When you open the refrigerator door to to get food, you rarely think about the complex mechanism that ensures the safety of your food. Behind the constant cold is the continuous operation of one key unit, which is often called the “heart” of a household appliance. It is this unit that creates the pressure necessary to circulate the refrigerant in a closed circuit, taking heat from the chambers and throwing it out.
Understanding how it works and works compressor in the refrigeratorwill help you quickly diagnose faults, avoid expensive repairs, or wisely choose new equipment. In this article, we will analyze in detail the internal structure of the motor, compare different types of motors and discuss typical problems faced by owners of household appliances.
Knowledge of the basic principles of thermodynamics and mechanics inherent in the design of these devices allows you to operate the refrigerator more efficiently. You will learn to distinguish a normal operating hum from alarming symptoms that foreshadow an imminent breakdown, and you will understand why timely maintenance is so important.
The principle of operation and design of the compressor
The operation of any refrigeration unit is based on a cyclic change in the state of the refrigerant. Compressor plays a role in this system a pump that forcibly moves freon, compressing it and increasing the temperature. The gaseous refrigerant, leaving the evaporator inside the chamber, enters the suction tube of the motor, where it is compressed to high pressure.
After compression, the hot gas under high pressure is pushed into the condenser (the black lattice radiator on the rear wall), where it cools and turns into a liquid state. This process is possible only due to the creation of a pressure difference, which is provided by a piston group or a spiral mechanism inside a sealed casing.
Structurally, the device consists of an electric motor and a mechanical compressor part, enclosed in a single steel housing. Inside there is oil that lubricates rubbing parts and helps remove heat. It is important to note that the housing is completely sealed, and opening it yourself without special equipment is impossible and dangerous.
Why is the compressor housing black and rough?
The black color and rough texture of the outer surface of the casing were not chosen by chance. This special coating improves heat transfer, making it possible to more effectively dissipate the heat that is generated during operation of the electric motor and gas compression.
Inside the casing there is also a start-up relay and a capacitor that control engine starting and protect the windings from overloads. If you hear a click before starting or stopping the motor, this is precisely the work of the relay that switches the electrical circuits.
Main types of compressors: inverter and conventional
The modern household appliances market is dominated by two main types of motors, each of which has its own advantages and disadvantages. Traditional linear (regular) compressors operate on the principle “turned on - worked at full power - turned off”. When the temperature in the chamber rises above the set one, the relay supplies current, the motor starts and runs until the desired cold is reached.
Inverter models, on the contrary, operate constantly, but with a variable shaft rotation speed. The electronics smoothly regulate the engine power depending on the current thermal load. This allows you to avoid sudden changes in temperature and significantly reduces the noise level.
- 🚀 Linear compressors: cheaper to manufacture and repair, but create more noise and vibration, and also have higher power consumption due to starting currents.
- ❄️ Inverter compressors: provide more accurate temperature maintenance, operate quieter, last longer thanks to the absence of constant starting loads, but are sensitive to voltage drops in the network.
- 🔧 Maintainability: conventional motors can often be rewinded or replaced with parts, while inverter units are often replaced entirely due to complex control electronics.
When choosing equipment, it is worth considering that inverter technology it is becoming a standard for the premium segment. However, if your region has an unstable power supply, the good old linear unit may be more durable if a stabilizer is used.
Comparative table of characteristics
For ease of selection and understanding of the differences, we will summarize the main parameters in a single table. This will help you quickly navigate the technical nuances if you are planning a purchase or diagnostics.
| Characteristics | Linear (Normal) | Inverter |
|---|---|---|
| Operating principle | Cyclic (On/Off) | Smooth power adjustment |
| Noise level | Medium / High | Low |
| Energy consumption | Standard (Class A/A+) | Economical (Class A++/A+++) |
| Service life | On average 10 years | Up to 20 years or more |
| Sensitivity to the network | Low | High (stabilizer needed) |
As can be seen from the data, progress is obvious, but the cost of equipment with an inverter motor is higher. However, the overpayment often pays off due to lower electricity bills and no need for frequent servicing.
Typical faults and their symptoms
Even the most reliable mechanism can fail. Understanding the symptoms allows you to notice the problem in time. Most often, owners are faced with a situation where the refrigerator stops freezing, but the light inside is on. This is the first signal that compressor does not start or does not perform its function.
One of the common problems is a break or inter-turn short circuit of the electric motor windings. In this case, the engine may hum, trying to start, but then the relay clicks and it goes silent. Another common reason is the failure of the starting relay or thermostat.
- 🔊 Extraneous sounds: knock, clanging or metallic grinding indicates mechanical wear of the piston group or destruction of the valves.
- 🔥 Overheating of the housing: if the motor casing is hot to the point where it is impossible to reach it touch, this may indicate an interturn short circuit or problems with the cooling system of the compressor itself.
- 💧 Oily traces: the appearance of oil around the tubes leaving the compressor indicates depressurization of the system, which requires immediate intervention from a technician.
⚠️ Attention: If you smell burning or see sparking in the compressor area, immediately unplug the refrigerator! Operation of faulty electrical equipment can lead to a fire.
It is also worth mentioning the so-called “hydraulic hammer”. This happens if liquid freon enters the compressor cylinder instead of gaseous freon. This is possible due to improper refueling or severe violation of the temperature regime, which leads to rapid destruction of the valves.
Diagnostics and performance testing
Before calling a technician or buying a new unit, you can carry out initial diagnostics. For this you will need a multimeter. The first step is to make sure that the problem is in the motor, and not in the lack of voltage in the socket or a malfunction of the thermostat.
The check begins with a visual inspection and continuity testing of the windings. There are three terminals on the compressor housing: two for the working and starting windings, and one common. The resistance between them must be within certain limits (usually from 10 to 30 Ohms). If the multimeter shows an open (infinity) or short circuit (zero), the motor is faulty.
Sequence of checking with a multimeter:1. Disconnect the refrigerator from the network.
2. Remove the protective cover from the rear.
3. Remove the start relay.
4. Measure the resistance between the contacts.
5. Check the resistance between the terminals and the body (there should be a “break”).
Another test method is direct start. If the windings are intact, but the motor does not start through the standard relay, you can try to start it directly by applying voltage to the working winding. This method is dangerous and requires skills, as there is a risk of getting an electric shock or damaging a working motor due to incorrect switching.
☑️ Primary diagnostics of the compressor
Replacing the compressor: difficulties of the process
Replacing a compressor is one of the most difficult and expensive procedures in refrigerator repair. Unlike replacing a light bulb or a seal, this requires not just mechanical work, but also knowledge of how to work with refrigeration equipment.
The process involves bleeding out the old refrigerant, removing the faulty motor, installing a new one, evacuating the system to remove moisture and air, and then charging with the exact amount of freon. All this requires special tools: a burner, a vacuum pump, a pressure gauge station and scales.
In addition, modern refrigerants (for example, R600a) are explosive, which imposes additional safety requirements. Unprofessional replacement often leads to the fact that the refrigerator either does not freeze, or the new compressor quickly fails due to moisture or debris getting into the system.
⚠️ Attention: Replacing the compressor yourself without a license to work with freons and special equipment is prohibited and life-threatening. Entrust this work to certified specialists.
It is also worth considering that when the engine burns, acid and oil combustion products often remain in the system. Simply replacing the unit is not enough - you need to thoroughly flush the circuit with nitrogen and replace the filter-drier, otherwise the new motor will burn out in a few months.
How to extend the life of the compressor
In order for the “heart” of your refrigerator to beat evenly and for a long time, you must follow a number of simple operating rules. First of all, this concerns installation conditions. The refrigerator should be positioned at least 5-10 cm from the wall to ensure free circulation of air around the condenser.
Overheating is the main enemy of any electric motor. If the rear grille is clogged with dust, animal hair, or covered with furniture, heat transfer efficiency decreases, the motor overloads and wears out faster. Regular cleaning in this area is the best prevention.
- 🌡️ Temperature conditions: do not load hot foods into the chambers. This forces the compressor to work hard, trying to cool a large amount of heat.
- 🔌 Voltage stability: use surge protectors or voltage stabilizers, especially if electricity in your home often “jumps.”
- 🧊 Defrost mode: Even modern No Frost systems require periodic defrosting (once a year) to prevent the formation of ice jams in hard-to-reach places.
Following these recommendations will significantly increase the service life of the equipment. Remember that a high-quality compressor can work for decades if you create comfortable conditions for it.
The myth about two-compressor refrigerators
Many people believe that two compressors are always better. In fact, this only means independent cooling of the chambers. One powerful inverter compressor is often more efficient and quieter than two old linear ones.
Why does the compressor vibrate and hum a lot?
Vibration and hum can be caused by several reasons. First, check that the refrigerator is level on the floor. Adjusting the feet often solves the resonance problem. Secondly, vibration can be transmitted to the refrigerant pipes if they touch the housing or each other - in this case they must be carefully moved away. If the motor itself is humming and the sound is metallic, this is a sign of wear and tear on the internal mechanisms.
Is it possible to repair a burnt-out compressor?
At home, no. The sealed case is not intended to be opened. At specialized factories, there is a practice of overhauling and rewinding engines, but the cost of such work is often comparable to purchasing a new unit, and the reliability of the restored unit will be lower. Therefore, in 95% of cases, a complete replacement is recommended.
How much does it cost to replace a compressor?
The cost consists of the price of the unit itself (which depends on the power and brand, for example, Secop, Danfoss, LG) and the cost of the work of the technician. The price of the work includes travel, dismantling, soldering, vacuuming and refilling with freon. The total amount can be a significant part of the cost of a new refrigerator, so sometimes it is more advisable to buy new equipment.