What this part is and where it fits
The Siemens 3RK1322-1FS02-1AA3 is an AS-interface compact reversing starter in an IP65-rated enclosure, designed for direct-on-line motor control in distributed automation layouts. It's an electromechanical reversing starter with bimetal motor protection, set for a current range of 3.5 to 5 A, delivering 1.9 kW at 400 V under AC-3 duty — that's the motor-switching rating, not the resistive load curve. The IP65 rating means the housing and connections withstand washdown environments, so this lands on machine-mounted or conveyor-line installations where a central panel isn't practical.
Key ratings and what they mean for fit
The 3.5 to 5 A setting range and 1.9 kW at 400 V AC-3 tell you this is sized for small three-phase motors — think fractional to about 2.5 HP at 400 V. The bimetal overload relay inside provides inverse-time thermal protection, so it tracks motor heating reasonably well for standard squirrel-cage induction motors. The 50 kA breaking capacity at 400 V (Icu) means it can safely interrupt a fault current up to that level without welding contacts or cascading upstream — that's a strong SCCR for a compact starter, and it simplifies coordination in a distribution board.
AS-interface and bus integration
This starter communicates via AS-interface protocol, not PROFIBUS DP. That's a key distinction: AS-i is a two-wire bus that carries both power and data to the device, so you don't need a separate control cable for the coil. The part includes bus communication capability and two integrated inputs, which means it can take direct commands from the AS-i master and also read local sensors (e.g., limit switches or presence detectors) without an extra I/O block. There's also a motor brake output built in — a 400 V AC brake contact for holding brakes on vertical-axis drives.
Physical layout and connection
The enclosure measures 270 mm high, 120 mm wide, and 190 mm deep — a compact footprint for a reversing starter with integrated bus and brake output. Main circuit connections use tab terminals, which are common for quick-connect wiring in distributed installations. The motor outgoing feeder is a 9-pole connection, and the power connection is also 9-pole, so you're wiring a single multi-conductor cable for the motor, brake, and feedback. Operating temperature range is -25 to +55 °C, which covers most factory-floor conditions short of foundry or freezer applications.