What this SIRIUS motor starter is and where it fits
The Siemens 3RK1325-6LS71-2AA0 is a SIRIUS direct motor starter — a self-contained unit combining a contactor, overload relay, and AS-Interface communication in an IP65 enclosure. It's sized for 5.5 kW at 400 V (7.5 hp at 460/480 V) and accepts 24 VDC control supply (20.4 to 28.8 V). The IP65 rating means the housing and the M12 addressing plug withstand washdown environments, so this starter lives right on the machine frame, not back in a clean panel.
Key ratings and what they mean for fit
Trip class is selectable among CLASS 5, 10, 15, and 20 — that's the maximum time in seconds the overload relay allows before tripping under a locked-rotor condition. Class 10 is the default for standard motor starting; Class 20 gives extra headroom for high-inertia loads like fans or centrifuges. The starter handles direct-on-line starts only (no reversing), so it's a fit for pumps, conveyors, and compressors that run one direction. Four digital inputs (M12, 24 VDC) are onboard for local start/stop and feedback — no separate I/O module needed. The main power circuit connects via a HAN Q4/2 plug (ISO 23570), which is a common industrial connector for motor feeds up to this power class. Pollution degree 3 means it's rated for conductive environments typical of factory floors. Mounting is flexible: vertical, horizontal, or flat, with screw fixing. The 294 mm width and 215 mm height are the panel footprint; depth is 159 mm including the connector. Operating temperature range is -25 to +55 °C, with storage down to -40 °C — fine for unheated warehouses.