What the 3RW5217-1AC05 delivers for a motor-starting application
The Siemens 3RW5217-1AC05 is a SIRIUS soft starter rated for a minimum motor current of 15.5 A across a 200–600 V supply range, with a 24 V DC control voltage. Its default trip class is CLASS 10A (per IEC 60947-4-2), meaning it protects standard induction motors during start-up by limiting the inrush duration to roughly 10 seconds at 6× rated current — a solid fit for pump, fan, and conveyor applications where a hard start would cause mechanical stress or nuisance tripping. The unit supports multiple fieldbus protocols out of the box: PROFIBUS, Modbus RTU, Modbus TCP, EtherNet/IP, and PROFINET (with PROFIenergy for energy management). This makes it a natural choice for a plant that has standardized on Siemens automation but also needs to talk to third-party PLCs over Ethernet/IP or Modbus TCP without an extra gateway. It includes an analog output (4–20 mA default, or 0–10 V parameterizable via the High Feature HMI), which lets the panel builder feed a real-time motor current signal to a PLC analog input card or a local panel meter — useful for monitoring load on a critical pump without adding a separate current transducer.
Mounting and wiring — what fits in the panel
Dimensions are 170 mm wide by 275 mm high by 152 mm deep, with screw fixing to a vertical mounting surface. The unit can be rotated ±90° and tilted ±22.5° front-to-back, giving the panel builder some layout flexibility inside a crowded enclosure. Clearance requirements: 100 mm above, 75 mm below, 10 mm in front, 5 mm at the sides, and 0 mm behind. That zero back clearance means it can sit flush against the back panel — handy when you're trying to squeeze a soft starter into an existing MCC bucket. Power terminals accept solid or stranded wire: 2x (1.0–2.5 mm²) and 2x (2.5–10 mm²). That covers most motor feeder sizes up to about 10 mm², which is typical for a 15.5 A minimum-rated device. Strip length and ferrule sizing follow standard IEC practice.
Operating conditions and reset behavior
Shock resistance is 15 g for 11 ms (12 g with potential contact lifting). This is a rugged industrial device, but if the panel sits in a hot machine room near an oven, the derating curve matters. The soft starter supports both automatic reset (auto-RESET) and remote reset by cycling the 24 V DC control supply. That remote reset feature is a practical time-saver for a maintenance technician who can cycle power from a central control room instead of walking to the panel and pressing a button. Additional soft-start features include Soft Torque and Pump Ramp Down — both designed to reduce mechanical shock on the load. Pump Ramp Down is particularly useful on water/wastewater lines where a sudden stop can cause pressure surges and pipe hammer.
The CE marking covers the Low Voltage Directive and EMC Directive; UL and CSA cover the US and Canadian markets.