What it is and what it does
The Siemens 3RK1322-1KS02-0AA4 is an AS-interface compact starter — a self-contained direct-on-line (DOL) motor starter in an IP65 enclosure meant for mounting out on the machine frame, not back in the panel. It's a direct starter with electromechanical switching contacts and bimetal motor protection, rated for a setting range of 9…12 A. At AC-3 duty on 400 V it delivers 5.5 kW, which means it handles standard three-phase induction motors up to that load — pumps, fans, conveyors — right where the motor sits. The IP65 rating means the whole unit — housing and connections — stands up to hose-down and dust ingress, so you can mount it on the machine frame in washdown areas or dusty environments without a separate cabinet. It communicates over AS-interface (AS-i), so it drops onto a two-wire bus for both power and data, cutting the point-to-point wiring back to the PLC. A built-in motor brake output (500 V DC / 1 A) handles the holding brake on vertical-axis motors or conveyors that need to lock on power loss.
Key ratings and what they mean for fit
The 5.5 kW rating at AC-3 (400 V) is the motor switching duty — that's the figure that governs whether this starter can handle your motor's starting and stopping under load. AC-3 covers starting and plugging/plugging-stop of squirrel-cage motors; if your motor nameplate says 5.5 kW or less at 400 V, this starter is sized for it. The setting range of 9…12 A on the bimetal overload matches the full-load current of a 5.5 kW motor at 400 V (roughly 11 A), so you dial the overload relay to the motor's FLA. The maximum short-circuit breaking capacity (Icu) at 400 V is 50,000 A — that's the fault current this unit can safely interrupt without blowing apart. If your panel's available fault current is under 50 kA at 400 V, this starter coordinates with upstream circuit-breakers (the design uses circuit-breakers for short-circuit protection per). That's a real number for selectivity studies. Ambient temperature range of -25…+55 °C during operation covers most industrial floors, but if you're mounting it near a hot motor or in a sun-baked enclosure, keep the upper end in mind — the bimetal trip curve shifts with ambient, so derate if you're running at the top of the range.
Where it goes and how it connects
This compact starter is designed for machine-mounting, not DIN-rail inside a panel. The IP65 enclosure and tab terminals for the main current circuit mean you run motor cables directly to the unit with ring or fork terminals. The 9-pole motor outgoing feeder and 9-pole power connection handle the motor leads plus the AS-i bus and brake wiring — you're looking at a single cable entry for the motor, one for the bus, and the brake wires. Dimensions are 190 mm deep, 120 mm wide, 270 mm tall — about the size of a shoebox on its side — so plan the gland plate or bracket accordingly. It integrates into an AS-interface network directly — no PROFIBUS DP on this variant (says no). The two-wire AS-i bus carries both power and communication, so you run a single yellow cable from the AS-i power supply/gateway to the starter. The two integrated inputs let you connect limit switches or pushbuttons local to the motor without a separate I/O block.