The Siemens 3RK1322-0HS02-1AA1 is an AS-Interface compact reversing starter — a self-contained motor control unit that handles forward/reverse switching, overload protection, and bus communication in one IP65 enclosure. It's designed for distributed motor control right at the machine, not back in a central panel. Rated for 0.21 kW at AC-3 duty on a 400 V line, it switches small three-phase motors — think conveyor drives, agitators, or valve actuators — up to that load. The setting range of 0.55 to 0.8 A means you dial the overload relay to match the motor's full-load current within that window. IP65 rating means the housing and all connections are sealed against hose-directed water and dust ingress. This unit mounts directly on the machine frame or a mounting plate near the motor — no separate enclosure needed.
That's a high fault-current rating for a compact unit — it lets you place it on a supply with substantial transformer capacity without needing upstream current-limiting fuses. Motor protection uses a bimetal overload relay — a thermal element that tracks motor heating. It's the traditional, field-proven approach; no electronics to fail in high-vibration or hot environments. The 0.55 to 0.8 A adjustment range covers small motors in the 0.21 kW class. The built-in motor brake output (24 V DC / 3 A) supplies power to release a spring-applied brake on the motor shaft. That's critical for vertical loads or any axis that must hold position when power is removed — the brake engages on power loss, preventing drift. Communication is over AS-Interface (AS-i), not PROFIBUS DP. Two integrated inputs let you wire limit switches or pushbuttons directly into the starter, reducing field wiring back to a central I/O rack.
Physical integration
Dimensions are 120 mm wide, 270 mm high, 190 mm deep. It's not a DIN-rail mount — the IP65 enclosure bolts directly to a machine frame or sub-plate via its mounting feet. The 9-pole tab terminals for the main circuit accept standard quick-connect receptacles; no screw terminals on the power side. The IP65 seal holds up to washdown cycles, so it's suitable for food, beverage, or pharmaceutical lines where hosing down the machine is routine.