A sudden stop of the refrigerator is always a stressful situation for the owner, since the food supplies. If you notice that your Atlant refrigerator has stopped freezing, but the light is on inside, and the unit itself makes characteristic clicks or a humming noise that ends abruptly, this is a sure sign of problems with the motor. The first and most accessible method of diagnostics at home is to check the integrity of the electric motor windings, or, in simple terms, a “continuity test.”
Many service center technicians begin with this stage, since it allows you to exclude or confirm the most serious breakdowns without disassembling the entire system. However, it is worth understanding that the compressor is the heart of the refrigerator, and its serviceability depends not only on the condition of the coils, but also on related elements, such as the start relay and thermal relay. In this article, we will analyze the diagnostic process in detail so that you can independently determine whether your device needs to replace an expensive component or the problem can be solved cheaper.
Before taking active steps, you need to ensure safety. Any work related to electrical components requires completely disconnecting the device from the network. Even if the refrigerator is not operating, voltage may be present in the circuit and careless movement may result in electric shock. Therefore, the first step should always be to remove the plug from the socket and prepare a workplace with good lighting.
Preparation for diagnostics and necessary tools
To properly check the compressor, you will need a minimum set of tools that most home craftsmen can find. The main device will be a multimeter (tester) capable of measuring resistance in Ohms. Without this device, it is almost impossible to carry out accurate diagnostics, since it is impossible to determine the condition of the windings “by eye”. A set of screwdrivers is also useful for removing the rear protective panel and accessing the motor.
It is important to check the condition of the wires and contacts visually before starting measurements. Often the cause of the malfunction lies not in the engine itself, but in oxidized contacts or a burnt start relay. If you see traces of burning, melted plastic or smell burnt insulation, this may indicate a short circuit, which led to the failure of the entire system.
⚠️ Attention: Before starting any work, make sure that the capacitors in the circuit are discharged, although they are rare in Atlant household refrigerators. Never touch the metal parts of the multimeter probes during measurements, as this will distort the readings of the device.
Prepare a clean rag for wiping the contacts. Dirt and oil can create additional leakage currents, resulting in incorrect resistance readings. If the compressor is old and heavily dirty, it makes sense to carefully wipe the area around the terminals to ensure reliable contact of the tester probes with the terminals.
☑️ Diagnostic tools
Access to the compressor and removal of the protective cover
B brand refrigerators Atlant the compressor is traditionally located in the lower rear part of the case. To access it, you need to move the unit away from the wall, providing free access from behind. Be careful not to damage the copper tubes coming from the motor, as they are very thin and easily deformed.
On the back wall you will see a metal or plastic panel covering the compressor compartment. It is usually secured with four bolts or latches. Use a suitable screwdriver to remove this guard. After removing the panel, you will have a view of the black cylindrical tank - this is the compressor, to the bottom of which is attached a casing with a starting relay.
The next step is to remove the casing itself (crankcase), which contains the starting and thermal relay. It is usually secured with a metal clamp or spring clip. Carefully release the latch and remove the plastic box, freeing access to the compressor contact group. It is here that there are three pins that we have to call.
Connection diagram and identification of terminals
The contact group of the Atlant refrigerator compressor usually has three terminals arranged in a triangle. For proper diagnosis, it is critical to understand which pin does what. On most models, these contacts are marked with Latin letters or numbers, but over time the markings may fade or become unreadable due to carbon deposits.
The standard marking is as follows:
- 🔵 R (Run) — working winding, the main wire for starting the engine.
- 🟢 S (Start) — starting winding, responsible for creating the initial torque.
- ⚫ C (Common) —the common wire to which power is supplied.
Sometimes instead of letters there may be numbers, for example, 1, 2, 3, but the logic remains the same: one common contact and two phase ones.
If there is no marking, you can determine the conclusions by the method of exclusion during dialing, which we will talk about in the next section. Therefore, if you are in doubt about the identification of contacts, it is better to check the technical documentation or electrical diagram, which is often pasted on the inside of the removed protective panel.
| Designation | Purpose | Wire color (usually) | Resistance |
|---|---|---|---|
| C (Common) | Common contact | Red or black | Sum of R and S |
| R (Run) | Working winding | Green or blue | Average |
| S (Start) | Start winding | Yellow or white | Highest |
| Case | Grounding | Green with a stripe | Infinity |
Why do the windings have different resistance?
The starting winding is wound with a thinner wire and has more turns, so its resistance is always higher than that of the working winding. The working winding is designed for direct current and is made with a wire of a larger cross-section.
The process of testing the windings with a multimeter
Now we move on to the most important thing - measurements. Switch the multimeter to resistance (Ohm) measurement mode, selecting a limit of 2 kOhm or 20 kOhm. First you need to connect the probes to each other to make sure that the device shows zero and is working properly. If the unit or infinity symbol is lit on the screen, it means the circuit is broken.
The check should be carried out in pairs between all three contacts. First apply the probes to pins C and R, then to C and S, and finally to R and S. Record the readings. Normal resistance values for Atlant compressors vary within the following limits: operating winding - from 10 to 35 Ohms, starting winding - from 20 to 60 Ohms. The sum of the resistances of the two windings should be approximately equal to the resistance between the extreme contacts.
The most important step is checking for breakdown on the housing. To do this, press one multimeter probe to any of the three contacts, and the second one to the cleaned metal part of the compressor housing (you can slightly scratch the paint for better contact). If the device shows at least some resistance value (the arrow deviates or the numbers change), it means that the insulation of the windings is broken and the motor is faulty.
⚠️ Attention: If the multimeter shows a resistance close to zero between any two contacts, this indicates an interturn short circuit. Such a compressor will not work and requires replacement, since rewinding at home is not economically feasible.
During the measurement process, pay attention to the stability of the readings. The numbers should not "jump". If the resistance slowly increases, the contacts of the probes or the compressor leads themselves may have oxidized. In this case, clean the contacts with fine sandpaper and repeat the procedure.
Analysis of results and typical faults
After receiving all the data, it is necessary to interpret it correctly. If all three measurements between the contacts show resistance within acceptable limits, and a test on the housing gives infinity, then the electrical part of the compressor is working. This is great news, since the problem most likely lies in the start relay or thermostat.
However, if you find an open circuit (infinite resistance) between the contacts, this indicates a burnt out winding. Often it is the starting winding that burns out due to jamming of the piston group or power surges in the network. In this case, the compressor hums, but cannot start, and after a few seconds the thermal protection is triggered.
The most dangerous option is an interturn short circuit. In this case, the winding resistance will be significantly lower than normal. The engine may even start, but it will overheat, make a loud noise and quickly turn off the thermal relay. It is impossible to operate a refrigerator with such a malfunction, as this can lead to a fire.
Diagnostics of the start relay and additional checks
If the continuity test of the compressor itself does not reveal any problems, but the refrigerator does not turn on, you need to check the start relay. Atlant refrigerators often use RT or R-3 series relays. Remove the relay from the housing and inspect it for external damage. Inside there is a coil and contacts that can burn out over time.
Ring the relay coil. The resistance of a working coil is usually several tens of ohms. If the device shows an open circuit, the relay is faulty. Also check the thermal release - it should “ring” (show zero) when cold. If the thermal release is open, you can carefully heat it with a hair dryer (not an open fire!) to 70-80 degrees, and it should click, restoring the circuit.
Sometimes the cause of the failure is not the motor itself, but insufficient voltage in the network or a malfunction of the thermostat. If the compressor is working but does not start, try applying power directly for a short time (literally 2-3 seconds), bypassing the relay, but this should only be done by experienced users who understand the risks. A safer method is to replace the relay with a known good one.
In conclusion, it is worth noting that the technical condition of the compressor may depend on operating conditions. If the refrigerator stood for a long time in an unheated room at subzero temperatures, the oil in the compressor could thicken, which would make the first start difficult. In such cases, it is necessary to keep the unit warm for 24 hours.
Is it possible to restore a burnt-out compressor?
Restoring a burnt-out compressor at home is impossible. Rewinding windings requires special equipment and technology, and the cost of such work will exceed the price of a new compressor. If the windings are burned out, the unit must only be replaced.
Why does the compressor hum but does not start?
This is a classic sign of a jammed piston group or a faulty start relay. The motor tries to turn over, but a mechanical obstacle or the lack of a starting impulse does not allow it to gain momentum, and the thermal protection is triggered.
Which multimeter is better to choose for diagnostics?
Any entry-level digital multimeter (for example, DT-830 or its analogues) is suitable for household needs. The main thing is that it correctly measures resistance and has a sound continuity of the circuit.