When household appliances stop cooling or makes unusually loud sounds, the first thing the owner does is wonder about the nature of this “heart” of the unit. Many people call this unit simply a motor, by analogy with washing machines or cars, but the technically correct name is compressor. It is responsible for circulating the refrigerant through the system, creating the necessary pressure to effectively remove heat from the chambers.
Understanding how this mechanism is correctly named and functions is critical for diagnosing malfunctions. Unlike a simple electric motor, refrigeration compressor is a complex unit that combines electrical and mechanical parts in a sealed housing. Different manufacturers can use different technologies, from classic piston to modern inverter systems, and each of them has its own operating characteristics.
In this article we will analyze in detail why the engine is called a compressor, how different types of units differ and what to look for at the first signs of unstable operation. You will learn how to determine the type of unit installed in your refrigerator and whether it is worth trying to repair it yourself or is it better to turn to professionals.
Technical nomenclature: why the engine is called a compressor
The term “engine” in the context of refrigeration equipment is rather a household simplification. Technically, there is indeed an electric motor inside the sealed casing, but its only job is to rotate the shaft of the mechanical part that compresses the gas. Therefore, the correct term for the entire assembly is compressor. It converts electrical energy into the energy of compressed refrigerant vapor, causing it to move along the circuit.
It is important to distinguish between these concepts when you are looking for spare parts or reading technical documentation. If you search for a “motor for a refrigerator,” you may come across system fans No Frostwhich are also motors, but perform a completely different function. There is always one compressor (in standard models) and it is located, as a rule, in the lower rear part of the housing.
⚠️ Attention: When ordering spare parts, never use the word “engine”. Indicate the exact model of the compressor or the article number indicated on the nameplate, since visually similar units may have different power, type of refrigerant and mounting method.
There is a common misconception that all compressors work the same. In fact, the compression principle can be radically different. Classic models use a reciprocating piston motion, while more modern and quieter versions may work on the principle of rotating spirals or even have no moving mechanical parts in the traditional sense, like linear models. Understanding this difference will help you choose a quieter and more economical appliance when purchasing a new device.
Design features and principle of operation
The internal structure of the compressor is a sealed metal cylinder, inside which the main working elements float in an oil bath. This design is called sealed unit. Oil is necessary to lubricate rubbing parts and remove heat. The electric motor and mechanical part (crank mechanism or spiral mechanism) are mounted on springs to dampen vibrations during operation.
The principle of operation is based on changes in refrigerant pressure. Low-pressure freon gas is sucked through the suction tube, compressed in the chamber and, at high pressure and temperature, released into the discharge tube, entering the condenser (radiator at the back of the refrigerator). This cycle is repeated constantly, maintaining the set temperature temperature in the chambers.
The key elements of the internal design are:
- 🔩 Electric motor - creates a rotational movement, hidden inside the casing.
- 🔩 Piston group - directly compresses the gas (in piston models).
- 🔩 Valve mechanism - regulates the direction of refrigerant flow, preventing reverse flow.
- 🔩 Starting and thermal relay —are located outside the casing, responsible for starting and protecting against overheating.
It is worth noting that modern models are often equipped with additional cooling systems for the compressor itself, since overheating is the main cause of failure. The temperature of the casing during normal operation can reach 70-90 degrees Celsius, which is normal, but requires effective heat dissipation.
Why is the compressor sealed?
Sealing is necessary to prevent leaks of freon, which is under pressure, and to protect internal mechanisms from moisture and dust. It is impossible to open it at home - the casing is either sawed or cut, and after repair it is welded again or bolted to seals, which requires special equipment and skills.
Types of compressors: from classics to inverters
There are several main types of compressors on the household appliances market, and each of them has its own advantages and disadvantages. The most common and time-tested is piston compressor. It works on the principle of a car engine: a piston moves up and down, compressing gas. Such units are reliable, maintainable, but can be noisy and consume electricity due to constant on and off cycles.
A more modern alternative is inverter compressor. Its main difference is the ability to smoothly regulate the engine speed, and not work in start-stop mode. This allows you to maintain the temperature with high accuracy, reduce noise levels and save up to 40% of energy. However, such systems are sensitive to voltage drops in the network and are more difficult to repair.
It is worth highlighting separately linear compressors, which are often used by LG. They do not have a crank mechanism; the piston moves in a straight line due to electromagnetic forces. This reduces the number of rubbing parts, making the unit very quiet and durable. However, the cost of replacing such a unit is usually higher than that of classical analogues.
| Compressor type | Noise level | Economy | Maintainability |
|---|---|---|---|
| Piston | Medium/High | Standard | High |
| Inverter | Low | High | Medium |
| Linear | Very Low | High | Low |
| Rotary | Low | Medium | Low |
⚠️ Attention: Inverter and linear compressors often require the use of original control boards. When replacing the compressor itself, it may be necessary to reflash or replace the refrigerator electronics, which increases the cost of repairs.
Fault diagnosis: how to understand that the engine is "dying"
You can determine the impending failure (impending failure) of the compressor by a number of characteristic signs. The most obvious is that the refrigerator has stopped freezing, but the light inside is on. If you hear that the compressor is hummingbut does not start, or starts for a couple of seconds and stalls with a click, this is a sure sign of a problem with the starting mechanism or motor windings.
Another alarming symptom is continuous operation without shutting down. If the refrigerator hums for days on end without turning off, this may indicate a loss of compressor performance (wear of the piston group) or a freon leak. In the latter case, the engine tries to compensate for the lack of refrigerant by constant operation, which leads to its overheating and eventual burnout.
Pay attention to the following signs:
- 🔊 Knocking and clanging - indicate broken bearings or damage to the engine mount inside the casing.
- 🔥 Extreme heating - if the casing is red hot or there is a burning smell coming from it, immediately turn off the device.
- 💡 Flashing light —when starting an old compressor, the light in the apartment may dim due to the high starting current.
For more accurate diagnostics, specialists use a multimeter to check the resistance of the windings and a pressure gauge station to check the discharge pressure. However, an initial assessment of the condition can be carried out visually, paying attention to the nature of the operation and sounds of the unit.
☑️ Symptoms of compressor failure
Replacement and repair: is it worth the candle
Repairing a compressor at home almost impossible due to the need to open the sealed housing and the presence of a special tool for charging the refrigerant. Usually a full replacing the unitis produced. This process includes unsoldering old tubes, dismantling the old unit, installing a new one, evacuation of the system and charging with freon.
The cost of such repairs is often 50-70% of the price of a new refrigerator, especially when it comes to models with inverter or linear compressors. Therefore, if your refrigerator is more than 10 years old, it is often more economically feasible to purchase new equipment than to invest in a major overhaul of the old “heart.”
A critically important point when replacing is the selection of a compressor with identical cooling capacity and type of refrigerant. Installing a more powerful or less powerful unit will either lead to undercooling or rapid wear of the new part and freezing of products.
Operation rules for extending service life
In order to refrigerator motor last the period declared by the manufacturer (usually 10-15 years), you must follow a number of simple rules. First, ensure adequate ventilation in the installation area. The gap between the back of the refrigerator and the wall should be at least 5-7 cm so that the heat from the condenser and compressor is effectively dissipated.
Secondly, avoid frequent switching on and off. If you turn off the refrigerator, it is recommended to turn it on again no earlier than after 5-10 minutes. This time is necessary to equalize the pressure in the system and cool down the starting relay. An instant restart can lead to water hammer in the compressor or burnout of the windings.
Also keep the rear panel clean. Dust, animal hair and cobwebs adhering to the condenser grille and the compressor itself act as a heat insulator, causing the unit to work under overload. Regular dry cleaning of this area is an easy way to extend the life of the equipment.
Is it possible to replace a conventional compressor with an inverter one?
Theoretically it is possible, but in practice it is extremely difficult and expensive. It will require replacing the entire control system (board), resoldering the tubes and complex setup. This is not economically feasible - it is cheaper to buy a new refrigerator with an inverter.
Why does the compressor vibrate strongly?
Vibration can be caused by loosening of the fastening bolts, wear of the rubber shock absorbers on which the motor is suspended inside the casing, or contact of the tubes with the body of the refrigerator. Sometimes this is a sign of internal destruction of the mechanism.
How much does it cost to replace a compressor?
The price consists of the cost of the unit itself (from 3 to 15 thousand rubles) and the work of a specialist with materials (freon, solder, filter). On average, replacement costs 6-12 thousand rubles, depending on the model of the refrigerator.
The humming has stopped, the refrigerator is silent - is this good?
If the refrigerator is silent and does not freeze, this is bad. If it is silent, but it is cold inside, the thermal protection relay may have tripped due to overheating, or the starting relay may be faulty. Diagnostics is required.
Can the compressor operate without freon?
For a short time - yes, but it cannot run idle for a long time. The lack of refrigerant leads to a lack of cooling of the motor windings, which causes rapid overheating and combustion of the insulation.