Key Features and Technical Specifications
The 3RW4055-6BB44 is packed with features that improve motor control and protection. Below are the core specifications extracted directly from the datasheet:
- Rated operating current: 134 A at 40 °C (117 A at 50 °C, 100 A at 60 °C)
- Operating voltage: 200 ... 460 V AC (standard circuit)
- Operating frequency: 50 ... 60 Hz
- Control supply voltage: 230 V AC (at 50 Hz and 60 Hz)
- Mechanical power output: 75 kW at 400 V (standard circuit, 40 °C); 37 kW at 230 V
- Size: S6
- Protection class: IP00
- Ambient temperature: -25 ... +60 °C (operation), -40 ... +80 °C (storage)
- Integrated bypass contact system: Yes
- Thyristors: Yes
- Motor overload protection: Yes
- Adjustable current limitation: Yes
One distinctive feature is the adjustable current limitation, which lets you set the maximum motor current during starting. This protects both the motor and the driven machinery from excessive torque, extending equipment life.
Applications and Use Cases
The 3RW4055-6BB44 is ideal for pumps, fans, compressors, and conveyors where controlled starting is critical. In pumping systems, it reduces water hammer by gradually ramping up pressure. For conveyor belts, it minimizes mechanical shock to gears and couplings. Additionally, in HVAC applications, the soft starter ensures smooth fan startup, reducing belt wear and electrical spikes.
Because of its robust design and wide voltage range, this soft starter suits both new installations and retrofit projects. Its compact S6 size allows easy integration into existing motor control centers.
Installation and Mounting
Proper installation is essential for optimal performance. The 3RW4055-6BB44 supports screw fixing and offers flexible mounting positions. With an additional fan, it can be mounted with a vertical surface and rotated ±90°; without a fan, ±10° rotation is allowed. Ensure adequate spacing: 100 mm upward, 5 mm sideways, and 75 mm downward for side-by-side mounting.
Connect the main circuit using busbar connections, and use screw-type terminals for auxiliary and control circuits. The device accepts conductor cross-sections from 16 to 70 mm² for main contacts, and 2x (0.5 ... 2.5 mm²) for auxiliary contacts. Always follow the manufacturer's manual for detailed wiring instructions.
Maintenance and Reliability
The integrated bypass contact system reduces heat generation, which enhances reliability and extends service life. Regular inspection per the manufacturer's guidelines is recommended to ensure all connections remain tight and the unit operates within its specified ambient temperature range. The IP00 protection class means the unit should be installed in a suitable enclosure to prevent dust and moisture ingress.
With a maximum cable length of 300 m, you can place the soft starter away from the motor if needed. The device also features intrinsic device protection, safeguarding against overcurrent and overtemperature conditions.
Compatibility and Integration
As part of the Siemens SIRIUS family, the 3RW4055-6BB44 integrates seamlessly with other Siemens control components. It provides two NO contacts and one CO contact for auxiliary signaling, allowing easy connection to PLCs or motor control circuits. The control supply voltage is 230 V AC, compatible with standard industrial control systems.
Troubleshooting and Common Issues
Common issues with soft starters include overheating, nuisance trips, and motor not starting. To avoid these, verify that the operating current does not exceed the rated value at the ambient temperature. For instance, at 50 °C, the rated current drops to 117 A; at 60 °C, it is 100 A. Ensure proper ventilation and spacing to maintain cooling.
If the motor overload protection trips, check the adjustable motor current setting (minimum 59 A) and adjust it to match the motor's full-load current. Also, confirm that the control supply voltage is within tolerance (±15% negative, +10% positive).
Product Support and Availability
The 3RW4055-6BB44 is available from AutoDCSTech, a trusted supplier of industrial automation parts. Please verify current lifecycle status and availability with AutoDCSTech before ordering. Our team can assist with technical questions and ensure you receive the correct component for your application.
Availability & Condition at AutoDCSTech
| Part Number | 3RW4055-6BB44 |
|---|---|
| Availability | In Stock |
| Condition | New |
| Warranty | One Year |
| Origin | Germany |
