When the inside of the chamber suddenly becomes warmer, and the characteristic hum disappears on the back wall, the first thing the owner thinks about is that the motor has broken down. It is refrigerator motor, or, technically speaking, the compressor, that is the heart of the entire cooling system. Without its continuous operation, the refrigerant will not be able to circulate through the tubes, taking heat from the products and releasing it into the environment. Understanding the principles of operation of this unit helps not only diagnose a malfunction, but also save significant money on calling a technician for basic checks.
Modern units can be equipped with various types of drives, from classic piston drives to innovative inverter systems. Atlant, Bosch, Liebherr —regardless of the brand, the physics of the process remains the same similar, although design solutions may differ radically. In this article, we will look at what exactly causes cold to appear inside your kitchen, why the motor hums, clicks or is silent, and whether it is possible to extend its life with proper operation.
The basic principle of the compressor
The fundamental task of the engine is to create a pressure difference in the system. It compresses the freon gas, forcing it under high pressure into the condenser (heat exchanger on the back wall). There the gas cools and turns into a liquid, after which it passes through the capillary tube and throttle, expanding sharply in the evaporator. It is at the moment of expansion that active absorption of heat from the internal volume of the chambers occurs. This cycle is repeated until the thermostat registers the achievement of the set temperature.
Inside the sealed housing there is not only the electric motor itself, but also a piston group immersed in oil. Oil necessary for lubrication of rubbing parts and heat removal. When started, the engine rotor begins to rotate, driving the crankshaft, which pushes the pistons up and down. It is important to understand that the pressure at the outlet of the compressor can reach several atmospheres, which makes the system potentially dangerous if opened improperly.
⚠️ Attention: It is strictly forbidden to open the sealed compressor casing or try to drill holes in it. There may be pressurized refrigerant inside, and oil vapors may be toxic. Repair by “opening” the housing at home is impossible and leads to complete disposal of the unit.
Circulation of the refrigerant is impossible without creating pressure. Compressor works like a pump, but it pumps not water, but gas. The efficiency of this process directly affects the freezing speed and energy consumption. If the engine operates intermittently, the temperature in the chambers begins to “float”, which is detrimental to the products.
Engine types: piston and inverter
Two main types of drives dominate the household appliances market. The classic version is piston compressor. It works on the principle of “turned on - worked at full power - turned off.” This cyclicity creates a characteristic noise when starting and stopping, and also causes voltage surges in the electrical network. Despite the noise, these models are distinguished by high maintainability and low replacement cost.
A more modern solution is inverter motor. It does not turn off completely, but only reduces the speed to a minimum, maintaining the temperature. This ensures silence, absence of vibrations and significant energy savings. However, the electronics of such systems are extremely sensitive to voltage drops in the network, which requires the installation of a high-quality stabilizer.
- 🔇 Noise level: Inverter models operate almost silently, unlike loud piston analogues.
- ⚡ Energy efficiency: Smooth power adjustment allows you to save up to 30% of electricity.
- 🛠️ Resource: The absence of constant starting loads extends the service life of moving parts.
The choice between engine types is often dictated budget. Inverter technologies are more expensive, but pay off in the long run. It is worth noting that some budget models may use linear compressors, which occupy an intermediate position in terms of noise and reliability characteristics.
Design and main components of the engine
Externally, the engine is a black metal “barrel”, to which tubes and an electrical cable are suitable. There is a vacuum inside this casing, which prevents oxidation of parts. The main element is electric motorwhich converts electrical energy into mechanical rotation. A piston group is suspended from the motor shaft through a system of springs.
The starting relay deserves special attention. This small plastic block, placed over the motor contacts, is responsible for sending an impulse to the starting winding. Without this impulse, the rotor would simply hum, but would not begin to rotate. The design also contains copper tubes (suction and discharge), through which freon enters and leaves the compressor.
| Element | Function | Signs of malfunction |
|---|---|---|
| Start relay | Starting the engine | Clicks, humming without starting |
| Piston group | Freon compression | Weak cooling, knocking |
| Windings motor | Creation of a magnetic field | Lack of reaction, burning smell |
| Oil | Lubrication and cooling | Overheating, jamming |
The tightness of the case is a key factor in durability. If a microcrack appears in the system, moisture and air penetrate inside. This leads to the formation of an acidic environment, which destroys the windings and clogs the capillary system. Therefore, any manipulations with tubes require the use of nitrogen and professional equipment.
Why does the compressor hang on springs?
Inside the casing, the motor is suspended on springs to dampen vibrations. If the spring bursts or jumps off, the refrigerator will begin to vibrate and rattle strongly, even if the engine itself is working.
Malfunction symptoms and diagnostics
You can determine what refrigerator motor requires intervention by a number of indirect signs. The most obvious is a change in temperature. If food spoils faster, and there is no frost on the walls (in No Frost models) or, conversely, everything is frozen in a lump (in drip models), the problem may be in the performance of the compressor.
Acoustic anomalies are also eloquent. A loud metallic clanging sound when turned on often indicates worn bearings or a damaged suspension. If the motor hums for 5-10 seconds, then a click is heard and silence sets in - this is a classic symptom of a “wedge” or a burnt-out start relay. The motor tries to start, the current increases, and the thermal relay emergency opens the circuit.
- 🔥 Overheating: The motor body is hotter than 80-90 degrees.
- 🔌 Knocking out plugs: A short circuit in the windings triggers the circuit breakers in the panel.
- 🌫️ Bloating: Deformation of the compressor housing indicates critical internal pressure.
⚠️ Attention: If, when you try to start, the refrigerator makes a loud bang and knocks out electricity, immediately unplug it. Further switching on may lead to a fire in the wiring.
Diagnostics should begin with a visual inspection and checking the voltage at the contacts. However, to accurately measure winding resistance and freon pressure, you will need a multimeter and a pressure gauge station. Without these tools, we can only guess the nature of the breakdown.
Why the engine does not turn on or off
The situation when the refrigerator is silent does not always mean the death of the compressor. Often the problem lies in the control circuits. The thermostat may simply not give the command to turn on if it is already cold in the chamber. In modern models, an electronic control module is responsible for this, which can block startup in the event of sensor errors.
Another common reason is thermal relay. It protects the motor from overheating. If the refrigerator was in a hot room or the condenser was clogged with dust, the relay could trip and cut off the power. After cooling (after 30-60 minutes), work is usually restored. If the motor clicks and stalls constantly, most likely the piston group is jammed.
☑️ Primary diagnosis of a silent refrigerator
It is important to distinguish between normal shutdown and emergency shutdown. The normal operation occurs smoothly after reaching temperature. Emergency - always accompanied by extraneous sounds, odors or lack of cooling after a long period of inactivity.
Replacement and repair: is it worth the candle
Repairing the compressor itself in a service center is possible, but not economically feasible. The cost of rebuilding, replacing valves and vacuuming often exceeds the price of a new unit. Therefore, the industry standard is complete replacing the unit. This requires a vacuum pump, a supply of freon and skills in soldering copper pipes.
When replacing, it is important to choose a model with similar cooling capacity and overall dimensions. Installing a more powerful engine will lead to frequent starts and rapid wear, while a weak one will result in an inability to maintain temperature in hot weather. Also, the filter drier must be changed, since the old one has already accumulated moisture and will not be able to work effectively.
Critical important: After soldering and replacing the compressor, the system must be vacuumed for at least 15-20 minutes. Residual moisture in the tubes will turn into an ice plug or acid, which will kill the new compressor in a few months.Prevention and extension of service life
In order refrigerator motor to serve the stated 10-15 years, it is necessary to provide it with comfortable conditions. The main rule is the temperature of the room. Installing the unit next to a radiator, stove, or in direct sun forces the motor to work at the limit, which sharply reduces the resource.
Regular cleaning of the condenser (grid at the back) of dust and animal hair improves heat transfer. If the heat does not leave, the pressure in the system increases and the load on the piston group increases. Also, you should not load a large amount of warm food into the chamber at the same time - this causes the motor to run for a long time without stopping.
- 🧹 Cleanliness: Vacuum the rear grille every six months.
- 📏 Gap: Leave at least 10 cm from the wall for ventilation.
- 🧊 Defrosting: Do not allow the formation of a “fur coat” thicker than 5 mm.
Following these simple rules will avoid premature wear (premature wear) and expensive repairs. Remember that stable operation of the compressor is the key to the freshness of your products.
How long does a compressor last on average?
The average service life of a modern compressor is from 10 to 15 years. Inverter models can operate for up to 20 years due to the absence of peak loads at start-up. However, the real figure greatly depends on the quality of the electrical network and operating conditions (temperature in the room, cleanliness of the condenser).
Is it possible to replace the compressor with another brand?
Yes, you can, but subject to the following conditions: matching power (cooling capacity in BTU or Watts), type of refrigerant (R134a, R600a), overall dimensions and tube diameters. Often, craftsmen use universal compressors, for example, from Secop (formerly Danfoss), which are suitable for many models.
Why does the compressor get very hot?
Heating up to 70-90 degrees is the norm for a running motor. If it is hot (you cannot touch it), the reasons may be: a malfunction of the thermostat (the motor does not turn off), a freon leak (the motor runs without stopping), a clogged capillary, or poor rear ventilation.
Is the humming of a compressor dangerous?
Uniform humming is a sign of normal operation. Sudden changes in sound are dangerous: metallic clanging, squealing, gurgling or intermittent buzzing with clicks. These sounds indicate mechanical destruction of internal parts or problems with starting.