The Siemens 3RK1322-1ES02-1AA3 is a SIRIUS AS-i compact reversing starter — an electromechanical motor starter with integrated reversing contactors, bimetal overload protection, and short-circuit protection via circuit-breakers, all in one IP65 enclosure. It's built for distributed motor control on AS-interface networks, meaning you run the motor forward and reverse without a separate control cabinet. The 1.5 kW rating at 400 V AC-3 tells you it's sized for a standard 2 HP induction motor on a conveyor or pump — the AC-3 duty class covers starting and stopping squirrel-cage motors under load, which is the real-world use case. The setting range of 2.8 to 4 A matches the full-load current of that motor size.
What the ratings mean for fit
The 50 kA short-circuit breaking capacity (Icu) at 400 V means this starter can safely interrupt a fault current up to that level without blowing up upstream — that's a high-fault rating for a compact unit, so it's fine on most industrial distribution panels without needing a current-limiting fuse ahead of it. The IP65 rating means the whole assembly — contacts, overload, bus electronics — is sealed against dust and low-pressure water jets, so it mounts directly on the machine frame or conveyor line in washdown areas. Operating temperature from -25 to +55 °C covers unheated warehouse floors and hot motor bays alike.
AS-interface and brake integration
This unit communicates over AS-interface (AS-i), not PROFIBUS DP — the bus protocol is AS-i, which is a two-wire network carrying both power and data for sensors and actuators. That makes it a drop-in for AS-i lines where you want reversing control plus feedback without pulling separate control cables. It also includes a motor brake output (400 V AC), so if your motor has an electromagnetic brake for holding a vertical load, the starter handles the brake coil timing directly — one less relay to add.
Panel and mounting considerations
The enclosure measures 270 mm high, 120 mm wide, and 190 mm deep — that's a compact footprint for a reversing starter with bus electronics and brake contact. It uses tab terminals for the main current circuit, so you'll need mating fast-on connectors rather than screw terminals. The IP65 housing means it's surface-mount on a machine frame or wall bracket, not DIN-rail inside a cabinet — plan for gland-plate entry for the AS-i cable and motor leads.