The heart of any household refrigerator, be it an old Soviet unit or a modern one Smart gadgetis the compressor. This unit is responsible for circulating the refrigerant through the system, creating the necessary pressure to remove heat from the chambers. Understanding how a refrigerator compressor works allows the owner of the equipment not only to diagnose the first signs of a malfunction, but also to extend the life of the equipment.
Many users take the hum of a running motor for granted, but the nature of the sound, the frequency of switching on and the temperature of the case can tell a lot about the condition of the insides of the unit. Sealed unit, which we see from behind, hides a complex mechanical system that requires precise lubrication and proper thermoregulation for stable operation.
In this article we will analyze in detail the anatomy of the compressor, consider the differences between conventional and inverter models, and also discuss why self-repair of this unit is often impossible at home. Knowledge of the device will help you avoid costly mistakes during operation.
The principle of operation of the compressor in the cooling system
The main task of the compressor is to compress and pump gaseous refrigerant. The cycle begins with the fact that freon in a gaseous state it enters the suction tube from the evaporator. Here the pressure is low, and the temperature of the steam is relatively high after it has taken heat from the products.
Once inside the housing, the gas is compressed by the piston group. The pressure increases sharply, which leads to an increase in gas temperature. The hot, compressed freon is then pushed into the condenser (the radiator at the back of the refrigerator), where it cools and turns into a liquid. This process is continuous and is regulated by a thermostat.
⚠️ Attention: The housing of a working compressor can heat up to 90°C or higher. Do not touch metal parts immediately after stopping the engine to avoid burns.
The key element here is the pressure difference: at the inlet it is minimal, at the outlet it is maximum. It is this difference that causes the refrigerant to move in a closed circuit, providing cooling to the chambers. Violation of the tightness of any connection leads to a complete stop of the cycle.
Design and main components of the unit
Visually, the compressor is a black metal cylinder, often pear-shaped. Inside this sealed casing is the electric motor itself and the mechanical compressor part. All of them are immersed in a special compressor oilwhich lubricates the rubbing parts and removes heat.
Three tubes approach the body from the outside: two copper (suction and discharge) and one steel (refill, sealed during production). Also located at the bottom is a terminal block for connecting electricity and a start relay. Disassembling the casing at home is almost impossible without damaging the seal.
Inside the cylinder, the engine drives the piston through the crankshaft. The piston performs a reciprocating motion, sucking in gas and compressing it. Valve system strictly controls the direction of flow, preventing the gas from returning back into the cylinder after compression.
Why are compressors painted black?
Black The color of the case was not chosen by chance. Firstly, it provides excellent corrosion protection. Secondly, the dark surface radiates heat better, helping to cool internal components naturally, although the main function of color is anti-corrosion and marking.
Types of compressors: linear and inverter
Technology does not stand still, and today two main types of drives dominate the market. Understanding their differences will help you choose the right equipment and correctly assess its reliability.
- 🔹 Linear (classic): They work on the “on-off” principle. The motor reaches maximum speed, cools the chamber to the set temperature and turns off. They are characterized by noticeable noise at start-up and power surges in the network.
- 🔹 Inverter: They work constantly, but with a variable shaft rotation speed. They do not turn off completely, but only reduce the speed to maintain the temperature. This ensures silence and energy savings of up to 30%.
- 🔹 Linear-inverter: Hybrid version, where the piston moves without a rotating mechanism, which reduces friction and wear of parts.
Inverter models, such as those used in refrigerators LG or Samsung, are considered more durable due to the absence of constant peak loads at start-up. However, they are sensitive to voltage changes in the electrical network and require the installation of a stabilizer.
Starting system: starting and thermal relay
In order for the motor rotor to move, a powerful impulse. This function is performed by the starting relay. In older models it can be electromechanical, in new ones it can be electronic. It is this small block that often causes the refrigerator to hum but not start.
A thermal protection relay operates in parallel with the starting one. Its task is to break the power circuit if the current in the motor windings exceeds the norm (for example, when the piston is jammed or the network is overloaded). This prevents the windings from burning out and causing a fire.
Checking the relay is often the first step in diagnosis. If, when you turn on, you hear a click, followed by a hum, and after a few seconds - another click and silence, most likely the problem lies in the starting mechanism or in the motor itself.
Characteristics table and comparison of types
For a clear comparison of the various parameters of compressor units, let's refer to the table. It will help systematize knowledge about the differences in operation and maintenance.
| Parameter | Linear (On/Off) | Inverter | Linear-inverter |
|---|---|---|---|
| Level noise | High at start | Low, even hum | Minimal |
| Energy consumption | Standard | Economical (class A++) | Maximum economical |
| Wear of parts | High (frequent starts) | Low | Extreme low |
| Temperature accuracy | Accuracy 2-3°C | Accuracy 0.5°C | Ideal accuracy |
As can be seen from the data, modern technologies are aimed at reducing noise and energy consumption. However, the cost of replacing a compressor can be up to 70% of the price of a new refrigerator, which makes repairing them economically unfeasible in older models. There are a number of indirect signs that the refrigerator compressor is “dying.” First of all, pay attention to the operating mode: if the engine runs without a break for days, and the cold does not build up, this is an alarming signal. linear-inverter Compressor repairs can be up to 70% of the price of a new refrigerator, which makes their repair economically impractical in older models.
Diagnosis of faults and signs of breakdown
You can determine that the refrigerator compressor is “dying” by a number of indirect signs. First of all, pay attention to the operating mode: if the engine runs without a break for days, and the cold does not build up, this is an alarming signal.
The second sign is a characteristic knocking or clanging sound inside the black cylinder. This may indicate a loose engine mount or a damaged valve group. You should also be wary if the compressor does not start at all, although the indicators are on.
- 🔸 Overheating: The housing becomes so hot that it is impossible to touch it (above 100°C).
- 🔸 Knocking out plugs: When you try to start the motor, a short circuit occurs in the network.
- 🔸 Oily traces: The appearance of oil under the refrigerator indicates depressurization of the compressor housing.
⚠️ Attention: If you smell burning wiring or see sparking in the terminal box area, immediately unplug the refrigerator. Further operation is a fire hazard.
Often the cause of breakdown is not the motor itself, but a freon leak. In this case, the compressor runs idle, trying to build up pressure, overheats and burns out. Therefore, replacing the motor without finding and eliminating the leak is a waste of money.
☑️ Symptoms of a faulty compressor
Is it possible to repair it yourself?
The issue of compressor repair often causes controversy. Theoretically, anyone with a screwdriver can replace the start relay or clean the contacts. However, a full repair of the compressor itself (rewinding the engine, replacing the piston group) at home is impossible.
To replace the unit itself, you need:
- A special tool for rolling copper tubes.
- A vacuum pump to remove air and moisture from the system.
- Gas station with precise scales for dosing freon.
- Skills in working with an open flame (torch) for soldering.
In addition, the process requires precise knowledge of the type and amount of oil, as well as the brand of refrigerant. An error in gramming or using the wrong oil will lead to rapid failure of the new part. Therefore replacement of the compressor is a job for the service center.
The only thing you can do yourself is to check the integrity of the windings with a multimeter (if you have access to the contacts) or replace the start relay if you know exactly the model of your refrigerator. But even in this case, the risk of making a mistake is great.
Prevention and extension of service life
In order for the compressor to serve the stated 10-15 years, you must follow simple operating rules. The main enemy of the compressor is frequent switching on and off, as well as overheating.
Do not place the refrigerator close to the wall. A gap of 10-15 cm is necessary for free air circulation around the condenser and motor. If heat is not dissipated, performance will decrease and wear will increase.
⚠️ Attention: Do not load freshly cooked hot food into the chamber. This forces the compressor to work at its limit to compensate for the sudden jump in internal temperature.
It is also important to keep the rear grille clean. The dust layer acts as a heat insulator, interfering with cooling. Regular dry cleaning with a vacuum cleaner or brush will help maintain optimal temperature conditions.
Why does the compressor vibrate strongly?
Vibration can be caused by loosening of the mounting bolts on which the motor is suspended inside the casing, or by the destruction of rubber shock absorbers. In rare cases, this is a sign of wear on the crankshaft bearings.
Is it possible to replace the old compressor with a more powerful one?
Absolutely not. The compressor power must strictly correspond to the volume of the evaporator and condenser. Installing a more powerful motor will lead to freezing of the system and rapid breakdown.
How much does it cost to replace a compressor?
The cost consists of the price of the part itself (from 3,000 to 15,000 rubles, depending on the type) and the cost of work with consumables (freon, oil, soldering). On average, replacement costs 40-60% of the cost of a new refrigerator.
Is the compressor humming - is this normal?
A steady hum is normal. A crackling, clanging, whistling or intermittent noise with pauses indicates a mechanical malfunction of internal parts or problems with the start relay.