Siemens 3RW40371BB04 Soft Starter Motor Control

Product Description

The SIEMENS 3RW40371BB04 is a solid-state soft starter designed to control the acceleration and deceleration of three-phase AC motors. By ramping voltage up gradually at startup, it reduces inrush current and mechanical stress on the motor and driven equipment. This type of device is installed in motor control centers, control panels, and standalone enclosures across industrial, commercial HVAC, and pump applications. The unit measures 6.654 x 2.697 x 7.677 inches and weighs approximately 2.866 pounds, making it a compact option for panel integration. Licensed electricians and industrial controls technicians are the primary installers.

The 3RW40371BB04 is suited for applications where full-across-the-line starting would cause excessive mechanical shock or electrical demand spikes. Common use cases include conveyor drives, compressor motors, pump systems, and fan arrays in commercial and light industrial settings. It is intended for three-phase motor load control and fits into standard DIN-rail or panel-mount configurations typical of motor control enclosures.

Key Features

• Soft start and soft stop function reduces motor inrush current and mechanical wear
• Solid-state design with no moving contact parts for long service life
• Compact footprint at 6.654 x 2.697 x 7.677 inches supports space-constrained panel builds
• Lightweight at 2.866 pounds for easier panel integration and mounting
• Suitable for three-phase AC motor loads in commercial and industrial control systems

Compatibility

Designed as an OEM-style soft starter for three-phase AC motor control applications in commercial and industrial motor control enclosures and panels.

Installation Notes

Installation should be performed by a licensed electrician in accordance with the National Electrical Code (NEC) and all applicable local codes. Disconnect and lock out all power sources before handling or wiring the soft starter. Verify that the panel supply voltage, motor full-load amperage, and control wiring match the unit specifications before energizing. Do not bypass the soft starter or connect it to single-phase loads.

Technical Specifications

• Length: 6.654 inches
• Width: 2.697 inches
• Height: 7.677 inches
• Weight: 2.866 pounds
• UPC: 04089278313

Standard Information

• Brand: SIEMENS
• Manufacturer Part Number: 3RW40371BB04