The refrigerator is an integral part of modern life, keeping food fresh and providing comfort at kitchen. However, few people think about what makes this box work for years, generating cold in a closed circuit. The central element of the entire system is the compressor, which is often called the “heart” of the refrigeration unit. It is on its proper operation that the device’s ability to maintain a given temperature and the cooling efficiency of the chambers depends.
Understanding the operating principle of this unit helps owners not only be more careful with their equipment, but also respond more quickly to the first signs of malfunctions. In this article, we will look in detail at how a compressor works, what its types are, and why timely diagnosis of problems can save your refrigerator from expensive repairs or complete replacement.
Principle of operation and role in the cooling system
The main task of the compressor is to create a pressure difference in the refrigeration circuit, which allows the refrigerant to circulate through the system. It sucks low-pressure freon gas from the evaporator and compresses it, forcing it into the condenser at high pressure. This compression process is accompanied by a significant increase in gas temperature, which is a natural physical phenomenon during the operation of any pumping equipment.
Refrigerant circulation is a key process without which heat exchange is impossible. The engine drives the piston group or rotates the rotor, forcing the gas to move in a closed circle. In a condenser, usually located on the rear wall, hot gas releases heat to the environment and condenses into liquid. Then, passing through the capillary tube and the evaporator inside the chambers, the refrigerant expands sharply and boils, actively absorbing heat from the products.
⚠️ Attention: If you notice that the compressor works without stopping or, conversely, turns on very rarely, this may indicate a violation of the tightness of the circuit or a malfunction thermostat. Ignoring these symptoms often leads to failure of the motor itself.
The efficiency of the entire system directly depends on the performance of the compressor unit. Modern models are equipped with sophisticated electronics that regulate engine operation depending on the load. Inverter technologies, which will be discussed below, allow you to change the shaft rotation speed, providing more accurate temperature maintenance and reducing energy consumption.
Design features and internal structure
Visually, the compressor is a sealed metal cylinder, usually black, located in the lower rear part of the refrigerator. Inside this casing there is an electric motor and a mechanical part immersed in a special oil. This design is called hermetically sealed, as it eliminates the possibility of freon leaking through the engine shaft, which would be inevitable when using stuffing box seals.
The internal structure may vary depending on the type of compressor, but the classic piston unit consists of the following main elements:
- 🔧 Electric motor - creates a rotational movement that is transmitted to the crankshaft.
- 🔧 Piston group —includes a cylinder, piston and valves that directly compress the gas.
- 🔧 Suspension system —springs on which the motor-compressor is suspended inside the casing, dampen vibrations and reduce noise levels.
- 🔧 Start-protection relay is a device that ensures the engine starts and protects it from current overloads.
The oil located inside the casing performs a dual function: it lubricates the rubbing parts and participates in heat removal. It is important to understand that oil in hermetic compressors is part of the working environment and does not require replacement during the entire service lifeif repairs were not made by opening the circuit. Attempts to add oil through external holes without evacuation of the system will lead to moisture ingress and rapid failure of the equipment.
Copper tubes are suitable for the compressor housing: one or two suction (usually larger diameter) and one discharge (smaller) diameter). Through the suction tube, cold gas from the evaporator enters the compressor, and through the discharge tube, hot compressed gas goes into the condenser.
Main types of compressors: from classics to inverters
The household appliances market offers various options for compressor units. The choice of motor type affects the noise level, energy consumption and durability of the refrigerator. Understanding the differences will help you make the right choice when purchasing or diagnosing a device.
The most common types are:
- ❄️ Piston compressors —the classic version, where compression occurs due to the reciprocating movements of the piston. They are reliable, repairable, but can create noticeable noise and vibration.
- ❄️ Inverter compressors are modern units that can smoothly change the speed of shaft rotation. They do not turn off completely, but only slow down when the desired temperature is reached. This ensures silence and energy savings of up to 20-30%.
- ❄️ Linear compressors - a type where the piston is driven by electromagnetic forces without rotational mechanisms. They are characterized by a minimum number of rubbing parts and low noise levels.
Inverter models, such as Digital Inverter from Samsung or Linear Inverter from LG, are considered more durable, since the absence of constant on and off cycles reduces wear on mechanical parts. However, their electronics are more sensitive to voltage drops in the network, which requires the use of high-quality stabilizers.
⚠️ Attention: When replacing a conventional compressor with an inverter one, it is necessary to resolder the entire control system and install the inverter board. A simple one-to-one replacement is impossible without a deep modernization of the electrical circuit of the refrigerator.
In some models of large-volume refrigerators, two compressors can be installed. This allows you to independently regulate the temperature in the refrigerator and freezer compartments. If one of the motors fails, the second chamber will continue to work, which is a significant advantage in emergency situations.
Why are inverter compressors quieter?
The secret of silence is the absence of sudden inrush currents and sudden starts. The engine always runs at low speeds, maintaining pressure, rather than turning on at full power for rapid cooling.
Fault diagnosis and characteristic symptoms
A compressor is a complex mechanical unit that is subject to wear. Catching problems early can extend the life of your refrigerator. There are a number of signs by which you can determine that the “heart” of your unit is malfunctioning.
The most common symptoms of malfunctions:
- 🔊 Loud knocking or clanging during startup or operation - often indicates wear of the bearings, destruction of the motor mount or liquid freon entering the cylinder (hydraulic hammer).
- 🔥 Intense heating of the housing - if the compressor is so hot that it is impossible to touch it, this may indicate an interturn short circuit in the motor winding or a blockage in the system.
- 🔌 Frequent switching on and off (clocking) - the motor runs for several seconds, then a relay click is heard, and it falls silent. This is a classic sign of a faulty start relay or jamming of the piston group.
It is also worth paying attention to the lack of cold in the chambers when the engine is running. If the compressor is humming, the tubes are hot or cold (depending on the area), but the refrigerator is warm, there may be a freon leak or a clogged capillary tube. In this case, the compressor itself may be operational, but run idle.
Diagnostics of the electrical part, such as checking windings for open circuits or short circuits, should be carried out with caution, having first disconnected the device from the network. A multimeter is used to measure resistance. Normal winding resistance values are usually from 10 to 30 Ohms, but the exact data depends on the specific model.
☑️ Primary diagnostics of the compressor
Comparison table of characteristics of different types
For easy comparison The main characteristics of various types of compressors used in household refrigerators are given in a summary table. It will help you understand what to expect from your equipment or what to look for when choosing a new model.
| Characteristics | Piston (Regular) | Inverter | Linear |
|---|---|---|---|
| Noise level | Medium / High | Low | Very low |
| Energy consumption | Standard | Economical (class A+ and higher) | Economical |
| Operating principle | Cyclic (On/Off) | Smooth speed control | Linear movement of the piston |
| Service life | 7-10 years | 10-15 years or more | 10-15 years or more |
| Sensitivity to voltage surges | Average | High (stabilizer required) | High |
The table shows that modern technologies are aimed at reducing noise and energy consumption. However, this comes at the cost of higher sensitivity of the electronics to the quality of the power grid. In regions with unstable voltage, installing a stabilizer for an inverter refrigerator becomes not just a recommendation, but a necessity.
Operation rules and extending service life
In order for the compressor to serve as long as possible, it is necessary to follow a number of simple but important operating rules. Mechanical wear and tear is a natural process, but improper handling can shorten the life of the unit significantly.
First of all, ensure adequate ventilation. The refrigerator should be positioned at least 5-10 cm from the wall so that the heat from the condenser and the compressor itself can dissipate freely. Overheating is the main enemy of any electric motor. If you notice that the refrigerator is in a niche or close to the furniture, be sure to correct it.
Secondly, avoid frequently opening the door and placing hot foods inside. A sharp increase in temperature inside the chambers forces the compressor to work at its limit in order to restore the mode. This leads to overload and accelerated wear of parts.
⚠️ Attention: Never plug in the refrigerator immediately after defrosting or transporting it if it was transported lying down. The oil should drain back into the compressor crankcase; this requires 2 to 4 hours (or better yet, a day) of standing in a vertical position.
Regularly check the integrity of the door seals. If the rubber band does not fit tightly, warm air constantly enters the chamber, forcing the compressor to work almost non-stop. This “no rest” mode quickly disables the equipment.
Is it possible to wash the compressor with water?
It is strictly not recommended to wet the compressor and electrical parts with water. It is better to carefully remove dust from it with a dry soft brush or vacuum cleaner at minimum power, having first disconnected the refrigerator from the mains.
FAQ: Frequently asked questions
Why does the refrigerator compressor get very hot?
Heating of the compressor is a normal physical process, since when gas is compressed heat is released. The body temperature is considered normal up to 60-70 degrees Solid (the hand is tolerable, but it hurts to hold). If the housing is hot to the point of blackness or there is a burning smell from it, this is a sign of a malfunction: a clogged system, a freon leak, or problems with the motor winding.
Is it possible to replace a conventional compressor with an inverter one?
Technically this is possible, but it is economically and technically impractical for older models. An inverter compressor requires a special control board, which is not found in conventional refrigerators. The cost of such alterations often exceeds the price of a new refrigerator. It is easier and more reliable to install an original or a conventional compressor with similar characteristics.
How often should the compressor be turned on and off?
In conventional refrigerators, the operating cycle is approximately 10-15 minutes of operation and 20-30 minutes of rest. The exact ratio depends on the chamber load, room temperature and thermostat settings. If the refrigerator turns on every 2-3 minutes and immediately turns off, this is an emergency mode that requires the intervention of a technician.
What does hum or vibration mean during operation?
A slight hum is the norm. Strong vibration may be caused by the refrigerator not being level (adjust the feet). A loud knock or clanging inside the compressor often indicates mechanical destruction of components (bearings, piston group) and requires replacement of the unit.