The question of what metal the refrigerator motor is made of often arises among those who have encountered a breakdown of household appliances or are planning independent repairs. Understanding the materials used to manufacture a compressor is critical to assessing its repairability and longevity. Modern units are complex electromechanical devices, where each element is made of an alloy with certain physical properties.
The main mass of the compressor is steel parts, but the internal structure requires the use of non-ferrous metals to ensure conductivity and magnetic properties. It is the combination of ferromagnetic alloys and high quality conductors that makes it possible to create the pressure necessary for the circulation of the refrigerant. In this article we will analyze in detail the chemical composition of the main components.
Knowing what what metal is the refrigerator motor made of it is made will help you distinguish a high-quality unit from a cheap analogue when purchasing spare parts. In addition, this knowledge is necessary for the correct disposal of old equipment, since the cost of non-ferrous metals when scrapped differs significantly from the price of ferrous scrap metal. Let's dive into the technical anatomy of the “heart” of your refrigerator.
Main materials of the housing and external structure
The external part of the compressor, which is often called the “pot” or casing, is made primarily of sheet steel. This choice is due to the need to withstand high internal pressure, which can reach several atmospheres depending on the type of refrigerant. Steel provides the required strength tightness, preventing the leakage of freon and oil.
To protect against corrosion, the steel body is coated with special enamels or varnishes. However, if you plan to scrap the device, it is important to understand that it is ferrous metal that is hidden under the paint. The weight of such a casing constitutes a significant part of the mass of the entire unit, which makes it a convenient reference point for the initial inspection.
Fastening elements, such as bolts and studs, are also made of steel, often zinc-plated to increase anti-corrosion resistance. In some modern models, to reduce weight and vibration levels, composite materials can be used at the attachment points, but the supporting frame itself remains metal.
- 🔩 The main body of the casing is cold-rolled steel 1.5–2 mm thick.
- 🛡️ Protective coating is heat-resistant enamel or powder paint.
- ⚙️ The fastening paws are stamped steel with anti-corrosion treatment.
⚠️ Attention: Never try to open the steel compressor casing yourself if you do not have special equipment for subsequent sealed welding. Violation of the integrity of the housing makes further operation impossible.
Electric motor core: magnetic properties
Inside the steel casing there is an electric motor that drives the piston group. The heart of this motor is the stator and rotor, which are made of thin plates of electrical steel. This material has special magnetic propertiesthat minimize energy losses due to eddy currents.
The use of electrical steel with the addition of silicon allows to reduce engine heating during operation. The plates are insulated from each other with a special varnish, which prevents short circuits between the metal layers. If the core were solid, the efficiency of the engine would drop significantly, and overheating would become critical.
When disassembling a burnt out motor, you will notice that the plates have a characteristic grayish tint and are easily separated. This is the very metal that creates the magnetic field that rotates the rotor. The quality of this steel directly affects the energy consumption of the refrigerator.
It is important to note that electrical steel it differs from conventional structural steel in having lower magnetic permeability in the opposite direction, which is required for operation in AC networks. This is a high-tech material, the cost of which is higher than that of conventional rolled steel.
Why plates and not a monolith?
Using a set of plates instead of a solid piece of metal is necessary to break the paths of eddy currents. If the core were monolithic, huge Foucault currents would be induced in it, causing severe heating and loss of energy.
Windings: copper or aluminum?
The most important question for a repairman: what metal are the windings of a refrigerator motor made of? Traditionally and of the highest quality - this is copper. Copper wires have excellent electrical conductivity and can withstand significant temperature loads. However, in recent years, manufacturers of budget equipment are increasingly using aluminum.
Aluminum windings are cheaper to produce, but they are less durable. Aluminum has lower electrical conductivity, so to obtain the same power, the cross-section of the wire must be increased or put up with more heat. In addition, aluminum is more fragile and susceptible to oxidation at contact points.
How to determine the metal of the winding without disassembling it? Copper has a characteristic reddish-red color when broken, while aluminum is silvery-white. If you see the contacts inside the terminal box, try carefully scraping off the insulation (after de-energizing the device!).
- 🔸 Copper: high conductivity, ductility, oxidation resistance, expensive material.
- 🔸 Aluminum: low cost, light weight, prone to brittleness, requires special measures when handling soldering.
- 🔸 Copper-plated aluminum: a compromise option where the surface of the aluminum is covered with a thin layer of copper.
⚠️ Attention: When soldering aluminum windings with conventional solder, the connection will quickly collapse due to electrochemical corrosion. Special fluxes and solders are required for aluminum.
Internal mechanics: shaft, piston and connecting rod
The rotational movement of the rotor is transmitted to the crankshaft, which causes the piston to move. These parts experience enormous mechanical loads and friction. Therefore, they are made of high-strength alloy steels. Steel with the addition of chromium or molybdenum is often used to increase hardness.
The piston and cylinder must have a perfectly smooth surface to ensure tight compression. The metal here is selected with a minimum coefficient of thermal expansion so that the gaps remain stable when heated. In some models, the pistons can be made of special cast iron or composites, but the shaft is always steel.
The connecting rod connecting the shaft and the piston is also made of durable steel. In inverter compressors, the requirements for metal quality are even higher, since the shaft rotation speed can change dynamically, creating variable tensile and compression loads.
The table below shows a comparison of the main materials of internal parts:
| Part | Main material | Properties |
|---|---|---|
| Crankshaft | Alloy steel | High bending strength |
| Piston | Cast iron / Steel | Wear resistance, heat resistance |
| Bearings | Bronze / Steel | Low coefficient of friction |
| Valve plates | Elastic steel | High cyclic strength |
Valve group and tubes
The valve system is responsible for the direction of refrigerant flows. Valve petals are made of special spring steel, which can withstand millions of compression and expansion cycles without loss of elasticity. Refrigerator motor metal in this part it must be resistant to shock loads.
The tubes coming out of the compressor (discharge and suction) are usually made of steel, since they are a continuation of the body. However, some parts of the system adjacent to the compressor may use copper for ease of soldering and flexibility. It is important not to confuse materials when replacing pipes.
Steel adapters are often used at the joints of the tubes. The tightness of the connections is ensured by precise adjustment of metal surfaces and the use of solder. Oxidation of metal in these areas is unacceptable, so nitrogen purge is used during repairs.
If you notice that the tube at the base of the compressor has begun to rust, this is a signal that the protective coating has been broken. In conditions of high humidity and vibration, corrosion can lead to a through hole and leakage of freon.
Diagnostics of faults by the appearance of the metal
An experienced technician can tell a lot about the condition of the compressor simply by examining its external metal parts. If the steel casing has traces of deep corrosion, especially at the seams, this may indicate long-term operation in conditions of high humidity or overheating.
Darkening of the metal in the upper part of the “pot” often indicates that the motor was operating at critical temperatures. This could happen due to a lack of freon, which cools the windings, or due to problems with ventilation. Overheating detrimental to the varnish insulation of the windings.
The presence of oil smudges on the metal of the compressor is a sure sign of depressurization of the seals or cracks in body. The oil, flowing out, takes the lubricant with it, and the rubbing parts begin to deteriorate at a catastrophic speed.
- 🔍 Uniform color is a sign of normal operation.
- 🔍 Local carbon spots are a sign of overheating or short circuit.
- 🔍 Swelling of the metal is a sign of a critical increase in pressure inside.
☑️ Visual inspection of the compressor
Recycling and value of metal
When the refrigerator finally fails, the question of disposal arises. Compressor (compressor) is one of the most valuable parts in terms of non-ferrous and ferrous metal scrap. It weighs a lot, usually from 8 to 12 kg depending on the model.
When scrapped, compressors are often treated as an “electric motor” or disassembled separately. If there is a copper winding inside, the value of such metal is higher. However, in order to remove the copper, you need to saw the body, which is difficult to do at home due to the thick walls of the steel.
The average yield of non-ferrous metal (copper + aluminum) from one compressor is from 0.5 to 1.2 kg, the rest is black steel. Therefore, handing over entire compressors is often more profitable than trying to extract copper using a handicraft method, wasting time and resources.
Do not forget that compressor oil remains inside the compressor, which is a hazardous waste. waste). When disposing of the oil, it is necessary to drain the oil into a special container, and not pour it on the ground or down the drain.
Is it possible to rewind the refrigerator motor yourself?
Theoretically, this is possible, but in practice it requires complex equipment for winding coils and impregnating them with varnish under a vacuum. At home, it is almost impossible to rewind a compressor efficiently; it is easier and cheaper to buy a new one.
Why does the motor hum if the metal is intact?
The hum can occur due to unbalance of the rotating parts, wear of the bearings, or loosening of the fastening bolts of the compressor itself to the refrigerator frame. Metal has nothing to do with it, it’s a matter of mechanics.
Does the metal of the winding affect the noise?
The winding material (copper or aluminum) does not have a direct effect on the noise level. Noise is created by mechanical components: piston, valves and body vibration. However, aluminum motors can run hotter, which indirectly affects the sound of expanding metal.