When you hear the usual humming coming from the kitchen, or, conversely, notice suspicious silence, first of all you should think about the condition of the main household appliances unit. It refrigerator compressor is the heart of the entire cooling system, ensuring the circulation of refrigerant through the tubes. Without this compact but powerful unit, it is impossible to create the low temperatures necessary to maintain food freshness.
Understanding how this mechanism works will help you quickly diagnose problems and avoid unnecessary repair costs. In this article we will analyze in detail what types of motors exist, why they fail and how to properly operate the equipment so that it lasts for decades.
Main purpose and principle of operation
The function of the compressor is to compress the gaseous refrigerant and force it to move along a closed circuit of the refrigeration system. At the moment of compression, the gas pressure increases sharply, which is accompanied by an increase in its temperature. After passing through the condenser (the grill at the back of the refrigerator), the refrigerant cools and turns into a liquid state, after which it evaporates again, taking heat from the chambers.
This process is cyclical and is controlled by electronics or a mechanical thermostat. When the temperature inside the chambers rises above a predetermined threshold, the sensor sends a signal to start the engine. Motor-compressor starts working until the desired temperature is reached, after which it turns off. This cycle is repeated continuously as long as the refrigerator is connected to the power supply.
⚠️ Attention: If you notice that the compressor is running non-stop or, conversely, does not turn on at all, this is a direct signal of a thermostat malfunction or a freon leak. Operation in this mode can lead to overheating of the motor windings.
The efficiency of the entire system directly depends on the tightness of the compressor housing and the condition of its internal valves. Even a microscopic gas leak or moisture entering the system can disrupt heat transfer. That is why replacement of the compressor often requires not only the installation of a new unit, but also complete evacuation of the system and refilling with new freon.
Varieties of compressor units
Modern industry offers several types of compressors, each of which has its own design features and energy efficiency characteristics. The most common are piston models, which, in turn, are divided into static and dynamic. Static ones work on the principle of reciprocating motion of the piston, while dynamic ones use rotational motion.
In recent years, inverter compressorsare gaining more and more popularity. Unlike classic models that operate in an on-off mode, inverter motors do not stop completely. They smoothly regulate their power, maintaining the temperature within specified limits. This allows you to significantly reduce the noise level and energy consumption.
- 🔹 Piston compressors are a classic proven technology, available in maintainability, but noisier.
- 🔹 Inverter compressors are quiet, economical, durable, but sensitive to voltage drops in networks.
- 🔹 Linear - a type of piston without rotational movements, characterized by a low level of vibration.
It is also worth mentioning rotary (screw) compressors, which are more often found in industrial installations or large-volume refrigerators. They provide high performance and stability under heavy loads. The choice of a specific type depends on the model of the refrigerator, its volume and price segment.
Design and key elements
Visually, the compressor is a black metal barrel located in the lower rear part of the refrigerator. Inside this sealed casing are the electric motor and the compressor mechanism itself, immersed in special oil. Oil is necessary to lubricate rubbing parts and remove heat, as well as to ensure additional tightness.
The main design elements include:
- 🔸 Housing - a sealed welded casing that protects internal components from dust and moisture.
- 🔸 Electric motor - creates torque moment to drive the compression mechanism.
- 🔸 Piston group (or rotor) - directly compresses the refrigerant.
- 🔸 Start-up relay - a device that provides engine starting and overload protection.
An important element is start relay, which supplies an impulse to the starting winding of the engine at the moment of start. Without this component, the engine will not be able to gain the required speed. The design also includes suction and discharge pipes, through which the refrigerant enters and exits the compressor under high pressure.
The tightness of the housing is a critical parameter. Factory welding eliminates the possibility of independently opening and repairing internal components without special equipment. That is why, when internal parts break down, a complete replacement of the compressor assembly is usually performed, rather than overhauling it.
Comparative table of characteristics
For a better understanding of the differences between the main types of engines used in household refrigerators, let's consider their technical parameters in comparison. This will help evaluate the advantages and disadvantages of each option when choosing equipment.
| Parameter | Normal (Start-Stop) | Inverter | Linear |
|---|---|---|---|
| Noise level | Medium / High | Low | Very low |
| Energy consumption | Standard | Economical (up to -30%) | Economical |
| Service life | 7-10 years | 10-15 years or more | 10-15 years |
| Sensitivity to networks | Low | High (stabilizer needed) | Medium |
As can be seen from the table, inverter models win in most respects, but their cost and the price of spare parts are much higher. Conventional compressors are more “omnivorous” in terms of the quality of electricity, which is important for regions with an unstable network.
Why is an inverter compressor quieter?
It does not experience constant peak loads at each start-up, since it operates continuously, but with different intensities, which eliminates loud clicks and start-up hums.
Typical malfunctions and symptoms
Despite the reliability of modern units, the resource of any mechanism is not endless. Most often, owners are faced with a problem when the refrigerator does not freeze, and the compressor either does not turn on or runs in vain. One of the common reasons is the failure of the starting relay, which can be replaced independently if you have the skills.
A more serious problem is the interturn short circuit of the motor winding. In this case, the motor may hum and try to start, but then the thermal protection is triggered and it turns off. A characteristic sign is strong heating of the compressor housing and a burning smell. In such a situation, professional diagnostics are required.
⚠️ Attention: An attempt to independently repair the sealed compressor housing or solder tubes without a vacuum sealer will lead to moisture entering the system and complete breakdown of the refrigerator in the shortest possible time.
Freon leakage through microcracks in the circuit is also common. In this case, the compressor works constantly, trying to catch up with the temperature, but no cooling occurs. Long-term operation in this mode leads to overheating and combustion of the engine.
- 🔴 Loud knocking or clanging during operation - wear of the piston group or valves.
- 🔴 The compressor is hot, but the refrigerator is not cold - a refrigerant leak.
- 🔴 Clicks and does not start - faulty relay or starting capacitor.
Care and extending service life
In order motor-compressor to serve as long as possible, it is necessary to provide it with the correct operating conditions. First of all, this concerns heat dissipation. The back wall of the refrigerator, where the condenser and the compressor itself are located, must have free access to air. Installing equipment close to a wall or in a niche without gaps leads to overheating.
Regular cleaning of the condenser grille from dust and pet hair is also critically important. A layer of dust several millimeters thick can impair heat transfer by 20-30%, causing the compressor to work longer and harder. It is recommended to carry out such cleaning once every six months.
In addition, you should avoid frequently turning the refrigerator on and off from the outlet. Sudden voltage surges when starting a cold engine create a maximum load on the windings. If you need to turn off the equipment, do this through the thermostat or let it stand turned off for several minutes before turning it on again.
☑️ Checking the operating conditions of the compressor
Compliance with the temperature regime in the room also plays a role. Installing the refrigerator next to heating appliances or in direct sunlight forces the cooling system to work at its limit, reducing the life of the compressor.
FAQ: Frequently asked questions
Is it possible to replace a conventional compressor with an inverter one?
Theoretically this is possible, but in practice it requires a complex reworking of the control system. Inverter models require a special controller, which is not found in conventional refrigerators. A simple one-to-one replacement is impossible without a deep modernization of the electronics.
Why does the compressor get very hot?
Heating up to 70-90 degrees for the upper part of the case is the norm during active operation. If the temperature exceeds 100 degrees or the entire casing becomes hot, this may indicate a freon leak, a malfunction of the thermostat, or contamination of the condenser.
How much does it cost to replace a compressor?
The cost consists of the price of the unit itself and the work of the technician. On average, replacement costs 40-60% of the cost of a new refrigerator. For older models, repairs are often not economically feasible.
Is the new compressor humming - is this normal?
New models, especially those with inverter control, may make sounds similar to gurgling or low-frequency hum. This is the sound of freon moving through the system. If the humming is not accompanied by vibration of the refrigerator body and does not interfere with sleep, this is normal.