Sudden silence of the refrigerator or, conversely, its convulsive attempts to start with a characteristic click often indicate a problem in compressor electrical circuit. Owners of equipment from the Belarusian brand Atlant often encounter a situation where the engine hums for a couple of seconds, then a knock is heard, and the unit quiets down again. This is a classic symptom of failure of the starter mechanism, which is responsible for starting the engine and protecting it from overheating.
Independent diagnosis of this unit is a very real task for a home craftsman who has basic skills in working with tools. Understanding the principle of operation starting relay will allow you to save a significant amount on calling a technician and quickly return the refrigerator to operation. In this article, we will look in detail at how to identify a malfunction, what tools will be required and what to pay special attention to when replacing.
Before you begin disassembling, it is important to realize that you are dealing with an electrical device operating on a 220-volt network. Any manipulations inside the case are possible only after the device is completely disconnected from the power supply. You should not ignore safety rules, since even when turned off, some elements can retain a residual charge, although in the case of relays this is less critical than with capacitors.
Symptoms and signs of a malfunction of the starting relay
You can determine that the problem lies precisely in the starting mechanism by the characteristic behavior of the refrigeration unit. Most often, the malfunction manifests itself in a cyclic repetition of the same sequence of actions: the engine tries to start, emits a hum, a click is heard, and there is silence. After a few minutes or even seconds, the cycle repeats. This means that thermal protection triggered, turning off the compressor to prevent it from burning out.
Another clear sign is the absence of the characteristic sound of a running compressor when the refrigerator is turned on. If you only hear a low hum or complete silence but the light inside is on, the trigger circuit is most likely broken. In some cases, the breakdown is accompanied by the smell of burning or melted plastic in the area of the engine compartment, which indicates overheating of the contacts or windings.
⚠️ Attention: If you smell a persistent smell of burnt wiring or see traces of soot on the parts, do not try to turn on the refrigerator repeatedly. This can lead to complete failure of the compressor, the repair of which will cost much more than replacing the relay.
Sometimes a refrigerator can work, but at the same time become very hot in the compressor area or consume more electricity than usual. These are indirect signs that the starting mechanism is not working correctly, creating unnecessary resistance or not providing a full start of the engine rotor. In such cases, a timely check will help prevent more serious breakdowns.
The design and operating principle of the relay in Atlant refrigerators
To effectively check a part, you need to understand how it works. Refrigerators Atlant most often use electromagnetic starting relays, although in older models you can also find posistor options. The electromagnetic device works by passing current through a coil, which creates a magnetic field that draws in the core and closes the contacts.
When the refrigerator is turned on, the current passes through the working winding of the motor and the relay coil. Since the starting current is high, the magnetic field draws in the core, completing the starting winding circuit, which allows the rotor to spin. As soon as the engine picks up speed, the current drops, the core under the action (and the spring) drops, opening the starting circuit. In parallel with the starting one, it often operates thermal relay, which opens the circuit when overheated.
The difference between a posistor and electromagnetic relay
A posistor relay works based on the property of the material to change resistance when heated. When cold, it passes current to the starting winding, heats up and opens the circuit. Electromagnetic relies on the mechanical movement of a core under the influence of current. Visually, posistors often have a white or grayish ceramic body, and electromagnetic ones have a black plastic case with a visible coil inside.
It is important to note that in modern models Atlant the starting and thermal relays are often combined into one housing, which simplifies replacement, but requires care during diagnostics. Inside the housing there is a coil, a movable core, contacts made of silver or special alloys, as well as a bimetallic thermal release plate. Any sticking of contacts or loss of elasticity of the spring leads to malfunctions.
Necessary tools for diagnostics
To carry out high-quality diagnostics, you will need a minimum set of tools that most home craftsmen can find. The main device will be a multimeter (tester), which allows you to measure resistance and check the integrity of the circuit. Without this device, an accurate check is impossible, since a visual inspection does not always reveal internal breaks.
In addition to the multimeter, prepare the following tools:
- 🔧 A set of screwdrivers (flat and Phillips) for removing the back cover and dismantling the compressor casing.
- 🔨 Pliers or pliers for carefully removing terminals and fixing wires.
- 🧹 A soft brush or dry rag to clean the contacts from dust and oxides.
- 📱 A smartphone with a camera to take a picture of the connection diagram before disassembling.
Make sure that your multimeter is working properly and has working batteries. To test a relay, a resistance measurement limit of 200 Ohms or a continuity test is usually sufficient. If you plan to clean the contacts, you may need fine sandpaper or a needle file, but use them with extreme caution so as not to remove too much metal.
☑️ Preparing for diagnostics
Step-by-step instructions for removing the relay
The first step in the diagnostic process is to gain access to the compressor. Open the back panel of the refrigerator Atlantwhich is usually secured with latches or screws. Having removed the panel, you will see a black cylindrical or pear-shaped compressor, to the bottom of which a small plastic or metal box is attached - this is our desired device.
The dismantling process is as follows:
- Carefully inspect the fasteners. The relay is usually placed directly on the three contact pins of the compressor and can be additionally fixed with a metal bracket or a plastic clip.
- If there is a fixing bracket, carefully bend it with pliers or remove it by pressing on the special protrusions.
- Remove the relay from the compressor contacts. It may fit tightly, so wiggle it slightly from side to side, but do not apply excessive force to avoid damaging the terminals.
- Disconnect the wires going to the relay. Remember or take a photo of which wire is connected where. Usually there are two or three of them, and they come from the power cord and the thermostat.
After removing the device from the compressor housing, you can remove the protective plastic casing of the relay itself. In some models Atlant it is held on by latches, in others it needs to be carefully pryed off with a screwdriver. Inside you will see the coil, core and contacts. Visually assess the condition of the parts: there should be no traces of burning, melting or destruction.
⚠️ Attention: When removing the relay from the compressor, keep it strictly in the position in which it was installed (usually with the arrow pointing up). Turning the relay over can lead to the core falling out or malfunction of the mechanism, if it is still working.
Checking the relay with a multimeter: table of values and algorithm
The most accurate diagnostic method is to check the resistance with a multimeter. Switch the device to resistance measurement mode (Ohm). First check the integrity of the electromagnet coil. The probes are applied to the corresponding relay contacts. The resistance of a working coil is usually from 30 to 60 Ohms, depending on the model and power of the compressor.
Next you should check the thermal release. In a cold state, its resistance should be close to zero (continuity mode). If the multimeter shows infinity (one on the left side of the screen), then the circuit is broken and the relay must be replaced. It is also important to check the contacts: in the initial position they can be open or closed depending on the design, but when voltage is applied (under bench conditions) they must change state.
For ease of understanding, the main test parameters are summarized in the table:
| Check element | Normal reading | Symptom of malfunction | Action |
|---|---|---|---|
| Electromagnet coil | 30 - 60 Ohm | Infinity or 0 Ohm | Relay relay |
| Thermal protection | 0 - 1 Ohm (closed) | Infinity (open) | Relay replacement |
| Contacts (visual) | Clean, without carbon deposits | Black coating, melting | Cleaning or replacement |
| Movable core | Free movement | Sticking, rust | Cleaning or replacement |
If the coil rings, the thermal protection is intact, and the contacts are clean, but the refrigerator does not start, the problem may be in the compressor itself or in the supply wires. However, in 90% of cases with the described symptoms, it is the starting device that is to blame. The critical parameter is the coil resistance: if it deviates greatly from the norm (for example, 5 Ohms or 500 Ohms), the relay will not work.
Replacement and selection of analogues for the Atlant refrigerator
If the diagnostics showed a malfunction, the relay must be replaced. Repairing old devices by stripping contacts or bending springs is a temporary measure and often ineffective. New relays are inexpensive and provide reliable operation. When purchasing, it is important to pay attention to the markings that are applied to the body of the part.
For refrigerators Atlant relays of the following series are most often used:
- 🔹 RTK-X (for example, RTK-1, RTK-2, RTK-3) - suitable for many single-compressor models.
- 🔹 P-1, P-2, P-3 - common modifications for compressors of various capacities.
- 🔹 s (Danfoss) 101N0101 and analogues - often installed on more modern Atlant models.
When selecting an analogue, be guided not only by the name, but also by the compressor power indicated on the nameplate (for example, 1/5 hp, 1/4 hp). The number of pins (usually 3) and their location are also important. If you do not find an original spare part, you can use universal relays, but make sure that the current characteristics match.
The process of installing a new relay is simple: put it on the compressor pins until it stops, observing the orientation (the "UP" or "UP" arrow should face up). Then connect the wires to the relay contacts according to the photo you took earlier. Install the retaining bracket and protective cover. After assembly, turn on the refrigerator and listen: the start-up should be quiet and confident, without unnecessary clicks.
What happens if you mix up the wires when connecting the relay?
If you mix up the wires going to the starting and working windings, or connect the phase and zero incorrectly, the compressor may not start, hum or start in the opposite direction (which is for piston compressors critical and leads to valve failure). In the best case, the thermal protection will work, in the worst case, the motor winding will burn out. Always take a photo before disassembling.
Is it possible to start a refrigerator without a relay?
Theoretically, you can start the compressor by applying voltage directly to the starting winding for a short time, but this is extremely dangerous and requires the skills of an electrician. For domestic use, this method is not recommended, since there is a high risk of getting an electric shock or damaging the compressor due to the lack of thermal protection.
Why does a new relay burn out after a week?
If a new relay fails quickly, the reasons may be the following: an incorrectly selected model (wrong current), poor contact in the terminal block, power surges in the network, or, worse, In general, there is a malfunction of the compressor itself (interturn short circuit), which consumes too much current.