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Technical details

230-460 V, three-phase

Soft starter sizing guide

Soft starter sizing guide

Fairford have 4 different classes to choose the right softstarter for motor application:

  • Soft start (trip class 2): 3x FLC for 5s
  •  Standard start (trip class 10): 3x FLC for 23s/ 3.5x FLC for 17s
  •  Middle heavy start (trip class 20): 4x FLC for 19s
  • Heavy start (trip class 30): 4x FLC for 29s

Typical representatives of each class are:

  • Easy start: Compressors, mixers and conveyor belts that start unloaded (standard load is available if load is possible)
  • Standard start: Fans (low inertia), pumps, partial compressors,…
  • Moderate start-up: compressors, larger fans, heavy conveyor belts,…
  • Hard start: mills, crushers,…

After selecting the appropriate class, select soft start according to the motor power on the table below.


  • DFE-02
  • DFE-04
  • DFE-06
  • DFE-08
  • DFE-10
  • DFE-12
  • DFE-14
  • DFE-16
  • DFE-18
  • DFE-20
  • DFE-22
  • DFE-24
  • DFE-28
  • DFE-30
  • DFE-32
  • DFE-34
  • DFE-36
  • DFE-38
  • DFE-40