When the compressor has a problem, the refrigerant in the refrigerator line cannot be operated normally, resulting in failures such as the refrigerator cannot be cooled, the refrigeration effect is poor, and there is noise during operation. Let's take a look at how to test a compressor.
1. Judge the compressor failure by sound
Listen carefully to the sound it emits while the compressor is running, and according to the sound, you can make a general judgment on the working state of the compressor or its own performance. For specific discrimination methods, please refer to the following phenomenon.
Relatively small "buzzing" sound: the compressor mechanical parts are normal.
No "buzzing" sound is heard: the compressor is damaged or there is a problem with its power supply circuitry.
Strong "buzzing" sound: the compressor does not start when it is energized, which is mostly caused by the compressor jam cylinder or the shaft.
There is a "tom" sound: a large amount of refrigerant wet vapor or refrigeration oil enters the cylinder.
There is a "dang" sound: the internal moving parts appear loose.
There is a "hissing" sound: the sound of high-pressure air flow when the high-pressure pipe in the compressor breaks.
If the running sound of the compressor is abnormal, in addition to the jam cylinder, the shaft fault can be repaired by some methods, and other faults can only be repaired by replacing the compressor.
2. Repair the compressor's jam cylinder and shaft failure
The card cylinder and the shaft holding are one of the common faults of the compressor, and when it is serious, due to the blockage, it may lead to a rapid increase in the current and the motor can be burned. For the phenomenon of slight jamming cylinder and shaft holding, the failure is discharged by tapping the compressor shell, and the specific maintenance method can be found in the following illustration.
Before plugging in the power, gently tap the compressor shell with a mallet or rubber hammer and constantly change the position of the hit. After plugging in, continue to gently tap the compressor housing and change the tapping position until the fault is ruled out. If the tapping does not work, the compressor needs to be replaced.
3. Detect the winding resistance of the compressor
If the compressor cannot start the work, it is necessary to use a multimeter to detect the resistance value of the winding of the compressor motor to determine whether the compressor motor is faulty. For more information about detection methods, see the following illustration.
The red and black pens of the multimeter are placed on either two winding ends of the compressor to detect the resistance between the windings of the compressor. Normally, the resistance between the starter and the operating end is equal to the sum of the resistance between the common and the starting end and the resistance between the common and running ends.
The above is the detection method and judgment result of the motor winding in the refrigerator fixed frequency compressor, and the frequency conversion refrigerator compressor usually adopts a frequency conversion compressor, and the compressor motor is a three-phase winding (identified by U, V, W), and the detection method is the same as the detection method of the fixed frequency compressor motor. However, the determination method of the measurement result is different, and there is a certain resistance value between the three-phase windings of the inverter compressor motor, and the resistance of the three groups is exactly the same.
4. Detect the insulation resistance of the compressor
The windings of the compressor motor should be insulated from the housing. If there is a short circuit between the motor winding and the housing, it may not only cause compressor failure, but also may cause machine leakage. Therefore, in addition to detecting the compressor by the above method, the compressor can also be judged by the method of detecting the insulation resistance of the compressor motor. For more information about detection methods, see the following illustration.
Clip the crocodile clips on the two test lines of the insulation resistance meter to the terminals and housings of the compressor windings. Shake the insulation resistance meter rocker clockwise, normally, the compressor motor winding and the housing should be in an insulated state, the resistance value should be 500MΩ.
Under normal circumstances, the resistance between the compressor motor windings and the compressor housing should be infinity (the insulation resistance table indicates 500MΩ). If the measured resistance is small, it means that there is a short circuit between the motor winding and the housing in the compressor, and the insulation should be restored or the compressor should be replaced directly.
If there is no insulation resistance meter in the actual test, you can also use the multimeter to detect the insulation resistance of the compressor and roughly determine whether the compressor motor windings and the housing are short circuited.