What is a soft starter?

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What is a soft starter?

The first question is: what is a soft starter? Simply put, a soft starter is an electronic device which controls the acceleration of an electric motor, in order to greatly reduce the starting current and associated side-effects of direct motor starting.

How does it work?

Most electronic soft starters work by using internal circuitry to regulate the voltage supplied to the motor. By gradually applying more voltage, the motor starts slowly and gracefully and draws much less current while starting (2-3 times the normal running current instead of 7-10 times for a directly started motor). The starting time is often adjustable by the operator. In addition, many soft starters also include a soft stopping feature – the reverse of soft starting.

Why use a soft starter?

There’s a number of applications where an electronic soft starter can be very useful:

  • To greatly limit current spikes from starting motors, where limited electrical supply capacity is available
  • To ease starting of conveyors, belts or mechanical systems to minimise tension, slipping and jerking
  • To reduce pressure spikes and hammering in pumping systems
  • To reduce voltage drops in applications where stable voltage is important