AS-i reversing starter for distributed motor control
The Siemens 3RK1322-0KS02-1AA4 is a SIRIUS AS-interface compact reversing starter — an electromechanical motor starter with integrated reversing contactors, bimetal overload protection, and AS-i bus communication, all in one IP65 enclosure rated for 0.37 kW at AC-3 duty on a 400 V supply. The setting range of 0.9 to 1.25 A means the bimetal overload relay is factory-matched to a narrow motor current window; you set the full-scale value to match the motor nameplate FLA within that band. IP65 protection lets this unit mount directly on a machine frame or conveyor section in washdown areas — no separate control cabinet needed for the motor branch.
What the ratings mean for fit
The 0.37 kW rating at AC-3 (400 V) defines the maximum three-phase induction motor this starter can switch under normal starting and running — a standard 0.37 kW (0.5 hp) motor at 400 V draws roughly 0.9–1.2 A, which sits inside the 0.9…1.25 A setting range. The 50 kA short-circuit breaking capacity (Icu) at 400 V means the integrated circuit-breaker-type short-circuit protection can safely interrupt a fault current up to 50 kA without upstream devices needing to clear it — important for high-fault-capacity industrial networks. The integrated motor brake output (500 V DC / 1 A per the description) controls a DC injection brake directly, saving an external brake contactor and simplifying the wiring harness for reversing applications that need rapid stopping.
AS-interface bus integration
AS-interface protocol (AS-i) is the fieldbus here — not PROFIBUS DP — so this starter communicates over a two-wire AS-i cable that carries both power and data to the reversing contactor coils and the two integrated inputs. The 9-pole motor outgoing feeder and 9-pole power connection (per the description) are tab terminals for the main current circuit, meaning the motor cable and AS-i drop connect via industry-standard tab receptacles — no screw terminals on the power side. Bus communication is enabled as a product function, so the starter reports status and accepts start/reverse/stop commands over the AS-i network without a separate I/O block.