1, winding short circuit, open circuit, winding touching the casing and grounding: these faults are all caused by the motor part of the compressor. When the circuit is open, the power supply is normal and the compressor does not work; In case of short circuit and shell collision, the protector acts after being energized, or the fuse is blown; If the winding turns are slightly short-circuited, the compressor can still work, but the temperature of the compressor is very high and the working current is very large. After work, the thermal protector will act soon. Generally, a multimeter can be used to check the winding open circuit and the winding grounding of the contact sleeve. The winding is slightly short-circuited, so it is difficult to judge. It should be judged according to the measured current.
2. Vibration and noise of compressor: This often happens during maintenance. Generally, the refrigeration performance has little influence, but users feel abnormal, mainly because the pipeline collides with the casing, the damping block falls off and the compressor fixing bolt is loose.
3. The compressor suction and exhaust valves are not closed properly: the compressor suction and exhaust valves are damaged, and even if the refrigerant is sufficient, the system cannot establish high and low pressure or it is difficult to establish qualified high and low pressure, and the system does not cool or the cooling effect is poor.
4. The compressor shaft and cylinder are stuck: the main fault is that oil is lost or impurities enter, the compressor does not run after being electrified, and the protector acts.
5. Damage of thermal protector: generally, the operating temperature point becomes smaller or the circuit is broken. Open circuit will cause the compressor not to work; When the working temperature point becomes smaller, the compressor will stop after working for a period of time, which is easy to be confused with a slight short circuit between windings. It can be distinguished by the normal working current when the thermal protector is damaged and the excessive current when the winding is short-circuited.