Analysis of Various Causes of Damage, Burnout, and Non operation of Electric Scroll Compressors and Suggestions for Standardized Installation

The following problems may occur with various exceptions:
1. Abnormal compressor operation sound
2. Compressor chamber temperature too high
3. The scroll plate is broken and debris scratches the insulation layer of the motor coil
4. Exhaust or top temperature too high, compressor chamber temperature too high
Possible causes of problems for reference:
1. Frequent startup and shutdown of the compressor: During static state, oil and refrigerant deposit in the compressor chamber, and during startup, the oil is discharged from the compressor together with the refrigerant. If the operation time is not long and the compressor is stopped, the oil cannot return to the compressor in time. After repeated operations, the compressor eventually burned out due to lack of oil;
2. The system contains air or water: When the compressor operates at high temperature and pressure for a long time, the lubricating oil begins to acidify and heat up, eventually turning into colloidal substances, causing the compressor to jam;
3. System return or refrigerant migration: May dilute the lubricating oil, which is not conducive to the formation of oil film, leading to insufficient lubrication;
4. System refrigerant leakage: may cause lubricating oil leakage, making the compressor less lubricating oil;
5. Reverse rotation of the compressor (such as phase sequence error): making it impossible to establish the internal pressure difference of the compressor, resulting in the inability of lubricating oil to be delivered to various friction surfaces;
6. Impurities entering the system: Impurities entering moving parts such as scroll plates and crankshaft sleeves can cause wear, which may cause high temperature and oil deterioration, and the deterioration of lubrication effect may cause increased wear and deterioration;
7. Incomplete refrigerant evaporation: Common causes include non rotating internal fan, low air volume, blocked air duct, dirty filter screen or heat exchanger, etc;
8. Multiple indoor units do not have unified power supply: the EXV valve of the indoor unit that is suddenly powered off still maintains a certain opening, but the fan does not operate, and a large amount of refrigerant directly returns to the compressor without evaporation;
9. Excessive refrigerant addition: leading to a large amount of liquid return in the system (low temperature environment, low load refrigeration and low temperature heating are more likely to occur;
10. Excessive oil addition: resulting in system oil shock (rare occurrence): For high-pressure chamber compressors, too much lubricating oil can lead to increased motor rotational resistance, increased input power, and poor motor heat dissipation;
11. Insufficient refrigerant addition or refrigerant leakage: resulting in excessively high exhaust gas temperature;
12. Dirty or ice blockage of the system (ice blockage mainly refers to the return pipe): resulting in excessive exhaust or top temperature;
13. Insufficient system vacuum: compressor compresses air, pressure ratio is too high, temperature is too high;
14. The operating environment of the system is harsh: the air duct is blocked, the return air is poor, and the heat exchanger is dirty, resulting in cold
The condensation pressure is high and the exhaust temperature continues to rise;
15. The connecting pipe is too long or the pipe diameter is too small: the system resistance increases, resulting in an increase in exhaust temperature and pressure;
16. Abnormal wear of the compressor caused by various reasons may cause the worn metal chips to damage the insulation layer of the coil and burn down the motor;
17. The burning or abnormality of the contactor contacts (such as lack of phase or phase deviation) will directly affect the compressor motor;
18. Power supply phase loss or voltage abnormality: the variation range of power supply voltage cannot exceed ± 10% of the rated voltage, and the voltage imbalance rate between three phases (380V) cannot exceed 3%; When the voltage is unbalanced, the load current is 44-10 times that of normal operation;
19. Insufficient cooling of the motor: When a large amount of refrigerant leaks or the evaporation pressure is too low, the system mass flow rate will decrease, making the motor unable to obtain good cooling. Frequent protection will occur after the motor overheats.
Practitioners standardize installation during maintenance and assembly
1. Before installation, the copper pipe shall be subject to dustproof and waterproof treatment to prevent impurities and moisture from entering the refrigerant pipeline and compressor.
2. Use special tools to cut copper pipes (cutting knives) to avoid copper chips entering the pipeline when cutting copper pipes with a hacksaw or other tools.
3. Use nitrogen protection during pipeline welding to prevent welding slag and oxide skin from entering the refrigerant pipeline.
4. The indoor units of the same system are powered uniformly to avoid direct power failure of some internal units causing refrigerant liquid shock.
5. The multi on-line indoor unit shall not be used as an air conditioner in the machine room to avoid long-term low load operation of the external unit or frequent startup and shutdown leading to compressor oil shortage.
6. The size of the air outlet grille of the indoor unit should be matched, and the filter screen should be cleaned regularly to avoid air flow reduction and incomplete refrigerant evaporation due to small size or misalignment of the grille or installation, or excessive dirt on the filter screen.
7. Calculate the refrigerant addition amount according to the standard, and use an electronic scale to add to avoid liquid hammer or excessive refrigerant temperature caused by excessive or insufficient refrigerant amount.
8. Pay attention to the power supply voltage of the air conditioning system and standardize the power wiring to avoid large current generated by the compressor due to unstable power supply voltage, three-phase voltage imbalance, and lack of equality.
9. Pay attention to horizontal placement of branch pipes for parallel connection of outdoor units to avoid uneven distribution of refrigerant and oil between outdoor unit modules, resulting in excessive or insufficient refrigerant/oil content in some outdoor units.