The Siemens 3RW4047-1TB04 is a SIRIUS soft starter in size S3, rated 106 A at 40 °C ambient — that is the current it can handle continuously when the panel stays at 40 °C. The 24 V control voltage is the same at 50 Hz and 60 Hz, which simplifies wiring across mixed-frequency plants. Screw-type terminals on the main circuit accept 2x (10 … 70 mm²) stranded or 2x (10 … 50 mm²) finely stranded, and the auxiliary contacts take 2x (20 … 14 AWG). Mounting is screw and snap-on to DIN rail, with clearances: 60 mm upward, 40 mm downward, 30 mm at the sides.
Deployment context — panel integration and motor protection
This soft starter mounts on DIN rail in a standard control panel. It includes motor overload protection and intrinsic device protection, so it can serve as the sole motor branch component for overload and short-circuit coordination up to its rated insulation voltage of 600 V. The adjustable current limitation lets you tune the starting torque to the load — pumps, conveyors, fans — without a separate current-limiting reactor. Minimum load is 20 % of the rated current, so it will not regulate properly below that threshold; size the motor so the running current stays above 21 A at 40 °C ambient. The thyristor output stage provides a ramped voltage start, reducing mechanical shock and inrush compared to a direct-on-line contactor.