What is inside the refrigerator motor: device, types and principle of operation

When the refrigerator suddenly stops freezing or starts to hum loudly, the first thought is that there is a problem with the motor. But what exactly is hidden under the metal body of this unit? Why do some compressors last for decades, while others fail after a couple of years? In this article we will analyze in detail the design of a refrigerator motor, open its “inner world” and explain how each element affects the operation of the equipment.

You will be surprised, but a modern compressor is not just a “pump for freon”. This is a complex system with valves, windings, oil passages and even electronic sensors in advanced models. We will show how linear, inverter and piston motors differ, why some of them operate almost silently, while others emit a characteristic “rumbling”. You will also learn what breakdowns you can diagnose yourself, and when it is better to call a specialist.

Important: if you plan to disassemble the refrigerator motor with your own hands, remember - this Dangerous due to high refrigerant pressure and the risk of electric shock. Even when the compressor is disconnected from the mains, there may be residual charge in the capacitors. All procedures described below are for informational purposes!

Main components of the refrigerator motor: disassembling the “stuffing”

The heart of the refrigerator - the compressor - consists of several key components, each of which performs its own function. Let's look at them in order, from the outer case to the internal mechanisms.

Let's start with sealed housing a steel cylinder that protects internal parts from dust, moisture and mechanical damage. Inside it is:

• 🔧 Electric motor - creates rotational motion, which is converted into translational movement of the piston (in piston models) or linear movement (in inverter models).
• 🛢️ Oil pump - provides lubrication of rubbing parts parts. Most models use a special compressor oil that is compatible with the refrigerant.
• 🔄 Valve system —inlet and outlet valves that regulate the flow of refrigerant. Their serviceability directly affects the pressure in the system.
• 🧲 Start relay - located outside the housing, but is closely connected with the operation of the motor. Responsible for starting the windings and protecting against overloads.

Deserves special attention refrigerant (most often R134a or R600a in modern models). It circulates in a closed loop, changing its state of aggregation from gaseous to liquid and back. It is this process that ensures the cooling of the chambers. It is interesting that old Soviet refrigerators (ZIL, "Minsk", "Biryusa") used freon R12, which today is prohibited due to harm to the ozone layer.

Inside the case there is also thermal protection relay a small device that turns off the motor when it overheats. It is triggered if the temperature of the windings exceeds 120-140°C (the exact values ​​depend on the model). This prevents insulation melting and short circuits. By the way, it is precisely because the thermal protection is triggered that the refrigerator can “rest” for 10-15 minutes after long-term operation - this is normal!

Types of motors: piston, inverter and linear

Not all compressors are the same. Their design and operating principle can differ radically depending on the technology. Let's look at the three main types that are found in household refrigerators.

1. Piston (classic) compressors

This is the most common and time-tested type. The operating principle is similar to an internal combustion engine: a piston moves inside the cylinder, compressing the coolant. Main features:

• ⚡ High starting current (up to 10-12 A), which can create a load on the network.
• 🔊 Noise level: 40-50 dB (you can hear a “rumbling” when work).
• ⏳ Resource: 10-15 years with proper use.
• 💰 Price: the most budget option, therefore it is installed in refrigerators economy class (ATLANT, Indesit, Beko).

2. Inverter compressors

Technology borrowed from air conditioners. There are no sudden on/off switches - the motor smoothly regulates power depending on the temperature in the chamber. Advantages:

• 🔇 Noise level: 30-35 dB (almost silent).
• ⚡ Energy savings up to 30% due to the absence of peak loads.
• ⏳ Resource: 15-20 years (less wear due to smooth starting).
• 💰 Price: more expensive than piston ones 20-40%, installed in premium models (LG, Samsung, Bosch).

3. Linear compressors

The most modern development (used, for example, in refrigerators LG Linear Inverter). Here the piston moves not in a circle, but in a straight line, which reduces friction and increases efficiency. Characteristics:

• 🔋 Energy consumption by 50% lower than piston ones.
• 🔇 Noise: 25-30 dB (quieter than inverter ones).
• ⚡ Minimum starting currents.
• 💰 They are the most expensive in production, so they are found only in top models.

Which type is better? There is no definite answer - it all depends on the budget and requirements For a summer house or. A reliable piston compressor is suitable for a garage, but for a studio apartment it is better to choose an inverter or linear one. The main thing is to remember: If your network has unstable power, be sure to use a stabilizer! process inverter motors do not like frequent power surges. If your network has unstable power supply, be sure to use a stabilizer!

How does a refrigerator motor work: step by step process

Now let's figure out how exactly the compressor provides cold in the chambers. The entire cycle can be divided into 4 stages:

1. Starting and sucking in the refrigerant

When the thermostat detects an increase in the temperature in the chamber, it sends a signal to the start relay. closes the circuit, and the electric motor begins to rotate. At this moment, a vacuum is created in the cylinder, and gaseous refrigerant is sucked in from the evaporator (the same “grid” on the back wall of the refrigerator). intake valve gaseous refrigerant is sucked in from the evaporator (the same “grid” on the back wall of the refrigerator).

2. refrigerant

The piston moves upward, compressing the refrigerant to pressure 10-15 atm. At the same time, its temperature rises sharply (up to 70-90°C). It is important here that the valves are tight - if they leak, the compressor will run “idle” without creating the required pressure.

3. Discharge into the condenser

The compressed and heated refrigerant through exhaust valve enters the condenser (the same “coil” tube on the back wall of the refrigerator) Here it is cooled, giving off heat to the environment. environment, and turns into a liquid state. By the way, if the condenser is clogged with dust, heat transfer deteriorates and the motor begins to work with overload!

4.

Liquid refrigerant passes through capillary tube (or thermostatic valve in modern models), where its pressure drops sharply. Once it enters the evaporator, it boils, absorbing heat from the chamber. The cycle is repeated until the temperature reaches the set value.

Why is the refrigerator motor hot?

This is normal! The temperature of the compressor housing can reach 60-80°C. Heating occurs due to compression of the refrigerant and friction of parts. The only danger is if the motor burns when touched (above 90°C) or the thermal protection switches off.

Interesting fact: in refrigerators with a system No Frost the cycle is a little more complicated. There is an additional fanhere, which evenly distributes cold air throughout the chambers, and heating element for defrosting. This increases the load on the compressor, so such models are usually equipped with more powerful motors.

Common motor failures and their symptoms

The compressor is the most reliable unit refrigerator, but it can also fail. Let's look at typical faults and their symptoms. If you notice anything from this list, the motor may require diagnostics.

One of the most insidious failures is turn-to-turn short circuit in the windings. It is difficult to diagnose without special equipment (megaohmmeter), but it can be suspected based on the following signs:

• 🔌 The motor starts, but after a few seconds it turns off with a characteristic click (the starting relay is activated).
• 🔥 The compressor housing heats up more than usual.
• 💡 The light inside the refrigerator blinks or dims when starting.

Another common problem is refrigerant leak. It can be recognized by the following signs:

• ❄️ The refrigerator does not turn off, but the temperature in the chambers does not drop below +10...+15°C.
• 🧊 There is no frost on the back wall (in models with a drip system).
• 🔧 The condenser (grid at the back) remains cold even after an hour of operation.

⚠️ Attention! If you suspect a freon leak, under no circumstances try to “top up” the system yourself. The refrigerant R600a (isobutane) used in modern refrigerators is extremely explosive if leaked in a closed room. Contact a technician with a license to work with refrigerants.

How to check the refrigerator motor yourself

Before calling a technician, you can carry out preliminary diagnostics. You will need:

• 🔧 Screwdriver (to access the compressor).
• 📊 Multimeter (to check the windings).
• 👓 Safety glasses (in case the system depressurizes).

Step 1. External inspection

Unplug the refrigerator and carefully move it away from the wall. Inspect the compressor (black “barrel” at the bottom):

Step 2. Checking the windings with a multimeter

Remove starting relay (usually secured with latches or one bolt). You will see three winding outputs: C (common), S (starting), R (working). Measure the resistance:

• Between C and S: it should be 20-40 Ohm (start winding).
• Between C and R: there should be 10-20 Ohm (working winding).
• Between S i R: should be 30-60 Ohm (sum of resistance).

If the resistance is equal 0 (short circuit) or ∞ (break), the motor is faulty.

Step 3. Check for current leakage

Turn the multimeter into resistance testing mode to the maximum limit (2000k or 20 MOhm). Measure the resistance between any winding terminal and the compressor housing. If it is less 1 MOhm, there is a breakdown in the housing - the motor must be replaced.

⚠️ Attention! If you have never worked with electricity, have a professional check the windings. An error in measurements can lead to electric shock even when the compressor is turned off (due to residual charge in the capacitors).

When the motor needs to be repaired, and when - only replaced

Not all compressor breakdowns are fatal. In some cases, you can get by with repairs, in others - only replacement. Here are the main criteria:

Can be repaired:

• 🔧 Faulty start relay (replacement in 15-20 minutes).
• 🛢️ Clogged capillary tube (rinsing system).
• 🔌 Breakage of the power wire or oxidation of the contacts.
• 🧲 Malfunction of the thermal protection relay (replacement of a separate element).

Motor replacement required:

• 🔥 Interturn short circuit or breakage of the windings.
• 💥 Breakdown on the housing (dangerous to life!).
• 🔧 Wear of the piston group (knocks, low pressure).
• 🛢️ Oil leakage from the housing (visible by oil stains).

The cost of a new compressor depends on the refrigerator model:

• 💰 For budget models (ATLANT, Indesit): 5 000–8 000 ₽.
• 💰 For the middle class (Samsung, LG): 8 000–15 000 ₽.
• 💰 For premium models (Liebherr, Bosch): 15 000–25 000 ₽.

It is important to consider that replacing a compressor is only 50% the cost of repairs. You will also need:

• 🛠️ Refilling with refrigerant (1 500–3 000 ₽).
• 🔧 Replacing the filter drier (500–1 000 ₽).
• 👨‍🔧 The work of a master (3 000–6 000 ₽).

An exception is refrigerators with inverter motors. Their compressors rarely fail, but if this happens, replacement will cost expensive (up to 70% the cost of new equipment). In this case, it makes sense to consider buying a new refrigerator with a guarantee.

Tips for extending the life of the refrigerator motor

Even the most reliable compressor can be “ruined” in a couple of years if you do not follow simple operating rules:

1. Correct placement

• 🌡️ Do not place the refrigerator near the stove, radiator or in the sun. Optimal temperature around - 16–32°C.
• 🔌 Ensure free access of air to the condenser (rear grill) - 5 cm.
• ⚡ Connect the refrigerator to a grounded outlet. Voltage surges are the main reason for the windings to burn out.

2. Regular maintenance

• 🧹 Clean the condenser from dust every six months (you can use a vacuum cleaner or soft brush).
• 🧊 Defrost the refrigerator at least once a year (even if you have No Frost).
• 🔧 Check the door seals - if they are worn out, the motor is overloaded.

3. Careful operation

• ❄️ Do not put hot food in the refrigerator - this causes a sharp jump in the load on the compressor.
• 🚪 Do not keep the door open longer 30 seconds.. Every minute with the door open increases the operating time of the motor by 5–10 minutes.
• 🔌 Do not unplug the refrigerator for a long time (more than a day). This may cause the oil in the compressor to dry out.

For refrigerators with inverter motors there are additional recommendations:

• ⚡ Use a voltage stabilizer if there are frequent surges in your network.
• 🔇 Do not place the refrigerator close to the walls - vibration from an inverter compressor may increase the noise.
• 🌡️ Avoid sudden changes in room temperature (for example, if the refrigerator is on an unheated balcony).

⚠️ Attention! If your refrigerator suddenly becomes loud after moving or transporting, do not panic. The oil in the compressor may have mixed with the refrigerant. Let the appliance stand 6–12 hours before turning it on - usually the noise disappears.

FAQ: Frequently asked questions about the refrigerator motor

Why does the refrigerator motor work without stops?

There are several reasons:

• 🌡️ The temperature is set incorrectly (value is too low).
• 🔧 Thermostat is faulty (does not give a shutdown command).
• 🧊 Refrigerant leak (the motor is trying to compensate for the lack of cold).
• 🛢️ The condenser is dirty (poor heat transfer).
• 🚪 The door seal is worn out (constant influx of warm air).

Check simple things first: close the door tightly, clean the condenser, set the temperature to +4...+5°C. If it doesn’t help, call a specialist.

Is it possible to replace a piston compressor with an inverter one?

Technically possible, but impractical. Here's why:

• 💰 The cost of an inverter motor is 2-3 times higher than a piston motor.
• 🔧 The starting motor will need to be replaced relay and, possibly, an electronic control unit.
• ⚡ Not all refrigerators are designed for smooth power control.

In most cases, it is cheaper to buy a new refrigerator with an inverter compressor than to upgrade an old one.

What refrigerant is used in modern refrigerators?

90% of models after 2010 use:

• R600a (isobutane) - environmentally friendly, but explosive if leaked. Used in household refrigerators (ATLANT, LG, Samsung).
• R134a - less effective, but safe. More often found in commercial refrigerators.

In older models (before the 2000s) freon was used, which is now prohibited. R12 (freon), which is prohibited today.

⚠️ Attention! Refrigerant R600a is not compatible with all types of oils. When refilling, be sure to use polyester oil (POE), otherwise the compressor will quickly fail.

Why does the new refrigerator get very hot at the back?

This is normal! Heating of the condenser (rear grill) is an integral part of the operation of the refrigerator. The temperature here can reach 50–70°CDangerous signs that indicate a malfunction:

• 🔥 Housing the compressor (not the capacitor!) heats up above 90°C.
• 🕒 The heating does not decrease even after 1–2 hours work.
• 💨 Hot air blows from under the refrigerator (may indicate a fan malfunction in the models No Frost).

If none of this is present, do not worry, your refrigerator is working correctly.

How long should the refrigerator motor run?

The ratio of work and rest depends on:

• 🌡️ Room temperatures.
• 🧊 Chamber load.
• 🔧 Compressor type.

Normal values:

• 🕒 Piston compressor: running 10–15 minutes, resting 20–30 minutes.
• 🕒 Inverter compressor: running almost continuously, but at reduced power.

If the motor runs longer 40 minutes without stopping - this is a reason for diagnosis.