The Siemens 3RK1325-6KS41-2AA5 is a SIRIUS direct motor starter rated for 0.75 kW at 400 V (0.7 hp at 460/480 V, 1 hp at 575/600 V), with trip classes 5, 10, 15, and 20 selectable on the device. It is a fully enclosed IP65 unit designed for on-site operation via AS-Interface protocol, carrying four digital inputs and a HAN Q4/2 main circuit connector per ISO 23570.
The 0.75 kW at 400 V rating covers a standard 1 hp 4-pole induction motor on a 400 V three-phase line; the 1 hp at 575/600 V rating extends coverage to North American 600 V class supplies. Trip class selection (5, 10, 15, 20) lets you match the overload release to the motor's thermal time constant — Class 10 for standard pumps and fans, Class 20 for high-inertia loads like centrifuges or crushers that take longer to start. The 24 V DC supply (20.4 to 28.8 V range) is standard for industrial control panels; the 31.6 V maximum permissible voltage gives headroom for a poorly regulated supply. Mounting is screw-fix to a backplate, not DIN-rail snap-on. The 294 mm width and 215 mm height mean it occupies a full panel footprint — plan gland-plate entry and cable routing accordingly.
AS-Interface integration
This starter communicates via AS-Interface protocol (not PROFIBUS or PROFINET). Addressing is done through the M12 plug on the device. The four digital inputs are available for local sensors or pushbuttons, reducing the need for a separate I/O block. ON-delay is 85 ms, OFF-delay 65 ms — fast enough for most conveyor interlocking but not for safety-rated stop circuits.