What this motor starter delivers
The Siemens 3RK1304-5LS70-2AA3 is a SIMATIC motor starter in a direct-start configuration, rated 12 A at 400 V AC for motor loads. Its adjustable trip class — selectable between CLASS 5, 10, 20, and 30 — lets you match the thermal overload curve to the motor's starting profile: fast tripping for short acceleration times, slower for high-inertia loads like fans or centrifuges. The unit carries a 100 kA SCCR at 400 V, meaning it can safely interrupt fault currents up to that level without upstream coordination failure — a key number for panel builders sizing branch protection. It runs on a 24 V DC control supply (20.4 to 28.8 V range) and supports both PROFINET and PROFIBUS DP protocols, so it drops into a Siemens automation network without a separate gateway.
Where it fits in the panel
Housed in an IP65 enclosure (230 x 110 x 160 mm), this starter is designed for distributed mounting — on a machine frame or in a field cabinet — not just a central control panel. The IP65 rating means the electronics and wiring are protected against dust ingress and low-pressure water jets, so it can sit near washdown zones or in dusty production areas. Mounting is by screw fixing, and the unit can be installed vertically or horizontally. The main energy infeed uses a socket per ISO 23570, which simplifies pre-wired harness integration. It provides 4 digital inputs via M12 sockets and 2 bytes of input/output data to the controller — enough for feedback and basic interlocks without a separate I/O block.