Imagine opening the refrigerator door after a long day at work, expecting to see fresh food and coolness, but instead you are greeted by warm air and silence, broken only by the roar of the city outside the window. At this moment, few people think about the complex physical processes that had to occur inside the metal box, maintaining a low temperature. The heart of this system, its main engine, is compressor, without which the operation of the entire unit becomes physically impossible.
It is this unit that is responsible for circulating the refrigerant through the system, causing it to give off heat to the outside and cool the internal chamber. Understanding what is a compressor in a refrigeratorwill help you not only choose household appliances wisely, but also notice the first signs of breakdown in time, avoiding spoilage of a large stock of products. In this article we will analyze in detail the structure of this mechanism, the types of motors and the nuances of their operation.
Many users perceive a refrigerator as a black box that simply needs to freeze, but the internal structure of modern equipment requires careful attention. Knowledge of the basic principles of operation compression unit will allow you to properly care for the device and extend its life for many years.
The basic principle of operation of the compressor
The fundamental task of the compressor is to create a pressure difference in the cooling system, which makes the refrigerant moves in a closed circuit. This process is reminiscent of the work of the human heart, which pumps blood through the vessels, only here instead of blood, freon or other gaseous refrigerant circulates. The motor compresses the gas, increasing its pressure and temperature, after which the hot gas enters a condenser, usually located on the rear wall, where it cools and turns into liquid.
After passing through a filter drier and a capillary tube, where the pressure drops sharply, the refrigerant enters the evaporator inside the chamber. Here the reverse process occurs: the liquid boils at a low temperature, actively absorbing heat from the refrigerator compartment. The vapors are then sucked back into the compressor and the cycle repeats. Without this continuous movement working fluid heat exchange would be impossible, and the temperature inside would be equal to room temperature.
It is important to understand that the compressor does not operate constantly, but cyclically, turning on and off according to a signal from a thermostat or an electronic control module. Modern models strive to minimize the number of starts, since it is at the moment of start that the greatest wear of mechanical parts occurs and the maximum current is consumed. Inverter technologies allowed to change this approach, making the operation of the motor smoother and more energy efficient.
⚠️ Attention: If you hear that the motor is humming, but does not start, or starts and immediately stalls - immediately disconnect the device from the network. Repeated attempts to turn on may lead to burnout of the electric motor windings or jamming of the mechanism.
The efficiency of the entire system directly depends on the performance of the supercharger. If the power is incorrectly selected or there is a freon leak in the system, the compressor will work with overload, trying to reach the set temperature. This leads to overheating of the housing and accelerated wear of parts.
Types of compressors: linear, inverter and piston
There are several main types of compressors on the household appliances market, each of which has its own design features and advantages. The most common and time-tested mechanism is piston a mechanism where gas compression occurs due to the reciprocating movements of the piston inside the cylinder. Such units are reliable, maintainable, but can be quite noisy due to vibration of moving parts.
A more modern solution is linear compressor, in which there is no crank mechanism. The movement of the piston here is carried out due to electromagnetic forces, which makes the operation of the device quieter and more economical. However, linear models are often criticized for the difficulty of finding spare parts and sensitivity to voltage changes in the electrical network.
Models are currently considered the pinnacle of evolution. Unlike traditional ones, they do not turn off completely, but only reduce engine speed, maintaining the temperature within specified limits. This avoids peak loads at start-up and significantly reduces noise levels. The inverter motor operates almost silently, which is especially important for studio apartments or open kitchens. inverter models. Unlike traditional ones, they do not turn off completely, but only reduce engine speed, maintaining the temperature within specified limits. This avoids peak loads at start-up and significantly reduces noise levels. The inverter motor operates almost silently, which is especially important for studio apartments or open kitchens.
The choice between these types often comes down to a balance between price and comfort. If the budget is limited, a classic piston unit will cope with its task no worse than expensive analogues, but will work louder.
It is also worth noting rotary compressors, which are more often found in industrial installations or very compact refrigerators. In them, compression occurs due to the rotation of the rotor in the cylinder. They are compact and effective, but their repair at home is almost impossible due to the high tightness of the case.
Device and internal components
Externally, the compressor is a sealed black metal tank, usually located in the lower rear part of the refrigerator. Inside this housing there is the electric motor itself and the mechanical part, immersed in a special oil, which provides lubrication of the rubbing parts. Sealed housing necessary to prevent refrigerant leakage and moisture entering the system.
The main internal elements include:
- 🔧 Electric motor — creates a rotational movement that is transmitted to the compressor shaft.
- 🔧 Piston group —directly compresses the gaseous refrigerant, creating high pressure.
- 🔧 Valve mechanism —regulates the direction of gas movement, preventing it from returning back to the evaporator.
- 🔧 Start relay —ensures the engine starts and protects it from overloads by opening the circuit when the permissible current is exceeded.
The oil inside plays a critical role. It must retain its properties over a wide range of temperatures and not freeze at low temperatures. Modern models use synthetic oils that have excellent fluidity and lubricity. If the oil loses its properties or its level drops, the rubbing parts will begin to wear out quickly, which will lead to jamming.
Also an important element is discharge tubethrough which the compressed gas exits the compressor. It is always hot, as gas heated during compression passes through it. It is by the temperature of this tube that the operation of the system is often diagnosed: if it is cold when the engine is running, it means that the compressor is not creating pressure (there is no compression).
⚠️ Attention: It is strictly forbidden to open the sealed compressor casing at home. There may be gas under pressure inside, and moisture or dust getting inside the mechanism will instantly disable it.
The compressor is attached to the refrigerator frame through special shock absorbers or rubber washers. They are necessary to dampen the vibration that inevitably occurs during operation of the piston mechanism. If these elements are worn out or lost during a previous repair, the refrigerator will vibrate and rattle heavily.
Comparing the characteristics of different types of motors
To better understand the differences between types of compressors and make an informed choice when purchasing or repairing, it is necessary to consider their key characteristics. Below is a table comparing the main parameters of popular types of units.
| Characteristics | Piston (Normal) | Linear | Inverter |
|---|---|---|---|
| Level noise | Medium / High | Low | Very low |
| Energy consumption | Standard | Economical | Maximum economical |
| Wear at start | High (frequent starts) | Medium | Minimum (soft start) |
| Repair cost | Low | High | High |
| Service life | 7-10 years | 10-15 years | 10-20 years |
As can be seen from the table, inverter models win in most respects, especially in terms of durability and energy efficiency. However, their high initial cost and the high cost of spare parts in the event of a breakdown may be a deciding factor against them for some users. A conventional piston compressor remains a “workhorse” that is easy and inexpensive to replace.
Linear compressors occupy an intermediate niche. They are quieter than regular ones, but inferior to inverter ones in smooth operation. Often such motors can be found in refrigerators in the middle price segment, where the manufacturer strives to offer a balance between price and comfort.
It is worth considering that the declared service life is a theoretical indicator, depending on operating conditions. Overheating, power surges and incorrect installation can shorten the life of even the most expensive inverter motor inverter motor
Signs of malfunction and diagnostics
Determine what refrigerator compressor works incorrectly, based on a number of external signs. The most obvious of them is a change in temperature. If the food in the chamber begins to deteriorate faster than usual or, conversely, freeze, this is the first signal of problems in the refrigerant circulation system.
The second important sign is a change in the nature of the motor. If it starts to turn on too often (short operating cycle) or, conversely, works without interruption, trying to gain temperature, this indicates a loss of performance or a freon leak. The appearance of extraneous sounds should also alert you: knocking, grinding or loud humming, which was not there before.
For more accurate diagnostics, you can use the following methods:
- 🔍 Tactile method — with the compressor running, one tube (discharge) should be hot, and the other (suction) should be cold. If both tubes are at the same temperature, there is no compression.
- 🔍 Visual inspection - check for traces of oil, swelling or melted wiring on the motor housing. The presence of oil indicates depressurization.
- 🔍 Current measurement —using current clamps, you can measure the current consumption. If it is significantly higher than the nominal value indicated on the nameplate, it means that the engine is overloaded.
A frequent problem is the failure of the starting relay. In this case, the compressor may hum for a couple of seconds, click and turn off without starting. This is a protective reaction of the system to the impossibility of starting the rotor.
Why is the compressor hot?
The normal operating temperature of the compressor housing can reach 90-110 degrees Celsius. This is necessary to evaporate moisture and oil that has entered the system. However, if the body is red-hot or there is a burning smell coming from it, this is a sign of a serious malfunction.
If you notice that the refrigerator has stopped freezing, but the motor is silent, do not rush to blame the compressor. Perhaps the problem is in the thermostat, which simply does not give the command to turn on, or in the absence of voltage in the socket.
Operating rules and extending service life
In order to compressor serve for as long as possible and do not require expensive repairs, you must follow a number of simple but important operating rules. First of all, this concerns the installation of a refrigerator. The unit must stand on a flat surface so that the oil is evenly distributed throughout the lubrication system and vibration is minimal.
It is critically important to maintain the temperature gap. The distance from the back wall of the refrigerator to the wall of the room should be at least 5-10 cm. This is necessary for free air circulation and effective heat removal from the condenser. If the refrigerator is placed close to the wall, the compressor will overheat, working hard.
You should also avoid frequently opening the door and placing hot foods inside. A sharp increase in temperature inside the chamber forces the compressor to work harder to restore the cold. This leads to an increase in the number of on and off cycles, which reduces the service life of the mechanism.
☑️ Checking operating conditions
Regular defrosting (for models with manual defrosting) also helps the compressor. A thick layer of ice on the evaporator acts as a heat insulator, preventing effective heat transfer. As a result, the motor is forced to work longer to cool the chamber.
⚠️ Attention: Never wash the refrigerator or wipe it with a damp cloth while it is plugged in. If water gets on the electrical contacts of the compressor or start relay, it can cause a short circuit and electric shock.
If you plan to be away for a long time, it is best to defrost the refrigerator, wash it and leave the doors ajar. This will prevent the appearance of mold and unpleasant odors, and will also give rest to mechanical components.
Repair or replacement: what to choose?
When the compressor fails, the owner is faced with the question: repair or replace? In the case of hermetic household compressors, a full-fledged repair (opening the housing, replacing valves, rewinding the motor) at home is impossible and economically impractical. Usually, the unit is completely replaced with a new or refurbished one.
Replacing a compressor is a complex technical procedure that requires special equipment: a vacuum pump, a pressure gauge station, a burner and a supply of refrigerant. The technician needs to unsolder the old motor, weld in a new one, replace the filter drier, evacuate the system and fill it with freon in a strictly defined amount.
The cost of such work is often a significant part of the price of a new refrigerator. Therefore, if your unit is more than 10-12 years old, it is often more profitable to buy new equipment than to invest money in replacing the “heart” of the old one. However, for expensive premium models, replacing the compressor may be justified.
When choosing a new compressor, it is important to consider not only the dimensions and power, but also the type of refrigerant for which the system is designed (R600a or R134a), as well as the type of oil. The use of unsuitable components may lead to incorrect operation of the refrigerator.
Frequently asked questions (FAQ)
Why does the refrigerator compressor get very hot?
Heating of the compressor is a normal operating process, since heat is released when the gas is compressed. The case temperature can reach 70-90 degrees. However, if it is so hot that it is impossible to touch it, or there is a burning smell from it, this may indicate an interturn short circuit of the windings, jamming of the mechanism, or problems with ventilation around the refrigerator.
Is it possible to replace a conventional compressor with an inverter one?
Theoretically this is possible, but in practice it requires a complete rework of the system management. An inverter motor cannot operate from a conventional starting relay and requires an inverter control unit (board) that coordinates the operation of the motor with the thermostat. Such a replacement is not economically feasible.
How long does a compressor last in a refrigerator on average?
The average service life of a modern compressor ranges from 7 to 15 years. Inverter models, due to the absence of constant starts and stops, can operate for up to 20 years or more. The service life directly depends on the quality of the voltage in the network, ventilation conditions and the frequency of defrosting.
What to do if the compressor hums but does not start?
Most likely, the starting relay has failed or the compressor itself has jammed. In the first case, replacing the relay will solve the problem. In the second case, a professional “wedging” or replacement of the unit will be required. You cannot keep the refrigerator turned on in this state - the motor winding will burn out.