The heart of any refrigeration system is the compressor. It is this unit that creates the necessary pressure for the circulation of the refrigerant, turning gas into liquid and back, which allows maintaining a low temperature in the chambers. When you hear a characteristic hum or knocking noise coming from the rear panel, you know: it's working refrigeration unit. Without a working motor, the cooling process becomes impossible, and food quickly deteriorates.
Visually it is a black metal cylinder, often with copper tubes coming out of the body. However, the internal structure may differ dramatically depending on the model and manufacturer. Understanding how a compressor workshelps not only when choosing new equipment, but also when diagnosing faults. In this article we will analyze the design in detail, provide photos of various modifications and explain the principles of their operation in simple language.
The modern market offers many options, from classic piston to inverter systems. Inverter compressors are able to change the shaft rotation speed depending on the temperature in the chamber, which significantly saves energy. Understanding the variety of technologies is not easy, but knowing the basic principles will allow you to feel more confident when using communicating with a technician or when purchasing a new refrigerator.
Main purpose and principle of operation
The main task of the compressor is to compress and pump refrigerant vapors. It sucks freon gas from the evaporator, compresses it and sends it under high pressure to the condenser. There the gas cools and turns into liquid, releasing heat to the environment. This continuous cycle provides heat removal heat removal from the interior of the refrigerator.
The compression process is accompanied by heating, so the body of the device is always hot during operation. It is important to understand that outlet pressure is significantly higher than at the inlet, which forces the refrigerant to move through the system. If this balance is disturbed, the cooling efficiency drops and the equipment ceases to cope with its task.
⚠️ Attention: When the compressor operates, the oil inside the crankcase heats up. If you plan to transport the refrigerator, be sure to let it stand in an upright position for at least 4-6 hours before turning it on, so that the oil flows back into the crankcase and does not enter the circulation circuit.
The efficiency of operation directly depends on the tightness of the system. Even a microscopic freon leak causes the motor to overload, trying to gain the required pressure. That is why diagnostics of tightness is the first step in repair.
Device and internal design
Most household refrigerators are equipped with hermetic compressors. This means that the electric motor and mechanical part are housed in a single steel casing, which is welded at the factory. Disassembling such a housing at home is practically impossible without damaging the seal, so if it breaks, the entire assembly is usually replaced.
Inside the casing there are the following key elements:
- ⚙️ Electric motor — drives the shaft, creating the necessary force.
- ⚙️ Crank mechanism — converts the rotational movement of the shaft into the translational movement of the piston.
- ⚙️ Valve system — ensures the movement of freon in only one direction.
- ⚙️ Oil system —lubricates rubbing parts and removes heat.
The photographs of the sections show that the engine shaft is immersed in oil, which splashes when rotating. This ensures lubrication of bearings and cylinders. Oil quality and its quantity is critically important: a lack of lubrication leads to jamming, and excess leads to oil getting into the circuit and worsening heat transfer.
Why do compressors weld?
A sealed casing is necessary to prevent refrigerant leaks and protect internal mechanisms from dust and moisture. In addition, the steel shell acts as a noise muffler, reducing acoustic discomfort during operation of the equipment.
Main types of compressors
Technologies do not stand still, and today several types of engines can be found in refrigerators. The choice of a specific type affects the noise level, energy consumption and durability of the equipment. Let's look at the main types that are found on sale.
The most common remain piston compressors. They are time-tested, inexpensive to produce, and repairable (although repairs are often unprofitable). Their operation is accompanied by characteristic clicks when starting and stopping. At the same time, linear compressors, popular with the LG brand, work without a crank mechanism, moving the piston linearly due to electromagnetic forces. This reduces the number of rubbing parts and the level of vibration.
Deserve special attention inverter models. Unlike classic ones, which operate on the “on-off” principle, the inverter motor does not stop completely. It only reduces the speed, maintaining the temperature. This ensures:
- 🔇 Significantly quieter operation without sudden starting currents.
- ⚡ Energy savings of up to 25-30%.
- 🌡️ More accurate temperature maintenance mode.
- 📉 Less wear on mechanical parts.
Comparative characteristics of models
To better understand the differences between technologies, it is worth turning to specific numbers and parameters. Below is a table comparing the main characteristics of various types of units installed in household appliances.
| Parameter | Piston (Start-Stop) | Inverter | Linear |
|---|---|---|---|
| Noise level | Medium / High | Low | Very low |
| Energy consumption | Standard | Economical (Class A+ and above) | Economical |
| Work life | 10-15 years | 15-20 years | 15-20 years |
| Repair cost | Low / Medium | High | High |
As can be seen from the table, modern technologies win in terms of comfort and savings, but lose in the price of the device itself and spare parts. Replacing an inverter compressor will cost the owner much more than installing a conventional analogue. However, the long-term perspective often justifies the investment.
It is worth noting that two-compressor refrigerators have two separate motors: one for the refrigerator compartment, the other for the freezer. This allows you to independently regulate the temperature and turn off one of the chambers while the other continues to work. Single compressor systems they use one motor and a flow distribution system, which is cheaper, but less reliable in case of breakdown.
Fault diagnosis
You can determine that the compressor has failed by a number of signs. The most obvious is that the refrigerator has stopped freezing, but the light inside is on. If you hear that the motor is trying to start, hums, clicks and immediately turns off, this is a sure sign interturn short circuit or a wedge mechanism.
Sometimes the unit works constantly without turning off. This may indicate a freon leak or loss of performance of the compressor itself. He simply cannot gain the required pressure. You can check this by touching the condenser grille from behind: it should be uniformly warm. If it is cold or warm only at the entrance, the problem is circulation.
⚠️ Attention: Never try to check the performance of the compressor by connecting it directly to the network without a start relay and protection. This may result in electric shock or fire due to lack of pressure and temperature control.
Also pay attention to the smell. If the back wall smells of scorched wiring or burnt oil, this is a signal that the windings are overheated. Thermal relay in such a situation it should work and turn off the power, but if it is faulty, the consequences can be serious.
☑️ Signs of a malfunction compressor
Replacement and installation rules
The process of replacing a compressor is a complex technical procedure that requires special tools. To carry it out you need:burner, pipe cutter, rolling, vacuum pump, pressure gauge station, refrigerant. Simply “unscrewing and screwing” will not work here, since the system must be absolutely sealed and dry.
First, the technician pumps out the remaining freon (if it is still there) and purges the circuit with nitrogen, removing combustion products and moisture. Then the new unit is sealed. It is important to use a torch with a flame at the correct temperature to avoid burning the tubes. After soldering, the system is vacuumized for 15-20 minutes to remove moisture and air.
Only after creating a vacuum, the accurately calculated amount is charged refrigerant. Overfilling or underfilling will lead to malfunction or breakdown of the new compressor. Refrigerant type (R600a, R134a) must strictly comply with the markings on the refrigerator nameplate.
Modern refrigerators are often equipped with electronics that can block the start of a new motor if errors are not reset. In such cases, it is necessary to connect diagnostic equipment via the interface Service Mode. Without this, the equipment may “think” that the compressor is faulty and not apply voltage to it.
Frequently asked questions (FAQ)
Why does the compressor get very hot?
Heating to 60-90 degrees is the norm for a working unit, since gas is released during compression warm. However, if the housing is hot beyond touching or smells burning, this may indicate a malfunction of the thermostat, a freon leak, or engine wear.
Is it possible to replace a conventional compressor with an inverter one?
Theoretically it is possible, but technically it is extremely difficult and expensive. The entire control board will need to be replaced, since conventional boards cannot control the inverter motor. Economically, such a replacement is not feasible; it is easier to buy a new refrigerator.
How long does a compressor last on average?
The average service life of a high-quality compressor is 10-15 years. Inverter and linear models can operate for up to 20 years or more, subject to operating conditions and a stable network voltage.
Is it dangerous to touch a running compressor?
It is safe to touch the housing of a running compressor if it is in good working order and grounded. However, it is better not to pour water on a hot surface or touch it with wet hands to avoid burns or short circuits if the insulation is damaged.