Cause Analysis
1. The power supply is out of phase or the voltage exceeds the allowable range
2. Incorrect wiring
3. The relay or contactor does not pull in
4. If the compressor starts with a capacitor, the starting capacitor will be damaged
5. Poor high and low voltage protection switches

6. Mechanical failure of the compressor, such as stuck cylinder,

Solution:
1. Check the power supply, make the power supply voltage within the rated range
2. Check the circuit according to the circuit diagram
3. Check the cause, replace or repair
4. Replace the starting capacitor
5. Adjust the setting value of the pressure switch, or replace the pressure protection switch
6. Replace the compressor