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Refrigeration Compressor Starting Unloader

  • At a star-delta start of electric motors it is often considered necessary to limit the compression work of the machine at the starting moment in order to reduce the starting torque of the electric motor. 
  • Usually, a solenoid valve is used in a by-pass arrangement which in the starting up phase short circuits the discharge side to the suction side of the compressor.
  •  At the same time, a non-return valve must be fitted in the discharge line to the condenser preventing the return flow of discharge gas to the compressor.
  • When the electric motor has reached its max. number of revolutions per minute, a switch takes place from star to delta start. 
  • The solenoid valve is closed and the compressor now works under normal conditions.
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