The Siemens 3RW4056-6BB44 is a SIRIUS soft starter, Size S6, built for three-phase induction motor starting. It delivers 162 A at 40 °C (145 A at 50 °C, 125 A at 60 °C) and carries a 600 V insulation rating. The thyristor-based design ramps voltage to limit inrush current, with adjustable current limitation and motor overload protection built in — no external overload relay needed for most installations. Rated operating frequency is 50 to 60 Hz at 230 V. The 20% minimum load setting means it handles lightly loaded motors without nuisance tripping.
Screw-fixed mounting with a 250 mm depth, 120 mm width, 198 mm height. Clearance requirements: 100 mm above, 75 mm below, 5 mm at the sides. With an additional fan, you can rotate the unit ±90° on a vertical surface or tilt it ±22.5°; without the fan, rotation and tilt are limited to ±10° each. Busbar connection for the main current circuit; main terminals accept 4 to 250 kcmil, auxiliary terminals accept 2x (20 to 14 AWG) solid or 2x (0.5 to 2.5 mm²) fine-stranded. Wire length from the starter to the motor should not exceed 300 m — keep that in mind if the motor is remote. The internal-delta circuit is not supported, so this unit goes in-line with the motor leads, not in the delta loop.