What is a Softstarter?

The original definition is a reduced torque starter. The industry short hand refers to a soft starter as a solid state reduced voltage starter where a voltage limit is applied to the motor during starting. The key thing to remember in operation is reduced voltage equals reduced torque equals reduced current. The major differentiating factor between a soft starter and an AC drive (VFD) is that the soft starter only affects voltage where a VFD affects voltage and frequency.

The benefits of soft starters can be broken down into electrical and mechanical benefits:

Electrical Benefits:

  • Reduces voltage drops on network
  • Minimizes starting currents
  • Eliminates current spikes
  • Allows optimization of cabling

Mechanical Benefits:

  • Minimizes stress on transmissions like gearboxes, belts and bearings
  • Minimizes maintenance time and cost, extends the life of the equipment
  • Limits the pressure waves in pump systems (i.e. water hammer)