SIMATIC reversing starter with integrated communication
The Siemens SIMATIC 3RK1304-5KS70-3AA3 is a fully integrated reversing motor starter in the SIMATIC motor starters family, designed for direct-on-line reversing control of three-phase motors up to 2 A at 400 V AC. The 24 V DC control supply (20.4 to 28.8 V range) keeps it compatible with standard PLC outputs. This unit is a reversing starter, so it handles forward/reverse motor direction without external contactor interlocking. It supports both PROFINET and PROFIBUS DP protocols, making it straightforward to drop into a SIMATIC S7 or third-party controller network. The IP65 enclosure means the entire assembly is washdown-rated — suitable for food-and-bev lines or wet process areas where dust and hose-down are routine.
Adjustable trip class and digital I/O
The trip class is field-selectable among CLASS 5, 10, 20, and 30. This lets you match the overload protection to the motor's thermal time constant — CLASS 10 for standard induction motors, CLASS 20 for high-inertia loads like fans or centrifuges, CLASS 30 for very long start-up times. It is not a direct-start device, meaning the starter expects a separate control signal to initiate each direction. Four digital inputs are provided via M12 sockets, which handle start/stop and direction commands from sensors or pushbuttons. The I/O mapping occupies 2 bytes each for inputs and outputs on the fieldbus, which is a compact footprint for the controller's process image. No brake control output is included; if you need a holding brake, add an external relay.
Mounts via screw fixing in either vertical or horizontal orientation. Dimensions are 230 mm height, 110 mm width, 160 mm depth — it occupies a compact footprint for a reversing starter with integrated bus interface. The enclosure is rated IP65, so it can be mounted directly on the machine frame without a separate panel, as long as the ambient stays within -25 to +55 °C operating and -40 to +70 °C storage/transport.