Siemens 3RW4422-1BC34 AC Semiconductor Motor Starter

Siemens 3RW4422-1BC34 is a SIRIUS AC semiconductor motor starter (soft starter) that delivers smooth, controlled acceleration for 3-phase motors, reducing mechanical stress and electrical inrush during startup. It accepts 200-460 V AC mains (UE) with a dedicated 115 V AC control circuit (US); in standard 460 V operation it is rated at 26 A and 15 HP, while the inside-delta configuration supports up to 45 A and 30 HP. The unit employs screw-terminal connections for straightforward field wiring and, as part of the SIRIUS soft-start line, integrates motor protection and semiconductor protection features, enabling reliable soft-start performance with adjustable ramp characteristics and safe-handling of startup transients. Common applications include conveyors, fans, pumps, and compressors where a gentle ramp-up and controlled deceleration are beneficial, especially in systems sensitive to inrush or mechanical shock.