Refrigeration compressor is the heart of the entire refrigeration system, is the most important in the refrigeration system, the main role is to compress the low temperature and low pressure gas from the evaporator into high temperature and high pressure gas, providing a source power for the entire refrigeration cycle. Household air conditioners are mainly used in rotor type, scroll compressor, this paper analyzes the two kinds of air conditioning in the daily maintenance of common faults and descriptions.
1. How to identify the 3 terminal posts on the fully enclosed compressor casing?
The resistance between the running end (R), the starter (S), the common terminal (C), and the resistance between RS is greater than the resistance between sc. The resistance between RS is equal to the resistance between SC plus the resistance between RC.
The above-mentioned laws can be used to distinguish them. It should be noted that the resistance value of the terminal block temperature rise tester of the three-phase compressor is equal.
2. How to judge the short circuit of the compressor motor winding?
Use the multimeter to select the resistance file, adjust the zero, and measure the resistance value of the compressor motor windings C-R or C-S. If the resistance value of the measured winding is less than the normal value, it can be judged that the winding is short-circuited.
Three-phase compressors:
The resistance measured twice is infinity, indicating that there is a set of windings that are broken;
All three tests were infinity, indicating that at least two sets of windings were broken;
In 2 of the 3 measurements, the resistance measured was significantly lower than that measured in the other, indicating a short circuit.
3. How to judge that the compressor motor touches the shell and passes through the ground?
Use the resistance file of the multimeter. Then close one pen to the common point, the other pen to the compressor process tube to expose the metal part, or a small piece of the patent leather of the housing plate to measure. If the resistance value is small, it can be judged that the winding or internal wiring is touching the shell to the ground.
4. How to judge the circuit break of the winding of the compressor motor?
Adjust the multimeter to the resistance file, connect the pen to the terminal of any two windings, and measure its resistance value. If the winding value is infinity, that is, the terminals of the two windings are not conducted between them, it can be judged that the winding is broken.
5. What does the compressor not start to check?
Check for compressor overload, pressure switches, and overcurrent protectors for jumping or damage.
Check the room thermostat and tube thermostat for open circuit or poor contact.
Check whether the relay is suctioned, whether the compressor is open or short-circuited, and the compressor capacitance is broken.
6. What are the reasons why the compressor overheats and causes the shutdown shortly after start-up?
Insufficient or excessive refrigerant, clogged capillary assemblies, and air leakage inside the 4-way valve.
The compressor itself fails, such as short circuit, broken circuit, shell through the ground, etc.
High pressure pressure is too high, pressure relay action.
The condenser is poorly ventilated or short-circuited, or the system is mixed with non-condensate gases.
The ambient temperature of the outdoor unit is too high.
Compressor snap cylinder or grip shaft.
7, the compressor efficiency is low performance
It is generally manifested as a decrease in exhaust pressure, an increase in suction pressure, and an excessive temperature in the compressor cylinder head and suction and exhaust chamber.
8, the compressor lost the ability to work judgment
First test whether the suction port has inhalation, and then test whether the exhaust port has exhaust, block the exhaust port with your hand, if you feel that the pressure is not very large, or even no exhaust, you can think that the compressor loses its working ability.
9. Why is the compressor motor too current too large?
The compressor is short-circuited between turns, but not to the point of blowing the fuse. The "secondary friction" of the compressor destroys the finish of the friction surface, resulting in an increase in the power and current of the compressor, but it has not yet reached the degree of "holding the shaft" or "jam cylinder", so that the compressor cannot rotate.
Use a multimeter to check the compressor's insulation resistance to ground, under normal circumstances, it should be above 2MΩ, such as becoming smaller or close to zero, indicating that it has been short-circuited. If the insulation resistance to ground is normal, check the resistance value of the starting and operating windings. If the inter-turn circuit is shorted, the operating current increases.
10. What is the reason for the difficulty of starting the three-phase compressor motor?
The power supply voltage is too low, the compressor motor windings are short-circuited, or the compressor cylinder is stuck.
11. How to eliminate the failure of the three-phase compressor motor that slows down in operation, the fuse of one phase is broken, and the current of one phase increases?
It is often caused by the compressor motor windings having a phase bumping shell through the ground. After removing the ground wire, you can use a test pen to measure whether the machine case is charged. If the enclosure is charged, rewind the compressor motor winding or replace the compressor.
12. How to exclude the three-phase compressor motor from emitting a "stinging" sound during operation?
The three-phase compressor motor emits a "sting" in operation, which is caused by the serious imbalance of the three phases, and there is a lack of phase for one phase of the power supply, and the three phases can be restored.
13. How to exclude the reversal of the three-phase compressor motor?
It is caused by a wiring error, and it is enough to arbitrarily swap two of the three phases.
14. Compressor replacement sequence and points of attention
R22 is a non-combustible gas, but when it comes into direct contact with a high-temperature flame, it will produce a toxic gas, so the refrigerant in the refrigeration system is released before the welding operation.
R32 is a flammable and explosive refrigerant, and we have repeatedly emphasized the characteristics of this refrigerant. Where R32 refrigeration equipment involves refrigeration system maintenance and needs to replace accessories, it must be vacuumed before operation! Be careful not to introduce fire sources!
R410A low toxicity, non-combustible and non-explosive, replace the compressor must use R410A special compressor, absolutely can not use R22 compressor installation. When replacing valves, the R410A has a special marking on the body
15. What are the types of air conditioner compressor overload protectors?
External overload protector;
Embedded overload protector.
16. What is the protection of the compressor?
Overload protector: Mainly used for overcurrent and overheat protection of compressor motors.
Internal protector: Mainly overcurrent protection of the compressor motor.
Thermal relay: Mainly used for line overcurrent protection of three-phase compressor motors.
Reversing phase preventer: Mainly used for three-phase rotary compressor machine to prevent the compressor rotation direction from reversing phase or lack of phase energy.
17. What are the common causes of overload protectors?
The supply voltage is too low and the symmetry of the three-phase voltage is poor.
Compressor motor extended time running at low speed.
Compressor motors operate at low voltage with load for a long time.
The compressor motor cooling medium path is blocked.
The ambient temperature is too high for use.
18. What is the hydraulic strike of the compressor?
The refrigerant does not completely evaporate in the evaporator, causing the refrigerant to be sucked back by the compressor in a wet vapor or liquid state, causing the compressor to hit the liquid. Hydraulic shock can cause valve plates, valve plates, pistons to be broken and damaged, and in severe cases, the connecting rod may also be deformed, and even the compressor can be damaged. #压缩机 #