What this soft starter does for the route
The Siemens 3RW5545-6HA16 is a SIRIUS 3RW55 soft starter built for three-phase induction motors on 200 to 690 V supplies. It carries ATEX and IECEx certification, so it's approved for explosive atmospheres — that's the main reason someone hunting this order code needs it. The control voltage range is 110...250 V AC at either 50 or 60 Hz, meaning it'll work on common plant voltages without a step-down transformer. Trip class is selectable: default is CLASS 10A / 10E, but you can set it to 20E or 30E per IEC 60947-4-2. That gives you flexibility for different load types — fast starts for pumps, slower ramps for high-inertia loads like centrifuges or conveyors. The service factor is 1.15, so it can handle a 15% continuous overload without tripping.
Dimensions are 210 mm wide, 393 mm high, 203 mm deep. Clearance requirements: 100 mm upward, 75 mm downward, 10 mm forward, 0 mm backward, and 5 mm at the sides. That backward-zero clearance means it can sit flush against a panel backplate — handy for tight enclosures. Terminations are screw-type, so standard ring or fork lugs work fine. Communication options are broad: PROFIBUS, Modbus RTU, Modbus TCP, and EtherNet/IP are all built in — no separate option card needed for most fieldbuses. PROFIenergy is supported when used with PROFINET High-Feature modules, which helps with energy management during idle periods.
Protection and control features
This soft starter includes DC braking for quick stops, voltage ramp for smooth acceleration, pump ramp down to avoid water hammer, torque control, and a breakaway pulse to start sticky loads. Accuracy class is 5 per IEC 61557-12, which is good enough for motor protection and energy monitoring. It logs events, errors, and has a trace function for diagnosing start-up issues. Analog output is configurable as 4...20 mA (default) or 0...10 V, so it can feed a panel meter or PLC analog input with motor current or other parameters. Firmware is field-updatable, and there are four parameterizable digital inputs/outputs.