Siemens 3RW4038-1BB14 Soft Starter Sirius Series

Siemens 3RW4038-1BB14 SIRIUS Soft Starter is a Size S2 device that provides reduced-voltage starting for three-phase motors, helping minimize electrical and mechanical stress during startup. It is rated for 72 A and 37 kW at 400 V with a 40 °C rating, and accepts a supply range of 200-480 V AC, with a control voltage of 110-230 V AC/DC via screw terminals. The unit features an integrated bypass contact system and thyristor-based soft-start control, along with intrinsic device protection, motor overload protection, external reset capability, and adjustable current limiting; there is no motor brake output. The compact design is intended for standard industrial drives and is compatible with typical Siemens SIRIUS configurations, making it suitable for pumps, fans, conveyors, machine tools, and other machinery where controlled startup and motor protection are essential.