According to statistics, in the first half of a year, users complained about a total of 6 compressors. User feedback said that the noise is one, high current five. The specific reasons are as follows: One unit due to water enter into the compressor, Five units due to insufficient lubrication.
Poor lubrication caused compressor damage accounted for 83%, we find out two of the situations to give you list.
User feedback said that compressor can’t start, and current is high.
Inspection process:
- Electrical performance test, found that all within the normal range, judge electrical performance qualified. Electrical performance test items are: respectively test the electrical resistance, leakage current, insulation resistance, electrical strength, grounding resistance value of three items of the motor.
- Observe the color of compressor oil and find oil pollution;
- Running test, unable to run;
- Compressor disassembly, as shown in the figure below:
Static/dynamic vortices are normal
Dynamic scroll bearing, shaft sleeve serious wear
The motor upper part is normal
Potential cause analysis:
The electrical performance of the compressor was qualified at the initial test, but it could not be started. The dismantling test found that the moving scroll bearing was severely worn and locked, which indicates that the compressor was in poor lubrication state before failure. So the potential cause:
There is liquid in compressor when starting:
When the system down state , there are too many refrigerant back inside of compressor, when the compressor starts up again, the refrigerant liquid will instantaneous evaporation deposition in oil and produce large amounts of foam, the foam filled and blocks the oil channel, especially top way can not supply oil normally and cause the wear.
Suggestion of preventive measures:
The system is recommended for screening. For example: check whether the return oil of the system is normal; Check the refrigerant charging amount of the system to avoid overcharging; Check system refrigerant charging operation, the correct charging position should be selected between the two devices, etc.
User feedback said that compressor can’t start.
Inspection process:
- Electrical performance test, found that electrical properties unqualified.
- Observe the color of compressor oil and find oil pollution
- No operational tests.
- Compressor disassembly, as shown in the figure below:
Main bearing, main bearing sleeve wear seriously
The motor was partially burnt out and the frozen oil was polluted
Potential cause analysis:
The electrical performance of the compressor was not qualified in the initial test, No running test. Disassembly test found slight wear of moving scroll bearing, slight wear of moving scroll shaft sleeve, severe wear and embrace of main bearing, severe wear and embrace of spindle sleeve. So the Potential cause are:
`There is liquid in compressor when starting:
When the system down state , there are too many refrigerant back inside of compressor, when the compressor starts up again, the refrigerant liquid will instantaneous evaporation deposition in oil and produce large amounts of foam, the foam filled and blocks the oil channel, especially top way can not supply oil normally and cause the wear.
`Excessive return liquid:
when the compressor is running, excessive refrigerant liquid is transferred back to the compressor, which dilutes the lubricating oil inside the compressor, resulting in the decrease of lubricating oil concentration and the failure to ensure the normal lubrication of the bearing surface, resulting in wear.
Suggestion of preventive measures:
Recommend system screening, such as:
Check whether the oil return of the system is normal;
Check the refrigerant charging amount of the system to avoid overcharging;
Check system refrigerant charging operation, the correct charging position should be selected between the two devices;
Check the type selection and working state of the expansion valve of the system. If the expansion valve is unstable, it will cause liquid return.
Check if there are any protective devices to prevent the return of refrigerant, etc.
Among them, 17% of the compressor is damaged due to excessive moisture, and the customer feedback noise is large.
Inspection process:
· According to the customer feedback problems of the compressor do electrical performance testing, found that all within the normal range, judging the electrical performance qualified.
Test items as above.
· Observe the color of compressor oil and find oil pollution.
· During the operation test, it was found that there was no obvious noise, but it was disassembled because the oil was polluted, as shown in the figure below:
Copper plating is found in moving scroll slider and lower shaft
The lower bearing surface is copper-plated and the oil is badly deteriorated
Potential cause analysis:
Disassembling and testing found obvious copper plating on the surface of most parts of the compressor.
It indicates that the moisture content in the compressor is too high, and water will acidify with lubricating oil, refrigerant and metal under the action of high temperature. The form of acid formation is copper plating, Acid will cause damage to mechanical parts, leading to bearing wear, serious damage to the motor will cause winding damage and burn out
Suggestion of preventive measures:
It is recommended to confirm the vacuum degree of the system and to ensure the quality and purity of refrigerant, while avoiding long-term exposure to air during assembly and replacement of the compressor.
Post time: Jul-10-2019
