Trouble shooting of electromagnetic clutch of automobile air conditioner

The air conditioning electromagnetic clutch coil is burnt. In addition to the quality problem, the main reason is that the pressure of the air conditioning system is too high and the resistance driving the compressor to run is too large, which exceeds the electromagnetic attraction of the electromagnetic coil, causing the relative sliding friction between the active and passive discs of the clutch, resulting in overheating and burning.

There are three reasons for the high pressure of the air conditioning system:

① When stopping, the engine runs at idle speed and the air conditioner is used in the sun for a long time;

② When the radiator fan of the water tank fails, the air conditioner is used for a long time and with high intensity (the radiator fan of the water tank is shared with the condenser fan of the air conditioner);

③ Excessive Freon is added to the refrigeration system.

When the compressor starts to work, pay attention to the observation window of the liquid storage tank. It is found that there is no bubble in the observation window. Then connect the high and low pressure gauges to the refrigeration system and check the pressure. It is found that the pressure at the high pressure side and low pressure side deviates. Obviously, the refrigerant is overfilled. After removing a proper amount of refrigerant from the low-pressure side (the pressure at the high-pressure side is 1.2-1.8MPa, and the pressure at the low-pressure side is 0.15-0.30MPa), the fault is eliminated.

In order to avoid such failures, air conditioners shall not be used under the following three conditions.

① If the amount of refrigerant exceeds the specified amount, it shall be discharged in time, otherwise the air conditioner shall not be used. The method to check the amount of refrigerant is: when the compressor starts to work, check whether there are bubbles in the observation window of the liquid storage tank. If there are no bubbles, it means that there is too much refrigerant, which should be released appropriately. If there are too many bubbles, it means that there is too little refrigerant, which should be added appropriately.

② When the radiator fan of the water tank stops running due to failure, the air conditioner shall be stopped immediately, otherwise the refrigeration system will generate ultra-high pressure, which will cause the electromagnetic clutch to slip and burn.

③ When parking, it is better not to turn on the air conditioner when the engine is idling.