Air dryer does not work at all

Cause one: The power supply is incorrectly connected or disconnected;
Cause two: The AC contactor coil is burned;
Cause three: The overload relay contacts are burnt out;
Cause four: High and low voltage protection switch contacts are burned;
Cause five: The fuse or no-fuse switch has tripped;
Cause six: The device start switch contact is open;
Cause seven: Poor contact of oil pressure switch and flow switch;
Cause eight: The high and low voltage protection is not reset after tripping;
Cause nine: The phase of the power supply is inconsistent with the phase of the compressor;
Cause ten: The internal programming of the smart relay failed.