Soft starters

Soft starters are motor control devices used to gradually ramp up the voltage applied to an electric motor during startup. Unlike traditional direct-on-line starters that apply full voltage instantly, soft starters mitigate the initial high inrush current and torque, protecting both the motor and the connected mechanical system.

These devices, often categorised alongside Variable Speed Drives (VSDs), offer a cost-effective solution for applications where full motor speed is required but the impact of a sudden start needs to be minimised. Soft starters control the voltage applied to the motor, typically using thyristors or triacs, allowing for a smooth and controlled acceleration.

EATON offers EATON DS7 range of soft starters covering various motor power requirements, with ampere ratings from 4A, 7A, 9A up to 32A. Many of these units boast an IP20 rating, indicating protection against solid objects larger than 12.5mm. Their product portfolio includes soft starters suitable for motors up to 75kW, 55kW, and even larger units reaching 560kW and beyond, catering to diverse industrial needs.

Key Features

Controlled Startup: Gradually increases voltage to the motor.
Reduced Inrush Current: Minimises peak current draw during startup.
Torque Limitation: Reduces initial mechanical stress.
Ampere Range: Available from 4A, 7A, 9A up to 32A.
IP Rating: Many units feature an IP20 rating.
Power Range: Suitable for motors up to 75kW, 55kW, 560kW and more.

Benefits and Applications

The benefits of using soft starters include reduced mechanical stress on equipment, minimised electrical disturbances on the power supply, and decreased wear and tear on the motor, leading to extended lifespan and reduced maintenance.