Softstart SIRIUS 3RW44

Siemens SIRIUS 3RW44 — High-Performance Soft Starters for Industrial Applications

The SIRIUS 3RW44 series by Siemens is a range of high-performance soft starters rated from 551 to 1214 A at 400 V. These soft starters are designed for smooth starting and stopping of heavy-duty induction motors in demanding industrial environments: pump stations, compressor systems, ventilation units, conveyor lines and other machinery with high starting torque requirements.

Unlike the basic SIRIUS 3RW40 series, the 3RW44 lineup features a built-in bypass contactor that automatically shunts the thyristors after the motor reaches full speed, significantly reducing heat losses. Additionally, optional PROFIBUS DP and PROFINET communication modules enable full integration into industrial automation networks.

SIRIUS 3RW44 Product Lineup

The full range of 8 SIRIUS 3RW44 models is available in the catalogue with detailed technical specifications for each part number.

Key Advantages of the 3RW44 Series

• Built-in bypass contactor — automatic thyristor shunting after ramp-up reduces heat generation and extends device lifespan.
• Communication interfaces — optional PROFIBUS DP and PROFINET modules enable remote control, diagnostics and integration with SCADA/PLC systems.
• Advanced protection — overload monitoring, phase loss detection, locked rotor protection, phase asymmetry and overtemperature control.
• Standards compliance — certified to IEC/EN 60947-4-2.
• Operating conditions — temperature up to +60 °C, installation altitude up to 5,000 m above sea level.

How to Choose a 3RW44 Soft Starter

The SIRIUS 3RW44 series is optimal for applications requiring power above 250 kW and industrial communication capabilities. Key selection criteria:

• Motor rated current — select a model with a 10–15% margin above the motor's nominal current.
• Supply voltage — all 3RW44 models are rated for 400 V, 3-phase supply.
• Communication needs — if the motor is controlled from a PLC via PROFIBUS or PROFINET, the 3RW44 series provides full integration.

For lower-power motors (up to 250 kW), consider the basic SIRIUS 3RW40 series or the compact SIRIUS 3RW30.

Other Soft Starter Series

In addition to Siemens, our catalogue features soft starters from other leading manufacturers:

• Siemens SIRIUS 3RW40 — basic series for standard applications (up to 45 A).
• Siemens SIRIUS 3RW30 — compact soft starters for smaller motors.
• Schneider Electric Altistart ATS48 — series for heavy-duty starting conditions.
• Danfoss MCD 500 — versatile soft starters with advanced functionality.

Warranty and Service

All Siemens SIRIUS 3RW44 soft starters are supplied with the manufacturer's official warranty. We provide technical consultation for selection, delivery across Ukraine and after-sales support.