pole motor outgoing feeder plus a 9-pole power connection. The AS-Interface bus cable daisy-chains through the unit, and the two integrated inputs can take signals from pushbuttons or sensors directly, reducing junction box wiring. The brake output is a separate contact rated for the motor brake coil, so you don't need an extra interposing relay for holding-brake applications.