Many owners of old household appliances often think about where to put a broken refrigerator. However, throwing it away entirely is not the most rational decision, especially if the heart of the unit compressoris still working. This powerful electric motor has unique characteristics that allow it to create high pressure and operate autonomously. Using it as a basis for new devices is a great way to save budget and show engineering ingenuity.
The range of applications for such a motor is incredibly wide: from simple pumps for inflating tires to complex aeration systems in aquariums or even homemade spray guns. The main thing is to understand the principle of operation sealed unit and follow safety precautions when remodeling. In this article, we will look at how to properly remove the unit, connect it, and what interesting projects can be implemented with a minimum of tools on hand.
Before you begin assembly, it is important to realize that a refrigerator compressor is not an ordinary fan. It works in a closed circuit with freon and special oil. When working in atmospheric air, oil can be carried away along with the flow, which requires the installation of an oil trap to ensure the purity of the exhaust gas. Proper preparation of the equipment is the key to the durability of your future homemade product.
Design features and principle of operation
A refrigeration compressor is piston unitenclosed in a sealed metal casing. Inside there is an electric motor that drives the crank mechanism. Unlike open compressors, there are no oil seals, and all rubbing parts operate in an oil bath, which ensures low noise levels and a long service life.
The housing usually has three terminals for connecting to the electrical network. These are the starting and working windings, as well as the common wire. To start the engine, starting relayis used, which automatically turns off the starting winding after gaining speed. Without this element, it will not be possible to start the motor, since it will only hum and not rotate.
⚠️ Attention: Never open the sealed compressor casing. There may be gas under pressure inside, and damage to the integrity of the housing will make the unit unsuitable for further use as a compressor.
An important feature is the presence of two pipes: suction and discharge. They can be determined experimentally by briefly applying power. The one that blows is a discharge, the one that sucks in air is a suction. It is on the discharge pipe that hoses for supplying air to the tool will be subsequently mounted.
Oil inside the compressor
The oil located inside the compressor is mineral and not hygroscopic. It does not require frequent replacement, but during prolonged operation in air it can oxidize, so once a year it is recommended to check its level through the drainage hole (if it is provided for in the design) or simply monitor the absence of vibrations.
Necessary tools and materials
To create a full-fledged compressor installation, you will need not only the motor itself. The basis will be a receiver - a container for storing compressed air. This can be an old fire extinguisher, a gas cylinder, or even a durable plastic canister if the pressure is planned to be low. Receiver necessary to equalize pressure pulsations and ensure smooth air flow.
You will also need accessories for pneumatics: a check valve that will prevent air from escaping back to the compressor when it stops, and a pressure switch (pressostat). The pressure switch will automatically turn off the engine when the pressure in the receiver reaches a predetermined maximum, and turn it on again when it drops. Without this element, the system will work constantly, which will lead to overheating.
- 🛠️ Tools: drill, set of drills, screwdrivers, pliers, wire cutters.
- 🔩 Consumables: clamps, hoses (oil-resistant), adapters, fittings.
- ⚡ Electrics: wire with plug, electrical tape or heat shrink, circuit breaker.
- 🧪 Additional: pressure control gauge, moisture separator.
All connections must be sealed. To seal threaded connections, use fum tape or anaerobic sealant. Do not skimp on the quality of hoses, as low-quality rubber can burst under pressure, causing injury.
Step-by-step instructions for assembling the compressor
The assembly process begins with preparing the receiver. If you use a fire extinguisher, make sure it is empty and free of corrosion. Drill holes in the top for air outlet, installation of a pressure gauge and pressure switch. All holes must be thoroughly cleaned of metal shavings.
Next is the installation of the compressor on the base. To do this, it is best to use a wooden board or metal sheet, to which the motor is attached through rubber gaskets. Vibration during operation is inevitable, and rigid fastening will lead to rapid destruction of the structure and increased noise. You can place automobile silent blocks under the legs of the compressor.
Connection diagram:220V network -> Pressure switch -> Compressor start relay
Pressure switch -> Compressor (start/stop)
Pressure switch -> Signal lamp (optional)
Connect the compressor to the receiver through a check valve. The valve is installed immediately after the engine discharge pipe. This is a critical element: it prevents air backlash that could strip oil or damage the piston group when the engine stops. After the valve, a tee is installed for the pressure gauge and pressure switch.
☑️ Check before first start
Table of characteristics of a homemade compressor
Understanding the technical limitations will help you choose the right tool for the job. A standard refrigerator compressor is not designed to create high pressure, like its industrial counterparts, but it is quite sufficient for domestic needs. Below are approximate parameters that you can count on.
| Parameter | Value | Note |
|---|---|---|
| Working pressure | up to 6-8 atm | Depends on the motor model |
| Performance | 50-100 l/min | Input, less output |
| Power consumption | 100-200 W | Economical consumption |
| Operating mode | 50% (PV) | Needs rest |
| Noise level | 40-50 dB | Relatively quiet |
As can be seen from the table, such a unit is ideal for working with an airbrush, inflating tires or blowing electronics. However, to work with pneumatic tools that require a large volume of air (for example, a wrench), one motor will not be enough. In such cases, a pair of two or three compressors is assembled.
Top 5 ideas for using a compressor
After assembling the main installation, many possibilities open up before you. Firstly, this airbrush. A pressure of 2-3 atmospheres is ideal for applying paint to models, nails or car body. Fine adjustment of the flow allows you to create complex gradients.
Secondly, the compressor is indispensable for cleaning the computer and other electronics from dust. A jet of air under pressure blows contaminants out of hard-to-reach places better than any canister that runs out quickly. Thirdly, this is inflating the tires of a bicycle, car or boat.
- 🎨 Airbrush: Drawing pictures, priming small parts.
- 🔧 Pneumatic tools: Working with mini-drills, grinders (requires a large receiver).
- 🐠 Aeration: Oxygen saturation of water in an aquarium or pond.
- 🧹 Purge: Cleaning filters, radiators, keyboards.
You can also make a vacuum pump based on the compressor. To do this, you simply need to reverse the hose connection diagram: take air from the container and release it into the atmosphere. This is useful for vacuum packaging of products or molding of plastic parts.
⚠️ Attention: When using a compressor for airbrushing or painting, be sure to install a high-quality moisture-oil separator. If oil gets on the surface to be painted, it will spoil the result and require complete repainting.
Safety precautions and maintenance
Operation of homemade equipment requires strict adherence to safety rules. The compressor heats up during operation, so do not cover it and ensure good ventilation. Overheating can lead to melting of wire insulation or even ignition of oil upon contact with air.
Regularly check the oil level (if the design allows) and the condition of the air filters. A clogged inlet filter causes the motor to overload, which shortens its service life. Once every six months, it is recommended to drain the condensate from the receiver by opening the bottom tap, since moisture causes corrosion of the metal from the inside.
If you notice that the motor has become louder, vibrates more strongly or does not build up pressure for a long time, stop using it and carry out diagnostics. Perhaps the rings or valves are worn out. Timely repair will cost less than buying a new unit.
Frequently asked questions (FAQ)
Is it possible to use a compressor from a Soviet refrigerator?
Yes, old compressors (for example, the XK series) are considered more reliable and powerful than modern ones. They are able to develop greater pressure and have thicker casing walls, which reduces noise. However, they may consume more electricity.
What kind of oil should be poured into the compressor?
In hermetic compressors, oil is filled at the factory and usually does not require replacement. If the level has dropped, you need to add special compressor oil (for example, FKS or analogues), and not engine oil or waste oil. Ordinary oil can foam and coke.
Why does the compressor hum, but does not start?
Most likely, the start relay is faulty or the piston is jammed. Try gently tapping the body with a rubber mallet. If it doesn’t help, check the relay; the starting winding may have burned out or the contacts have oxidized.
What is the maximum size of the receiver?
The size of the receiver is limited only by the performance of the compressor. If you take a cylinder that is too large, the motor will take a very long time to pump it up to operating pressure. Optimally - 50-100 liters for one motor.
Is it necessary to change freon to air?
Freon in the compressor acts as a refrigerant in the refrigerator system, and not as a lubricant. When converting to air, the freon is simply released, since it is not needed in the new system. The oil remains inside to lubricate the rubbing parts.