Common failures and maintenance of overload protectors for air-conditioning compressors

Common failures and maintenance of overload protectors for air-conditioning compressors Overload protector of air conditioner compressor Installed between the active and passive sides of the power transmission, when an overload fault occurs (torque exceeds the set value), the torque limiter will separate, thereby effectively protecting the driving machinery and the load. Just like its name, the fundamental function of the overload protector is to protect the air-conditioning compressor. Common failures of overload protectors include: heating wire burnout, contact burnout, contact break after the change of stress in the bimetallic sheet cannot be reset, insulation damage of the embedded overload protector and contact failure. The causes of overload are: (2) The source voltage is too low and the symmetry of the three-phase voltage is poor. ⑶ The air conditioner compressor motor runs at low speed for an extended period of time. ⑷Long-term low voltage and load operation of air conditioner compressor motor. ⑸ The cooling medium passage of the air conditioner compressor motor is blocked. ⑹ The ambient temperature is too high. Check the overload protector with a multimeter. Under normal circumstances, there should be a resistance value of tens of ohms. If the resistance value is infinite, it means that the overload protector is open. After the overload protector fails, except for poor contact and contact adhesion can be repaired, other failures are generally not repaired, only replaced and updated. After the built-in overload protector breaks down, it is generally difficult to repair or replace. It can only be replaced together with the air-conditioning compressor. In three-phase air-conditioning compressor motors, the three-phase overload protectors used are mostly bimetallic. The bimetallic element is connected in series with the contactor coil and low-voltage (24V) line of the air-conditioning compressor. The electric heating wire is connected in series with the compressor contactor and the motor connector (in the power circuit). When the metal sheet feels overheating or overcurrent, the bimetallic sheet can cut the motor circuit of the compressor. The above is the overload protector of the air conditioner compressor