To put it simply, there are three reasons for the overcurrent of the compressor:
The condensing pressure of the refrigeration system is too high;
Too much refrigerant in the refrigeration system;
The compressor lacks refrigeration oil;
Let's break them down separately:
1. Poor heat dissipation of the external unit
(1) Short circuit of the external unit return and exhaust: If the external unit is installed in a closed balcony, in a narrow aisle, in an unventilated place such as the house, there are obstructions in front of the tuyere.
(2) The air volume of the external unit is small, and the heat dissipation speed is slow: if the condenser of the external unit is too dirty or blocked by dust and oil, the fan motor speed is slow, the fan capacitance becomes smaller, and the temperature around the external unit is high.
2. External power supply voltage factor
The power supply voltage is low or high, both of which will cause the compressor working current to be high, and the domestic voltage is low to account for the vast majority, especially during the peak of electricity consumption.
(1) If the power supply voltage (i.e. the voltage before start-up) is too low, the user should be asked to re-wiring, if the voltage is about 190V, you can consider installing a voltage regulator, if it is too low, it will be invalid.
(2) Check the voltage drop after starting, under normal circumstances, the voltage drop is only more than ten volts, and the pressure drop is too large (it is recommended that the voltage drop is more than 20V and the voltage is 190V lower after the compressor starts), the power cord should be thickened or rewired, and the fault such as poor line contact should be eliminated.
3. Refrigeration system failure
(1) Mixed air in the refrigeration system: if there is air in the system, the air is often accumulated in the upper part of the condenser, because it cannot pass through the liquid accumulation device of the condenser, whether there is air in the system, generally can be determined by the beating of the system pressure, if there is air in the system, it should be re-evacuated and fluoridated.
(2) Excessive fluorine: The compressor is in a state of overload for a long time, which will eventually lead to the overcurrent of the compressor and jumping. In this case, part of the fluorine should be released to the standard range (the inspiratory pressure is about 0.5MPa at an ambient temperature of 35 degrees).
Fourth, the shell/internal temperature is high
(1) Poor lubrication of the compressor: the height difference between the indoor and outdoor machines is greater than 5 meters without making an oil return bend, or only making an oil return bend on a pipe, the system can not return oil smoothly, and the temperature of the compressor slowly rises during operation due to lack of lubrication, and finally leads to overheating and jumping.
For example, the outdoor unit is underneath and the heating is running, under this working condition, the gaseous working fluid flows upward in the thick pipe, and the liquid working fluid flows downward in the thin pipe, so the oil return is poor. The outdoor unit is on it, the heating is transferred, the gaseous working fluid flows downward in the thick pipe, and the liquid working fluid flows upward in the thin pipe, so the oil return is better.
The situation is the opposite of the above when refrigerating, there are two kinds of oil return bends: U-shaped and S-shaped, S-shaped can be added to the middle part of the connecting pipe, U-shaped is generally close to the machine installation, and the radius should be as small as possible.
(2) Too much impurities and moisture in the system: the lubricating oil deteriorates and carbonizes, and cannot play a normal effect, resulting in a sharp rise in the temperature of the compressor and overheating and jumping.
This situation generally occurs on machines that have been repaired or used for a long time, and if the substances in the inspection system are black, then this must be the case, at this time, nitrogen should be used to clean the system, replace the compressor, capillary assembly, and re-evacuate and add fluorine.
(3) Air conditioning is often used in an environment below 0 degrees: the lubricating oil bubbles during the compressor start-up time, so that a large amount of lubricating oil flows out of the compressor instantly, at this time, no matter how good the system design is, the speed of oil return is much lower than the oil discharge speed, and the compressor lacks lubrication to cause temperature rise and overheating protection.
In this case, an oil heater (40W---60W, 220V) should be installed on the compressor, and when the compressor is stopped, continue to keep the oil heater energized.
Fifth, the cooling effect of the compressor is not good
If the fluorine is too little, the system flow rate is small, which can not meet the 100% load of the evaporator, resulting in the increase of suction superheat, coupled with the small suction flow rate of the compressor, the cooling efficiency is greatly reduced, so that long-term operation can lead to compressor thermal protection.
