It uses thyristor switching to ramp motor voltage during start, limiting inrush current and mechanical stress on the driven load — conveyor belts, pumps, or compressors in a process line. The unit includes integrated motor overload protection and supports inside-delta circuit wiring, which reduces the rated current requirement on the soft starter for a given motor by roughly 40% compared to standard in-line connection.
The headline current rating of 617 A at 40 °C derates to 546 A at 50 °C and 485 A at 60 °C — the ambient temperature inside the panel governs which figure applies. If the enclosure runs at 50 °C, the soft starter is good for a 546 A motor FLA, not 617 A.
Mounts via screw fixing on a vertical surface, rotatable ±90° and tiltable ±22.5° front-to-back — gives flexibility in tight cabinets. Clearance required: 100 mm above, 75 mm below, 5 mm at the sides. Dimensions are 230 mm high × 210 mm wide × 298 mm deep. Main circuit connections accept busbar or cable: stranded 70–240 mm², finely stranded 50–240 mm², or AWG 2/0–500 kcmil. Auxiliary control wiring uses solid 0.5–2.5 mm² or AWG 20–14. Maximum wire length from soft starter to motor is 500 m — sufficient for most plant layouts, but check voltage drop on long runs.
The 3RW4446-6BC44 carries a lifecycle status of current production. The part belongs to the Siemens SIRIUS family, a widely specified platform, so cross-referencing into existing BOMs is straightforward.