What this soft starter does and who needs it
The Siemens 3RW5243-2AC05 is a SIRIUS hybrid switching device — a soft starter sized for three-phase induction motors drawing a minimum of 90 A, with a rated voltage range of 200 to 600 V. Its default Trip Class 10A (with selectable 10E and 20E per IEC 60947-4-2) means it protects standard squirrel-cage motors during start-up by limiting inrush current and torque, while still tripping fast enough to avoid winding overheating on a stall. The 393 mm height and 210 mm width with screw fixing suit it for large panel builds where vertical mounting space is available.
Fieldbus and control integration
This soft starter ships with native support for Modbus RTU, Modbus TCP, PROFIBUS, EtherNet/IP, and PROFINET including PROFIenergy — so it drops into most modern control architectures without an external gateway. The analog output is configurable as 4-20 mA or 0-10 V (the latter requires the High Feature HMI accessory), giving the PLC a direct motor current or torque signal. Remote reset is handled by cycling the 24 V control supply, and the auto-reset function lets the starter re-start after a fault without a manual button push — useful for remote or unattended pump stations.
Mount the unit with screw fixing on a vertical surface; it can be rotated ±90° or tilted ±22.5° front-to-back. Shock resistance is 15 g / 11 ms, dropping to 12 g / 11 ms if contact lifting is a concern. The 203 mm depth and 100 mm upward clearance requirement mean it fits in standard 800 mm deep enclosures, but leave the full 100 mm above for cable bending and airflow.