Product Overview
The Siemens 3RW4455-6BC44 is a rugged SIRIUS soft starter designed for high-feature industrial motor control applications. This module mitigates inrush current and mechanical stress during motor start-up, ensuring smooth acceleration and extended equipment life. With integrated bridging contactors, thyristors, and comprehensive motor protection (overload, thermal resistor evaluation, and intrinsic device protection), the 3RW4455-6BC44 addresses common failure modes such as overheating, voltage sags, and mechanical wear. Its inside-delta circuit capability allows up to 710 kW at 400 V, making it suitable for demanding three-phase squirrel-cage motors.
Technical Specifications
Key performance parameters of the Siemens 3RW4455-6BC44 are listed below. All values are sourced from the product datasheet.
| Parameter |
Value |
| Rated operational current (40°C standard) |
693 A |
| Inside-delta rated current (40°C) |
1,200 A |
| Rated power at 400 V (inside-delta) |
710 kW |
| Control supply voltage |
230 V AC (50/60 Hz) |
| Adjustable motor overload protection range |
138 A (min.) |
| Active power loss at 40°C (typical) |
220 W |
| Ambient temperature during operation |
up to 60°C |
| Protection class |
IP00 |
| Dimensions (W x H x D) |
510 x 640 x 290 mm |
Real-World Applications
The Siemens 3RW4455-6BC44 excels in heavy industrial environments where motor starting causes voltage dips or mechanical shock. Typical applications include conveyors, compressors, pumps, and fans. Its adjustable current limitation and inside-delta wiring reduce peak current by up to 58% compared to direct-on-line starting, preventing nuisance tripping and reducing thermal stress on windings. For example, in a cement plant’s main crusher motor, the soft starter ensures gradual torque buildup, eliminating belt slippage and reducing maintenance.
Installation & Setup Guidance
Mount the Siemens 3RW4455-6BC44 using screw fixing on a vertical surface. Maintain minimum clearances: 100 mm above, 75 mm below, and 5 mm sideways for proper airflow. The main circuit uses busbar connections (stranded 70–240 mm² or finely stranded 50–240 mm²), while auxiliary circuits use screw terminals (2x 0.5–2.5 mm² solid). Ensure control supply voltage is 230 V AC at 50/60 Hz (±10% frequency tolerance). For inside-delta configuration, follow the motor manufacturer’s wiring diagram. Cable length must not exceed 500 m.
Maintenance & Reliability
Routine inspection every 6 months includes checking thyristor heat sinks for dust accumulation and verifying terminal torque. The integrated motor overload protection and thermal resistor evaluation reduce the risk of winding damage. Operating within the 40°C derating temperature ensures long service life. The IP00 enclosure requires installation in a clean, dry cabinet. With proper maintenance, the 3RW4455-6BC44 provides reliable start/stop cycles for years.
Selection Guide & Purchasing Advice
Before purchasing, verify the motor’s full-load current and supply voltage (200–460 V AC). The Siemens 3RW4455-6BC44 is ideal for motors up to 710 kW in inside-delta or 400 kW in standard configuration. Ensure your control system provides a 230 V AC control signal. For additional support, contact ubest101 – authorized distributor of Siemens industrial automation parts. We stock this exact module with fast shipping.