What it is and where it fits
The Siemens 3RK1322-0HS02-0AA3 is an AS-i compact direct starter — a self-contained motor starting and protection unit in an IP65 enclosure, rated for 0.55 to 0.8 A with a motor power of 0.21 kW at 400 V AC-3 duty. It uses a bimetal overload relay for motor protection and integrates a brake contact output, making it suited for conveyors or small drives that need a controlled stop. The IP65 rating means the housing and connections withstand washdown environments — food processing, packaging lines, or outdoor conveyor sections where dust and hose-down are routine.
Key ratings and what they mean for fit
The 0.55 to 0.8 A setting range and 0.21 kW AC-3 rating define the motor it can start and protect — small three-phase motors up to that power at 400 V. The 50 kA short-circuit breaking capacity at 400 V means this starter can safely interrupt faults up to that level without upstream devices needing to clear the fault, which simplifies panel coordination. Communication is via AS-interface, not PROFIBUS DP, so verify your fieldbus architecture before specifying — this unit talks on the AS-i yellow cable, not a DP drop.
Integration notes
The enclosure measures 270 mm high, 120 mm wide, and 190 mm deep — panel-mount footprint is substantial; verify gland plate clearance for the 9-pole motor outgoing feeder and 9-pole power connection. Main circuit connections use tab terminals, so mating connectors need to match that form factor. Operating temperature range is -25 to +55 °C, which covers most indoor industrial environments but may need derating near ovens or in direct sun. The unit includes two integrated inputs for local sensors or pushbuttons, reducing external wiring.