FAQs on refrigeration compressors, do you know these
1. Why control the impurity content and moisture content of the compressor and air conditioning system?
Impurities entering the friction surface of the moving parts of the compressor pump body will cause abnormal scratches and wear. Impurities entering the solenoid valve, expansion valve, control valve, capillary tube and stop valve in the refrigerator system will block the valve hole or The valve is not closed tightly and fails.
Compressor moisture mainly produces adverse effects in several aspects:
The capillary tube and expansion valve will cause ice blockage, and the evaporator cooling pipe will also freeze;
Metal materials are corroded, forming deposits;
The valve core is corroded and the closing is not tight;
The phenomenon of "copper plating" occurs on the surface of the compressor pump body parts;
Accelerate the deterioration of materials such as insulating materials, refrigerants, and refrigerating machine oils.
2. What impact will low voltage have on the air conditioning system?
If the voltage is too low, much lower than the specified operating voltage range of the compressor, because the locked-rotor current value may not reach the operating current specification of the protector, the protector will not operate in time, and the compressor motor will overheat or even burn out. .
3. What is the function and principle of the compressor protector?
The function of the compressor protector is mainly to protect the compressor from accidents such as burning of the motor when the compressor is in abnormal conditions.
The main principle is to rely on the internal heating wire of the protector and the internal resistance of the bimetallic sheet to actuate the bimetallic sheet through the combined action of current heating and external conduction heat, thereby cutting off the circuit and protecting the compressor from damage.
4. How to make basic judgment and handling after the compressor fails?
No suction and discharge pressure: first check the compressor wiring and pipeline connection, check the main and auxiliary coil impedance, compressor insulation pressure and other basic items. If everything is normal, it is recommended to remove the compressor to check whether there is suction and exhaust.
The method of suction and exhaust is: When the compressor is running, press your finger on the exhaust port for a few seconds, then release it to observe whether there is gas ejected. A small amount of oil ejected is normal. If there is suction and discharge, the discharge pressure is high, indicating that the compressor can work normally, otherwise the compressor is abnormal.
5. Why is it necessary to prohibit the reflux of liquid refrigerant from entering the suction chamber of the compressor?
If the liquid refrigerant directly enters the suction chamber of the compressor, during the crankshaft rotation, the compressor volume becomes smaller and smaller, and the pressure rises sharply, resulting in abnormal force or even damage to the pump body parts and valves. Liquid hammer can also cause abnormal vibration and noise of the compressor.
6. Why shouldn't the recovery time of air-conditioning refrigerant be too long?
The air conditioner should not be too long for refrigerant recovery operation. Because after the refrigerant recovery time is too long, the temperature of the exhaust gas will be very high because the refrigerant gas sucked in is extremely thin, causing the temperature of the pump body of the compressor to rise rapidly. Excessive temperature makes the expansion degree of each part differ too much, causing the fitting clearance of some parts to become smaller or even disappear, and eventually produce abnormal scratches or wear.
7. What is the impact of the wrong connection of the compressor? Why can't the protector protect?
The wrong wiring of the compressor will make it unable to work normally. According to different wiring errors, it will cause stalls, reverse rotation, stop after starting, etc., and it may cause the direct burning of the compressor motor.
Since the compressor protector is selected according to the compressor's correct wiring and the working characteristics of the protector under abnormal working conditions, it is impossible to ensure that the compressor will be protected when the wrong wiring is connected. In the case of wrong wiring, it is more difficult to protect the motor through the protector.
8. Do I need to adjust the system when changing compressors from different manufacturers for the same system?
As the performance characteristics of compressors produced by different companies are different, for a specific compressor, the best performance can be shown only under specific conditions such as refrigerant flow, suction and discharge pressure, and temperature.
Therefore, on the same refrigerator system, when using different compressors, it is best to adjust the system separately to ensure that the compressors used are working properly under the proper refrigerant flow, suction and discharge pressure, and temperature conditions, so that they can be effective. Extend the service life of the compressor and achieve the best results.
9. Why is there a requirement for the temperature of the compressor motor coil during operation?
The insulation grade of the insulating material used in the compressor motor (insulation grade: A (105°C), E (120°C), B (130°C), F (155 °C), H (175°C)) And heat resistance. For motor enameled wires, too high temperature will result in a decrease in the amount of film cocoon, friction resistance K drop, easy peeling, insulation breakdown voltage and insulation resistance K drop, etc., which will greatly reduce the service life.
In addition, the high temperature of the motor can cause too much dissolution of the high molecular substances in the insulating material. These substances will precipitate and accumulate somewhere in the system or at the compressor exhaust port, thereby affecting the performance of the compressor and the system. Also, excessively high coil temperature will reduce the efficiency of the compressor motor.
10. Why can the compressor be restarted after being shut down for at least 3 minutes after being shut down?
When the compressor starts, more refrigerating machine oil will enter the air conditioner system along with the refrigerant circulation. If there is not enough running time, [this article source: Refrigeration Encyclopedia Official Account], then the refrigerating machine oil will not return to the compressor cavity in time. Frequent starting and stopping soon after the start will result in low oil level inside the compressor, which is likely to cause poor lubrication of the mechanical moving parts of the compressor. In addition, the shutdown time of more than 3 minutes is mainly to give the system enough pressure balance time, otherwise the compressor will not start normally due to the existence of high and low pressure.
11. Why can't the compressor run under "vacuum conditions"?
The so-called "vacuum condition" is not an absolute vacuum state, but an extremely low pressure state, and gas molecules will ionize at extremely low pressure.
According to the actual experimental results, the compressor terminal has the lowest breakdown voltage when the compressor internal pressure is about 3.5mmHg, and it is prone to breakdown and internal carbon deposits when energized, which will damage the insulation of the sealed terminal and cause the compressor to operate under severe conditions. An accident occurred in which the sealing terminal was burnt out and flew out. Therefore, avoid energizing when the compressor is evacuated.
