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SIRIUS 3RW40 — Siemens Soft Starters
The SIRIUS 3RW40 series from Siemens is a range of soft starters designed for standard starting and stopping of three-phase asynchronous motors. Featuring thyristor control technology and an integrated bypass contactor, the 3RW40 series delivers a compact design with minimal heat dissipation in the control cabinet. The rated current range from 12 to 432 A at 400 V covers motors from 5.5 to 250 kW.
Key advantages of the SIRIUS 3RW40: simple parameterization via potentiometer (no programming required), intelligent overheating and motor overload protection, adjustable starting current limitation, and two-phase control with polarity balancing.
SIRIUS 3RW40 Product Lineup
| Part Number | Rated Current, A | Voltage, V |
|---|---|---|
| 3RW4024-1BB14 | 12 | 400 |
| 3RW4026-1BB14 | 25 | 400 |
| 3RW4028-1BB14 | 38 | 400 |
| 3RW4046-1BB14 | 80 | 400 |
| 3RW4055-6BB44 | 134 | 400 |
| 3RW4074-6BB44 | 280 | 400 |
| 3RW4076-6BB44 | 432 | 400 |
The complete catalogue includes 15 models with intermediate ratings of 32, 45, 63, 72, 106, 162, 230, and 356 A.
How to Choose a SIRIUS 3RW40
Selecting the right 3RW40 soft starter is based on the motor's rated current at operating temperature. For standard conditions (up to 40 °C), use catalogue values. At elevated ambient temperatures (50-60 °C), the permissible current derating must be considered. It is recommended to select a model with a 10-15 % margin above the motor's rated current.
The 3RW40 series is designed for direct starting with a smooth voltage ramp-up. For heavy-duty starting, reversing applications, or advanced diagnostics requirements, consider the Siemens SIRIUS 3RW44 — a series with extended functionality.
Other Soft Starter Series
In addition to Siemens, we offer soft starters from other manufacturers: Schneider Electric ATS48 for demanding starting applications, Danfoss MCD500 with a comprehensive protection set, and Siemens SIRIUS 3RW30 for compact solutions.
Warranty and Support
All Siemens SIRIUS 3RW40 soft starters come with the manufacturer's official warranty. Our engineers can assist with selection, configuration, and commissioning of the soft starter for your equipment.
