Legends still walk on the Internet about what welding machine can be assembled from an old compressor from a refrigerator. Enthusiasts are looking for ways to turn discarded appliances into powerful metal-joining tools, believing the electric motor can generate an arc. However, if you understand the physics of the process and the design of the unit, it becomes obvious: this idea is technically impracticable and dangerous.
The refrigerator compressor is a sealed pump that works to compress freon, and not a source of welding current. Trying to use it for welding is not only a waste of time, but also a recipe for cylinder or electric shock. In this article, we will look in detail at why this idea is doomed to failure, and what can actually be done with this unit. explosion cylinder or electric shock. In this article, we'll take a closer look at why this idea is doomed to fail, and what can actually be done with this node.
Electric motorlocated inside the compressor can indeed be used for other purposes, but only after complete disassembly and removal from the sealed housing. The assembly itself, in the form of a “pan” with protruding tubes, is absolutely useless for creating a welding arc. Let's look at the technical details.
Physical principle of operation of welding and compressor
To create an electric arc that melts metal, you need a source of direct or alternating current with very low voltage levels, but enormous current. Welding inverter converts 220V mains voltage into a current of 60-200 Amps at a voltage of only 20-30 Volts. This is a fundamentally different mode of operation than that of household appliances.
The refrigerator compressor, be it Atlant, Donbass or LG, is equipped with a single-phase asynchronous motor. Its task is to rotate the shaft on which the pistons or spiral are attached. It consumes current from the network, creating a magnetic field in the stator windings, but does not generate welding current. The maximum current consumption of such a motor is 1-2 Amperes, which is 100 times less than that required for welding minimum.
An attempt to connect the electrodes directly to the motor terminals will only lead to a short circuit and burning of the wiring. The motor is not a transformer and cannot change the network parameters as required. Moreover, the internal winding is made of thin wire, designed for a specific load, and will instantly melt when trying to force the current.
There is a misconception that if you spin the motor shaft with an external force, it will become a generator. Even if this is successful, you will get an unstable voltage at the output, unsuitable for welding. To maintain an arc, a rigid current-voltage characteristic is needed, which a mechanical generator cannot provide without sophisticated electronics.
⚠️ Attention: Opening the sealed compressor housing ("pan") with an angle grinder is strictly prohibited without observing safety measures. There may be compressed gas or oil vapor inside, which, upon contact with a spark, will cause a powerful bang.
Design limitations of the refrigeration unit
Looking at the design of the compressor, we see that it is a sealed steel casing. Inside there is itself electric motor, a cylinder-piston group and a valve system immersed in oil. Access to the stator and rotor windings is possible only after the housing is destroyed, which turns the product into a pile of metal and not into a functional unit.
Even if you remove the motor, you will face the problem of its fastening and cooling. In normal mode, the motor is cooled by freon vapor and oil circulating inside the system. In the open air under high loads, it will overheat in a few minutes. Thermal protection, built into the starting relay, will constantly turn off the power.
The dimensions and weight of the compressor are also not conducive to creating a mobile welding machine. The weight of an average unit is 8-12 kg, and this is “dead” weight, since most of it is steel and oil. For comparison, modern welding inverters weigh 2-3 kg and fit in a backpack.
Why can’t you use a compressor as a transformer?
Many people confuse an engine with a transformer. The motor converts electrical energy into mechanical energy (rotation). The transformer changes the current parameters (voltage and strength). The design of the core and windings is different. An attempt to rewind the motor stator under a welding transformer is theoretically possible, but it is labor-intensive and requires deep knowledge of electrical engineering; it is easier to buy a ready-made transformer from a microwave.
Why the idea of a “generator from a motor” is wrong
The idea that a motor can be used as a generator often appears in requests. Yes, an asynchronous motor can operate as a generator if its shaft is spun above synchronous speed and the windings are powered with capacitors to create a magnetic field. However, the power of such a generator will be equal to the power of the engine, that is, 100-200 watts.
For welding even thin metal (1 mm), a power of at least 2-3 kW is required. Thus, the motor from the refrigerator will simply “choke.” The arc either will not ignite or will instantly go out at the slightest movement of the electrode. Inductance The windings will not allow a sharp jump in current required to break down the air gap.
In addition, the shaft rotation speed must be strictly constant. Any change in the load on the arc will lead to voltage surges. It is impossible to weld something of high quality with such a “device”. The seam will be porous, without penetration, and the electrode will constantly stick.
The table below shows a comparison of parameters demonstrating the incompatibility of these devices:
| Parameter | Refrigeration compressor | Welding inverter |
|---|---|---|
| Power consumption | 100-200 W | 2000-5000 W |
| Output current | Not applicable (mechanics) | 20-200 A |
| Arc voltage | - | 20-30 V |
| Device weight | 10 kg | 2.5 kg |
Real use of compressor parts
Although this unit will not turn into a welding machine, its individual components find excellent use in the household. The most valuable part is pump (pump part). After dismantling and cleaning, it is ideal for creating an airbrush, a compressor for an aquarium, or inflating tires.
Copper from the windings of a burnt engine is a non-ferrous metal that is accepted at recycling points. From one motor you can extract up to 500-700 grams of pure copper. This is perhaps the most rational use of a faulty unit.
The compressor housing, if carefully opened, can be used as a sealed container for storing liquids or gases under low pressure, although this requires serious skills in working with metal. Start relay radio amateurs are often used as a source of powerful contacts or magnets.
When converting a compressor for painting, you definitely need a high-quality filtration and moisture separation system, otherwise the paint will show defects.
Safety precautions during disassembly
If you decide to disassemble the compressor to obtain copper or parts, use extreme caution. The housing is filled with oil, which may ignite if heated or sparked. Work in a well-ventilated area, away from open flames.
Use safety glasses and gloves. When sawing the body with a grinder, metal shavings are formed, which can get into the eyes. Also, the sharp edges of sawn metal easily cut the skin. Electrical safety When checking the windings, it is also important: use a multimeter and do not connect the motor to the network without checking the insulation.
⚠️ Attention: Never attempt to start a disassembled or partially disassembled compressor. Lack of oil cooling and freon circulation will lead to instant overheating and fire of the windings.
Dispose of residues correctly. The freon contained in the system is harmful to the ozone layer. Although the amount of it in older models is small, it is not recommended to release it into the atmosphere. It is better to hand over the entire unit to a specialized collection point.
Alternative ways to obtain a welding machine
If your goal is to obtain a welding machine with your own hands, use proven methods. The most affordable option is conversion transformer from a microwave oven (microwave). Its high-voltage winding is cut off, and in its place a new one is wound from a thick wire (3-4 turns).
You can also assemble a simple inverter based on powerful transistors or buy a ready-made budget device. Modern Chinese models are inexpensive, compact and safe to use. They are equipped with protection against electrode sticking and overheating.
Homemade welding from a microwave transformer allows you to weld metal up to 3-4 mm thick with a 3 mm electrode. This is quite enough for everyday needs: repairing a gate, cooking a barbecue or assembling a shelving unit. This is a really working circuit, unlike the mythical apparatus from a refrigerator.
☑️ What is needed for welding from a microwave transformer
Conclusion and conclusions
The idea of making a welding machine from The refrigerator engine is technically illiterate. The difference in operating principles, power and purpose of the devices makes this task impossible. Compressor created to compress gas, and not to generate an arc discharge.
Attempts to implement this project will only lead to property damage and the risk of injury. It is better to use the compressor for its intended purpose - as a pump, or sell it for scrap. For welding, use specialized equipment or proven transformer-based circuits.
Take care of yourself and do not believe dubious instructions from unverified sources. Safety should always come first when working with electricity and metal.
Is it possible to use copper from the engine to wind a welder?
Yes, copper from the windings can be used, but it will have to be melted down and drawn into wire of the required section, which is extremely difficult at home. It’s easier to buy ready-made copper wire.
Will the compressor burn out if you connect it to the welding current?
It will burn out instantly. The welding current is tens of times higher than the rated current of the motor. The windings will turn into a fuse link in a split second.
What is the minimum power required for a motor for homemade welding?
The motor cannot be a source of welding. For homemade welding, you need a transformer with a power of at least 1.5-2 kW, and not an electric motor.
Is it dangerous to open the compressor at home?
Yes, it is dangerous. There may be residual pressure inside, and oil and freon vapors are toxic and flammable. Open only in the open air in compliance with fire safety measures.