SIRIUS reversing starter — panel-mount, AS-Interface controlled
The Siemens 3RK1325-6LS41-1AA5 is a SIRIUS reversing motor starter in an IP65 enclosure, rated 5.5 kW at 400 V and configurable for trip classes 5, 10, 15, or 20. It communicates via AS-Interface protocol, addressed through an M12 plug, and accepts a 24 V DC supply (20.4–28.8 V range). The unit is screw-fixed into the panel and can be mounted vertically, horizontally, or flat — the manufacturer recommends horizontal orientation for best thermal performance.
What the ratings mean for your panel
IP65 means the enclosure is dust-tight and protected against low-pressure water jets — suitable for washdown zones or outdoor cabinets without an additional enclosure. The 5.5 kW rating at 400 V AC-3 duty tells you the starter can switch a 3-phase induction motor of that output under normal starting conditions; the same unit also carries ratings of 3 hp at 230 V, 7.5 hp at 480 V, and 10 hp at 600 V for North American line voltages. Trip class selection (5, 10, 15, 20) sets the thermal overload curve — class 10 matches standard motor protection for most pumps and fans; class 20 allows longer inrush for high-inertia loads like centrifuges. The reversing function means two contactors are interlocked inside the same housing, so a single command flips motor rotation without external interlocking wiring. The AS-Interface connection carries both power and data on a single two-wire cable, reducing field wiring compared to a parallel I/O run. Four digital inputs are available on the module for local limit switches or pushbuttons.
Mechanical fit and environmental limits
Dimensions are 294 mm wide, 215 mm tall, and 159 mm deep — this is a wide-format reversing starter, so verify DIN-rail clearance or backplate space before committing. Screw fixing is the only fastening method; no snap-on DIN rail clip is used. Operating temperature range is -25 to +55 °C; storage and transport tolerate -40 to +70 °C. Shock resistance is rated at 12g for 11 ms, and vibration resistance at 7 mm / 2g — adequate for most industrial machinery but check against your specific machine's environment.
Switching times and pollution degree
ON-delay is 85 ms, OFF-delay is 65 ms — these are the internal response times from command to main contact closure. Pollution degree 3 means the unit is rated for conductive pollution in industrial atmospheres. The maximum permissible supply voltage is 31.6 V DC, with a minimum of 26.5 V DC for reliable operation.