A sudden stop of the compressor or its refusal to start often puts refrigerator owners Atlant into a dead end. In most cases, the culprit of the malfunction is the start-up relay, which is responsible for starting the engine and protecting it from overloads. Understanding exactly how this unit functions will allow you to independently diagnose the problem and avoid an expensive call to a technician.
The relay in refrigerators Atlant performs a dual function: it supplies a pulse to the starting winding to start the rotor and opens the circuit when operating speed is reached, and also turns off power when overheating or power surges occur. This compact device is a critical element of the electrical circuit, without which normal operation of the compressor is impossible.
In this article we will examine in detail the internal structure of various types of relays used in Belarusian-made household appliances. You will learn how induction mechanisms differ from posistor mechanisms, and learn to identify signs of their failure by external symptoms and sound signals.
The principle of operation of the starting protection mechanism
The main task of the relay is to briefly connect the starting winding of the electric motor. When the refrigerator is turned on, the compressor rotor is stationary, and moving it from its place requires a significant force, which is created by the starting winding. As soon as the engine reaches the required speed, the relay automatically turns off this winding, leaving only the main winding to work.
In parallel with the starting function, the device acts as a thermal fuse. Inside the housing there is a bimetallic plate that reacts to the strength of the current passing through the windings. Thermal relay opens the contacts if the current exceeds permissible limits, preventing engine combustion when jammed or power surges in the network.
It is important to note that in Different models Atlant can use different circuit breaking principles. In older series, induction relays were often found, where the opening occurred due to a drop in current in the main winding after the rotor had spun up. Modern models are often equipped with posistor elements that operate on the principle of changing resistance when heated.
Types of relays used in Atlant refrigerators
The range of relays for equipment Atlant is quite wide, and the choice of a specific model depends on the year of manufacture of the refrigerator and the type of compressor installed. The main division occurs into induction (mechanical) and posistor (electronic) devices, each of which has its own design features.
Induction relays, such as the RTP or RSO series, operate thanks to an electromagnetic coil. When voltage is applied, current passes through the coil, creating a magnetic field that draws in the core and closes the contacts of the starting winding. After the engine starts, the current drops, the core drops under the influence of gravity, and the circuit opens. These models are durable, but sensitive to the position of the housing.
- 🔧 RTP-1 is a classic induction relay installed on single-compressor models with a vertical shaft arrangement.
- 🔧 RSO-PZ is a combined device, where the starting part is inductive, and the protective part is based on a bimetallic plate.
- 🔧 PTC (Posistor) —a solid-state element that has no moving parts, working by heating the crystal with current.
Posistor relays, or PTC startersrepresent is a tablet made of a special material, the resistance of which increases sharply when heated. When the refrigerator is turned on, the posistor is cold and passes current to the starting winding. The current heats the element, its resistance increases, and the current is almost completely blocked. Such relays are cheaper and more reliable in vibration conditions, but require time to cool down before restarting.
Diagnostics of relay malfunctions
You can determine that the refrigerator relay Atlant has failed by the characteristic signs that appear immediately after turning on the device in the network. Most often, the user hears a click, followed by the hum of the compressor, lasting several seconds, after which a second click is heard and silence ensues.
Such a cycle can be repeated periodically until the refrigerator is de-energized. This indicates that the starting pulse is not reaching the motor, or the protective mechanism is triggered instantly due to a short circuit inside the relay itself. In some cases, the relay may “stick”, leaving the starting winding on, which leads to rapid overheating and humming of the motor.
⚠️ Attention: If after clicking the relay the compressor hums but does not start, do not keep the refrigerator on for more than 10-15 seconds. This can cause the motor windings to burn out.
Visual inspection can also provide important clues. If traces of soot, melted plastic, or a burning smell are visible on the relay body, then the device definitely requires replacement. It is also worth checking the contacts for oxidation, which often occurs due to moisture or condensation entering the compressor niche.
Checking the relay with a multimeter
For accurate diagnostics, you need to remove the relay from the compressor and ring its contacts with a multimeter. Before starting work, be sure to disconnect the refrigerator from the power supply. Remove the back cover at the bottom of the unit and disconnect the wires leading to the starter protection device.
Checking the induction relay is carried out in an inverted state (marked up). In this position, the contacts of the starting winding must be closed. The multimeter in dial mode should show zero or close to it resistance between the corresponding contacts. If you turn the relay over with the marking down, the circuit should open and the device should be silent.
To check the posistor, you need to measure its resistance in a cold state. It should be several tens of ohms (usually from 10 to 60 ohms, depending on the model). If the device shows infinity (open) or zero (short circuit), the posistor is faulty. It is also important to check the thermal relay: in a cold state, its contacts must be closed.
Procedure for checking:1. Turn off the power to the refrigerator.
2. Remove the relay from the compressor contacts.
3. Set the multimeter to resistance measurement mode (200 Ohm).
4. Ring the circuit between contacts 1-3 (starting) and 1-2 (main).
Pay special attention to the condition of the bimetallic plate. It should not have visible deformations or signs of overheating. If, when heated (for example, by a hairdryer), the contacts of the thermal relay do not open, it means that the protection will not work at a critical moment, which is dangerous for the compressor.
☑️ Checking the relay with a multimeter
Replacement instructions relay
Replacing the relay in the refrigerator Atlant is a procedure that is accessible even to a beginner, if you are careful and follow the sequence of actions. The main rule: all work is carried out only on completely de-energized equipment. The new part must fully correspond to the markings of the old one, especially in terms of starting current parameters.
First remove the old relay. It can be mounted on the compressor frame or simply put on the contacts. Gently pull it down or to the side, releasing the contact group. Pay attention to the wiring diagram: it is best to photograph the location of the terminals before disconnecting, so as not to confuse them when installing a new element.
| Relay type | Contact markings | Installation features | Compatibility |
|---|---|---|---|
| RTP-1 | 1, 2, 3, 4, 5 | Vertical only | Old Atlant models |
| RSO-PZ | 1, 2, 3, 4 | Vertical/Horizontal | Universal |
| PTC (China) | No marking | Any position | Modern models |
| DR-2 | 1, 2, 3 | Vertical | Low-power compressors |
Install the new relay on the contact group of the compressor until there is a characteristic click or a tight fit. Make sure that the device is secured in the frame or holder so that vibration during operation does not disrupt contact. Connect the wires according to the previously made diagram or photograph.
⚠️ Attention: Incorrect orientation of the induction relay (upside down) will lead to the fact that the starting winding will not turn off, and the compressor will burn out after a few minutes of operation.
What to do if the new relay does not fit the mounts?
In some cases, new relays may have slightly different housing geometry. If the contacts match in pattern and distance, you can carefully trim the plastic guide frames or use heat-resistant sealant for fixation, but only if this does not interfere with the vibration of the compressor.
Common mistakes during repairs
When repairing refrigerators on their own Atlant amateur craftsmen often make mistakes that can lead to repeated failure. One of the most common is ignoring the reason for the failure of the old relay. If the relay burns out due to problems with the compressor (turn-to-turn short circuit), then replacing the relay itself will not solve the problem for a long time.
Another mistake is using a relay with an inappropriate starting current. Installing a device with a lower current will cause the relay to constantly fire, preventing the compressor from starting. Too much current reserve can lead to the fact that the relay does not break the starting winding circuit in time.
They also often forget about the cleanliness of the contacts. When installing a new relay, you must make sure that the contacts on the compressor itself are not oxidized or burnt. If the compressor pins have a black coating, they should be carefully cleaned with fine sandpaper or a file before putting on a new device.
FAQ: Frequently asked questions
Is it possible to start an Atlant refrigerator without a relay?
Theoretically, you can start a compressor without a relay by manually applying voltage to the starting winding, but this is extremely dangerous and is not intended for constant operation. Without a thermal relay, the engine will burn out at the first overload, and without a starting mechanism it simply will not gain momentum. Operating a refrigerator without a standard relay is prohibited.
Why does the relay click, but the refrigerator does not freeze?
Clicks indicate an attempt to start. If the compressor hums and clicks, but does not start, the compressor itself may be jammed (water hammer, worn-out pairs), the relay is faulty (does not give a starting impulse), or there is a problem in the wiring. Diagnostics with a multimeter is required.
How often do you need to change the relay in the refrigerator?
A relay is a resource part, but during normal operation it lasts for years, often as long as the compressor itself. Frequent replacements (once a year or more often) indicate unstable voltage in the network or incipient problems with the refrigerator motor.
Is it possible to use a universal relay for Atlant?
Yes, there are universal relay kits that are suitable for many models of refrigerators. The main thing is that the rated starting current of the universal relay meets the requirements of your compressor Atlant. Usually the current range is indicated on the case.