Siemens SIRIUS 3RW3028-1BB04 Soft Starter, 3-Phase, 18.5kW, 38A, 200-480V AC, 24V AC/DC

The Siemens SIRIUS 3RW3028-1BB04 is a high-performance, compact 3-phase soft starter engineered to provide smooth starting and stopping for industrial electric motors. By controlling the voltage supplied to the motor, this device effectively minimizes mechanical stress on drive components and reduces high current peaks during startup. It is designed for seamless integration into electrical control systems, offering a reliable solution for applications requiring controlled motor acceleration and deceleration.

Advantages

This soft starter offers significant benefits by extending the service life of motors and connected mechanical equipment such as belts, gears, and couplings. Its compact S0 size allows for space-efficient installation in control cabinets, while the integrated design simplifies wiring and commissioning. The device ensures stable operation by preventing voltage dips in the power supply network, contributing to a more efficient and durable industrial electrical infrastructure.

Suitable for

• Conveyor systems and transport belts
• Pumps and hydraulic systems
• Fans and ventilation units
• Compressors
• Small machine tools

This soft starter is not suitable for applications requiring high starting torque or frequent switching cycles, as it is designed for standard soft-start operations. It should not be used in environments where heavy-duty starting conditions or precise speed control are required, as it does not provide variable frequency drive functionality.

Key specifications

• Power rating: 18.5kW at 400V
• Rated operational current: 38A
• Supply voltage range: 200-480V AC
• Control supply voltage: 24V AC/DC
• Size: S0
• Phase: 3-phase

How to use

Installation should be performed by qualified personnel in accordance with local electrical regulations. The device is mounted on a standard DIN rail or via screw mounting within a control cabinet. Connect the main power supply to the input terminals and the motor leads to the output terminals. Ensure the control voltage of 24V AC/DC is correctly wired to the control inputs. Once installed, the soft starter operates automatically based on the internal ramp-up settings to provide a smooth motor start.

What to consider before purchase

• Verify that the motor power rating matches the 18.5kW capacity.
• Ensure the control voltage of 24V AC/DC is compatible with your existing control system.
• Check that the supply voltage of the installation site falls within the 200-480V AC range.
• Confirm that the physical dimensions of the S0 size unit fit within your designated cabinet space.

Usage recommendations: Regularly inspect the terminal connections for tightness and ensure adequate ventilation around the unit to prevent overheating during continuous operation.