How To Diognose and Open Compressor Winding, Single Phase

A PSC motor will not start with an open winding.  It may hum until the internal overload trips.

  • Disconnect the power to the unit
  • Discharge the capacitors
  • Disconnect the wires from the compressor terminals
  • Set your multimeter to low ohms
  • If you detect no Ohms reading from the start to common or reading from the run to common,you have an open overload or winding.
  • Check the resistance between the run and start terminal.  If there is resistance, the overload is open
  • If there is no resistance, you have an open winding.