Siemens 3RW3027 Soft Starter, 32A, 15kW at 400V, 7.5kW at 230V, 400V AC

The Siemens 3RW3027 soft starter is a high-performance solution engineered for the controlled starting and stopping of three-phase asynchronous motors. By regulating the voltage supplied to the motor, this device ensures a smooth acceleration process, effectively eliminating the mechanical shocks and high inrush currents typically associated with direct-on-line starting. Its compact design and robust construction make it an essential component for industrial automation systems requiring reliable motor protection and extended equipment lifespan.

Advantages

The primary benefit of using this soft starter is the significant reduction in mechanical stress on drive components such as belts, gears, and couplings, which leads to lower maintenance costs and fewer unplanned downtimes. By minimizing current peaks during the startup phase, the device also helps to stabilize the electrical grid and prevents voltage drops that could affect other sensitive equipment in the facility. Its compact size allows for space-saving installation in control cabinets, while the intuitive design ensures straightforward integration into existing motor control architectures.

Suitable for

• Conveyor belt systems
• Pumps and hydraulic systems
• Fans and ventilation units
• Compressors
• Centrifuges

This soft starter may not be suitable for applications requiring high starting torque, as it reduces voltage to achieve a soft start. It is also not intended for frequent reversing operations or applications where precise speed control is needed throughout the entire operation cycle, as it is strictly a starting and stopping device.

Key specifications

• Rated operational current: 32A
• Motor power at 400V: 15kW
• Motor power at 230V: 7.5kW
• Operational voltage: 200-480V AC
• Control supply voltage: 110-230V AC/DC
• Size: S0

Installation should be performed by qualified personnel in accordance with the manufacturer's technical documentation. The device is mounted in the control cabinet and connected between the power supply and the motor. Ensure that the control voltage is correctly applied to the designated terminals to enable the soft start function. Once installed, the device operates automatically to manage the motor ramp-up based on the internal settings.

What to consider before purchase

• Verify that the motor power and current ratings match the device specifications.
• Ensure the control voltage supply is compatible with the unit.
• Check the available space in the control cabinet for proper ventilation.
• Confirm the application does not require high starting torque.

For optimal performance and longevity, ensure the soft starter is installed in an environment with adequate ventilation to prevent overheating. Regularly inspect electrical connections for tightness and ensure the device is protected against dust and moisture according to the required IP rating of your enclosure.