Siemens 3RW3018 Soft Starter, 7.5 kW at 400V, 4 kW at 230V, 17.6 A Rated Current

The Siemens 3RW3018 soft starter is a high-performance control device engineered for the controlled starting and stopping of three-phase asynchronous motors. By regulating the voltage supplied to the motor, this unit ensures a gradual acceleration, which effectively prevents mechanical shocks and electrical surges that are common during direct-on-line starting. Its compact design makes it an ideal solution for space-constrained industrial control cabinets, providing a reliable method to extend the service life of motors and connected mechanical components like belts, gears, and couplings.

Advantages

The primary benefit of using this soft starter is the significant reduction of mechanical stress on the entire drive train, which leads to lower maintenance requirements and fewer equipment failures. By minimizing current peaks during the startup phase, the device helps maintain the stability of the power supply network and prevents voltage drops that could affect other sensitive equipment. The unit is designed for efficiency and ease of integration, offering a robust solution that balances performance with operational longevity in demanding industrial environments.

Suitable for

• Conveyor belt systems
• Pumps and hydraulic systems
• Fans and ventilation units
• Compressors
• Small industrial machinery

When it may not be suitable

This soft starter is not intended for applications requiring high starting torque, as it reduces voltage to achieve a smooth start. It is also not suitable for frequent switching operations or heavy-duty starting cycles that exceed the thermal capacity of the device.

Key specifications

• Rated operational power: 7.5 kW at 400V, 4 kW at 230V
• Rated operational current: 17.6 A
• Control supply voltage: 110-230V AC/DC
• Device size: S00
• Compatibility: Three-phase asynchronous motors

How to use

Installation should be performed by qualified personnel in accordance with local electrical regulations. The soft starter is mounted on a standard DIN rail within a control cabinet. After physical installation, connect the power supply lines to the input terminals and the motor leads to the output terminals. Ensure the control voltage is correctly wired to the designated terminals. Once powered, the device manages the ramp-up process automatically based on its internal settings, providing a smooth transition to full operational speed.

What to consider before purchase

• Verify that the motor power and current ratings match the device specifications.
• Ensure the control voltage matches your existing control circuit.
• Check the available space in your control cabinet for proper ventilation.
• Confirm the application does not require high starting torque.

Usage recommendations

Always ensure proper ventilation around the soft starter to prevent overheating during operation. Regularly inspect electrical connections for tightness to maintain optimal performance and safety.