The Siemens 3RK1322-0AS12-1AA3 is an AS-Interface compact reversing starter in an IP65-rated enclosure, designed for distributed motor control right at the machine — no separate control cabinet needed for the motor branch. It uses solid-state motor protection and solid-state switching contacts, so there are no moving parts to wear in the power path. The setting range covers 0.6 A to 2.18 A, which translates to a motor power range of 0.18 kW to 0.8 kW at AC-3 duty on a 400 V supply. That AC-3 rating means it handles starting and stopping of squirrel-cage induction motors under load — the typical conveyor, pump, or fan application. The IP65 rating means the housing is dust-tight and protected against water jets from any direction. This starter mounts directly on the machine frame or a bracket in washdown zones — food processing, packaging lines, or any area where hose-down cleaning is routine. The enclosure carries the motor protection logic and the reversing contactors in one package, so you save a DIN-rail row in the panel.
AS-Interface integration and brake control
This starter communicates via AS-Interface protocol, not PROFIBUS DP. That means it connects to the AS-i yellow cable with a single two-wire drop — no shielded multi-core back to the PLC cabinet. The part includes bus communication capability and two integrated inputs, so you can wire limit switches or pushbuttons directly into the starter without a separate I/O block. It also has a motor brake output for internally supplied brakes at 400 V AC, which is common for holding brakes on vertical-axis motors or conveyors that must lock when power is removed. The main circuit connects via tab terminals — a standard fast-on connection that mates with the AS-i power tap or a pre-wired harness. The 9-pole power connection handles the motor leads, brake wiring, and the AS-i bus in one plug. For a commissioning engineer, the key check is that the AS-i master is configured for a slave with two inputs and one output (the reversing contactor command).
Short-circuit protection and breaking capacity
Short-circuit protection is by external fuse — the starter itself does not contain a magnetic or thermal-magnetic breaker. The maximum short-circuit breaking capacity (Icu) at 400 V is rated at 100 kA. For a panel OEM or site engineer, this means the fuse selection is not arbitrary: the fuse must clear a 100 kA prospective fault current while limiting the let-through energy to what the solid-state output can withstand.