Siemens SIRIUS Soft starter, S2, spring terminals, 24VAC/DC, 63A Part number 3RW4037-2BB04

Product Overview

The Siemens 3RW4037-2BB04 is a SIRIUS 3RW40 soft starter (size S2) designed for gentle, controlled starting of three-phase induction motors. It supports a rated operational current of 63 A and is suitable for motors up to 30 kW at 400 V. With an operating voltage range of 200…480 V AC and a 24 V AC/DC control supply, this soft starter provides reliable reduction of starting current, minimized mechanical stress, and improved system protection. An integrated bypass contact system increases efficiency and reduces heat dissipation once the motor reaches full speed.

Key Features

• Soft starter for three-phase induction motors (SIRIUS 3RW40 series)
• Rated operational current: 63 A
• Motor power rating: up to 30 kW at 400 V
• Supply voltage range: 200…480 V AC
• Control supply voltage: 24 V AC/DC
• Integrated bypass contact system for efficient operation
• Thyristor-based soft start and soft stop functionality
• Spring-type terminals for the control circuit; screw terminals for the main circuit
• Compact size S2 housing (55 mm width)

Technical Specifications

• Product Series: SIRIUS 3RW40
• Article Number: 3RW4037-2BB04
• Rated Operational Current (Ie): 63 A at 40 °C
• Rated Motor Output: 30 kW at 400 V AC
• Main Voltage (Ue): 200…480 V AC, 3-phase
• Control Supply Voltage (Us): 24 V AC/DC
• Width: 55 mm (Size S2)
• Height: approx. 160 mm
• Depth: approx. 170 mm
• Operating Ambient Temperature: –25 °C to +60 °C
• Main Terminal Conductor Sizes: Solid 1.5–16 mm², stranded up to 35 mm²
• Number of Poles: 3-pole motor circuit

Compliance & Certifications

• Designed to Siemens SIRIUS soft starter standards
• Conforms to IEC/EN 60947-4-2 for motor starting devices
• Meets industrial safety, performance, and reliability requirements

Applications

Suitable for pumps, fans, compressors, conveyors, and general machinery requiring smooth motor acceleration. The soft starter reduces mechanical wear, limits inrush current, and provides a more efficient alternative to traditional star-delta starters in industrial automation and process environments.