Siemens 3RW4026-1BB04 SIRIUS Soft Starter For AC Motors

Siemens 3RW4026-1BB04 SIRIUS soft starter provides controlled soft-start and soft-stop for three-phase AC motors up to 11 kW at 400 V, with a nominal line current of 25 A (S0). It accepts a 200–480 VAC supply and uses a 24 V AC/DC control input, with screw-terminal connections for straightforward wiring. Rated for ambient temperatures up to 40°C, this compact device is designed for industrial environments where gentle ramping of motor voltage reduces inrush and mechanical stress. By applying voltage gradually through phase-angle control and ramping from an adjustable start voltage to the line voltage, it minimizes electrical disturbances and helps extend motor life, making it suitable for pumps, fans, conveyors, and other equipment that benefit from smooth acceleration. The 3RW4026-1BB04 is part of Siemens' SIRIUS soft-starter family and is specified for S0 operation, providing reliable performance from a single device without external control relays. Its 24 V control capability and compatibility with 200–480 V networks give users a precise match for medium-power, three-phase drives in control panels or enclosures, where a controlled start is essential and wiring is accomplished via screw terminals.