Case analysis of maintenance of central air-conditioning compressor

Case analysis of maintenance of central air-conditioning compressor We all know that the compressor is the heart of the refrigeration system, and it can be said to be the lifeblood of the refrigeration system. The compressor often has various problems during long-term use. Today, the editor mainly wants to explain the maintenance case of Daikin central air conditioning compressor. . In order to give you a reference, the article is compiled from the Internet.

　　 1. Compressor vibration and noise

　　Fault analysis: Vibration and noise are important indicators for evaluating compressor performance. Vibration and noise mainly come from the following aspects:

　　1. Noise caused by unbalanced mass distribution of mechanical operating parts inside the compressor.

　　2. The impact and vibration of the airflow during inhalation and exhaust.

　　3, the magnetic field vibration and rotation vibration of the motor.

　　4. The stirring sound when the refrigerating oil is rotated at high frequency.

　　 5. The sound of the main bearing, the sound of the shaft and the sliding part.

　　 6, the resonance of the exhaust pipe and the air column in the compressor casing.

　　7. The impact of the compressor and the shell wall, the sound of the shell itself, and the impact of the support spring.

　　Removal method: For the above various reasons, the compressor noise generated by the interleaving can be reduced and eliminated from the following aspects.

　　 1. The moving parts shall be measured for dynamic balance and static balance.

　　2. Choose reasonable intake and exhaust pipes, especially the position, length, and pipe diameter of the intake pipe have a great influence on the performance and noise of the compressor, and the airflow is prone to resonance.

　　3. The structure, shape, wall thickness, material, etc. of the compressor housing are directly related to the noise reduction effect. Therefore, in order to reduce noise, the shell wall can be thickened appropriately.

4. During installation and maintenance, if the bending radius of the connecting pipe is too small or flat, the opening gap of the stop valve is too small, the system is blocked, and the pipe used for connection does not meet the requirements (the specifications are too thin and too short), these factors will Increase running noise.

　　5. The refrigerating oil of the compressor should be appropriate. A large amount of oil can enhance the lubrication effect, but it increases the sound of the internal parts stirring the oil. Therefore, the oil circulation in the refrigeration system must not exceed 2%.

　　6. ​​Choose a reasonable bearing clearance. In the case of good lubrication, a smaller fit clearance can be used to reduce noise.

　　7. The insulation and shock-absorbing cushion between the outside of the compressor and the pipeline must meet the requirements.

　　 2. Repair of broken compressor suction and exhaust pipes

　　During the use of air conditioner, due to vibration and environmental corrosion, the compressor suction pipe or exhaust pipe is broken and rusted is one of the common faults. The following methods can be used to repair

　　 Treatment method: first make a red copper pipe sleeve, the inner diameter of the sleeve should be slightly larger than the outer diameter of the compressor suction and discharge pipe. Remove the compressor from the air conditioner. Wipe clean the broken pipe opening and the surrounding area, and scrape off the paint and oxide layer. Do not cut the remaining part of the pipe, and for the rusty pipe, remove the leak (be careful not to let the frozen lubricant in the compressor flow out), and then wrap the compressor with a damp cloth to prevent burning during welding Bad paint layer on the shell. When welding, the casing is welded to the compressor shell first, and then the boiler tube and the casing are welded. Finally, leak detection is performed.

　　 Three, winding short circuit fault handling skills

Due to the damage of the winding insulation layer, a short circuit between adjacent coils occurs, which instantly increases the current and even burns the motor. For single-phase motors, first remove the external wiring of the motor, and then use a multimeter to electrically block the test C, S and c, R The resistance value between the terminals, if the measured resistance value of a certain winding is less than the normal value, it means that the winding has a short circuit, and the short circuit should be replaced; for a three-phase motor, use a multimeter resistance R×10 block resistance to measure each adjacent two The resistance between two terminals; if the resistance values ​​are equal, it means that the three-phase motor is good; if there is a small resistance between a pair of terminals, it means that this group of windings has a short circuit; if there is a pair of wiring The resistance between Gui is infinite, indicating that the winding has been blown,

　　Troubleshooting skills for winding open circuit:

　　 Due to the serious short circuit. The current is too large and the winding wire is burned. When checking, the external wiring of the compressor motor should be removed first, and the resistance between the c, R and c, s terminals should be measured. If the resistance is infinite, it means that the winding group has been disconnected and should be tragically restored.