3RW4038-1BB14, Soft Starter, 37 kW, 72 A, 200 to 480V AC

Siemens 3RW40 Soft Starter Series – Overview

Siemens 3RW40 soft starters are advanced compact motor starting solutions designed for smooth starting and stopping of three-phase asynchronous motors in industrial applications. The 3RW40 series focuses on reducing mechanical stress, limiting inrush current, and providing enhanced motor protection compared to basic soft starters. With integrated bypass functionality and flexible configuration options, Siemens 3RW40 soft starters are well suited for pumps, fans, compressors, conveyors, and general industrial machinery requiring reliable and efficient motor starting.

Product Description: 3RW4038-1BB14

The Siemens 3RW4038-1BB14 is a SIRIUS series soft starter rated for 72 A continuous operation and sized for motors up to 37 kW at 400 V (standard circuit). It accepts a wide three-phase supply voltage range of 200–480 V AC and uses a 110–230 V AC/DC control supply. The device implements two‑phase controlled starting with an adjustable start voltage (40–100% of line voltage) and configurable start/stop times (0–20 s), providing a voltage-ramp soft start that reduces mechanical stress and limits inrush current for pumps, fans, conveyors and other industrial machines. Built-in bypass contacts reduce on‑losses after start-up, while integrated solid‑state motor overload protection and adjustable current limiting provide basic motor protection without external relays. The compact DIN-rail mountable unit (IP00) is suitable for control panels where space is limited and where a straightforward, reliable motor soft starter is required.

Key Soft Starter Attributes