Dismantling and subsequent disassembly motor-compressor is a task faced not only by professional repairers of household appliances, but also by home craftsmen who want to sell an old unit for non-ferrous metal or restore a failed unit. An old refrigerator that has reached the end of its useful life often stops cooling food due to the breakdown of this particular expensive component. Understanding the design and sequence of actions is necessary for safe work.
It is important to immediately realize that disassembling the sealed compressor casing requires specific tools and precautions, since there may be compressed gas and technical oil inside. Sealed unit designed to work for decades without intervention from the outside, so opening it is an irreversible process, after which it will no longer be possible to assemble the compressor back to its factory version. However, for diagnosing internal breakdowns or disposal, this step is inevitable.
Before you begin physical impact on the metal, you must make sure that the refrigerant is completely removed from the system and the electrical part is de-energized. In this article, we will look at the stages of preparation, the necessary tools and a step-by-step algorithm of actions that will allow you to safely dismantle and disassemble the unit, minimizing risks to health and equipment.
Safety precautions and workplace preparation
Working with refrigeration components involves certain risks associated with both electricity and chemicals. Refrigerantcirculating in the system, even in older models, can be toxic or flammable, so any manipulations with pipelines should be carried out in a well-ventilated area or in the open air. Ignoring this rule can lead to poisoning or ignition of oil vapors mixed with gas.
Electrical safety also comes first, because the motor-compressor operates on a 220-volt network. Before starting any work, be sure to disconnect the power cord from the outlet and check that there is no voltage at the terminals. Start relay and the thermostat can retain charge in the capacitors, so it is a good idea to let the equipment stand unplugged for a while.
⚠️ Attention: Never try to cut through copper cooling system tubes without preliminary release of freon. A sharp pressure drop can spray technical oil, and a spark from a tool can ignite refrigerant vapors if it is a model running on isobutane.
For comfortable work, prepare a stable table or workbench covered with rags, since a significant amount of used oil will leak out of the compressor when opened. Take care in advance of a container for collecting technical fluids and the availability of personal protective equipment: gloves, goggles and a respirator. Safety glasses It is especially important when working with an angle grinder or a hacksaw so that metal shavings do not get into your eyes.
If you plan not just to dispose of, but to repair node, then the cleanliness of the workplace is critically important. If dust or moisture gets inside the mechanism during assembly, it can lead to immediate failure of new parts. Try to carry out work in a room with a minimum number of drafts that raise dust.
Required tools for dismantling
The quality and speed of work directly depend on how correctly the tool is selected. To remove the compressor from the frame of an old refrigerator and then disassemble it, you will need a set of both plumbing and, possibly, power tools. The basic set includes screwdrivers of various types, pliers and side cutters.
- 🛠️ A set of wrenches or sockets for unscrewing the frame mounting bolts.
- 🔪 A sharp knife or a special tool for stripping copper tubes.
- 🔨 A hammer and chisel (or a grinder with a metal disk) for opening the casing.
- 🧤 Thick work gloves to protect hands from sharp metal edges.
- 🧴 A container for draining used compressor oil.
Particular attention should be paid to the tool for working with copper pipes. If you plan to save the compressor for future use (for example, as a vacuum pump), then the tubes must be cut off carefully, leaving “stumps” of sufficient length. For this, it is best to use pipe cutter, which gives an even cut without burrs, unlike a hacksaw for metal.
If the goal is to disassemble the internal mechanism for study or scrapping, the integrity of the case does not need to be preserved. Here an angle grinder (grinder) with a thin disk will come to the rescue. It allows you to quickly and smoothly cut off the top cover of the casing along the weld seam. However, when working with power tools, you should be extremely careful not to damage the internal stator windings from sparks or overheating.
The process of removing the compressor from the refrigerator frame
The first stage is removing the unit itself from the refrigerator body. In old Soviet-made models and early imported samples, the compressor is usually located in the lower rear part, in a niche. Access to it is often limited by a metal casing or plastic cover that must be removed.
Once you gain access, you will see a black metal “barrel” with copper tubes and an electrical cable suitable for it. The first step is to disconnect the electrical part: remove the start relay cover and disconnect the wires from the terminals. It is recommended to take a picture of the connection diagram or sketch it before this, so that if the repair is successful, you will know where to connect what.
Next comes the turn of the copper tubes. They must be bitten off with wire cutters or sawed through with a hacksaw at a distance of 10-15 centimeters from the compressor housing. Plug the holes in the tubes with your fingers or plugs immediately after cutting, so that air and moisture, which are detrimental to the system, do not get inside. Having disconnected the communications, you can begin dismantling the fastening elements.
The compressor is attached to the refrigerator frame using 4 shock-absorbing bushings or bolts. Older models often have bolted connections that can become acidified due to time and moisture. Unscrewing them may require a penetrating lubricant (such as WD-40) and considerable physical force. Act carefully so as not to strip the threads and damage the frame.
☑️ Dismantling checklist
Opening the sealed motor casing
The most important and labor-intensive stage is opening the steel housing into which The electric motor and mechanical part are pressed in. The factory welding is done very well, so you can’t just open the lid. There are two main methods: a neat cut of the seam and a barbaric breakdown.
If you want to save the compressor for conversion, for example, into a compressor for airbrushing, then the seam needs to be cut in a circle with a grinder. This requires a steady hand and care: it is important not to damage the internal winding or deform the stator. The cutting depth is controlled visually, stopping at the moment when the disk begins to touch the internal cavity.
For recycling purposes or if appearance is not important, you can use a more crude method. Using a chisel and hammer, notches are made along the perimeter of the junction of the upper and lower bowls, after which the lid is knocked out. It is also common to simply saw through a “window” in the upper part of the casing. The main thing is not to damage stator windingif you plan to check it for interturn short circuit.
⚠️ Attention: There is always technical oil inside the casing. At the first cut or blow, it will begin to flow out. Place the container in advance and prepare a rag, since the oil has a specific smell and is difficult to wash off.
After removing the lid, the internal structure will open in front of you: a stator with copper windings, a rotor and the piston mechanism itself, immersed in oil. At this stage, it is already possible to carry out visual diagnostics: check for obvious signs of burning, melting of insulation or mechanical jamming of parts.
Diagnostics and design of internal mechanics
Inside the casing is hidden a complex system that converts electrical energy into piston movement. The basis is electric motor, the shaft of which is directly connected to the crank mechanism. During operation, the piston performs reciprocating movements, compressing the refrigerant and pushing it through the pipeline system.
A frequent cause of failure of old compressors is jamming of the mechanism due to oil burnout or wear products getting into friction pairs. Also, a break or interturn short circuit of the stator windings often occurs. To check the windings, use a multimeter, measuring the resistance between the contacts.
| Winding type | Wire color (standard) | Expected resistance | Probable malfunction |
|---|---|---|---|
| Startup | Red / White | High (20-50 Ohms) | Wire break |
| Working | Blue / Green | Low (10-20 Ohm) | Short to body |
| General | Black / Yellow | Sum of resistances | Failure of contacts |
| Case | Any contact | Infinity | Insulation breakdown |
If the resistance between any contact and the compressor housing shows at least some value (not infinity), it means the insulation is broken. It is strictly prohibited to operate such a unit, as it is mortally dangerous. The motor must only be disposed of.
The mechanical part can be damaged due to dry operation when the oil level has dropped to a critical minimum. In this case, deep scratches and burrs are visible on the cylinder bore and piston. Such parts cannot be restored at home; it is easier to replace the entire assembly.
Why does the compressor hum, but does not start?
Most often this means that the starting winding is intact, but the shaft is mechanically jammed, or the starting relay does not work. An attempt to start in this mode leads to rapid burnout of the windings and activation of the thermal protection relay.
Disposal and use of the old motor
After disassembly and diagnostics, it becomes clear what to do with the unit next. If the compressor is faulty mechanically or electrically, it is best to take it to a specialized collection point. The ferrous and non-ferrous metals contained in it can be recycled, which is more environmentally friendly than throwing it in a landfill.
However, if the electric motor is working properly, and the breakdown was in the mechanics or cooling system, such a motor can be used for other purposes. It makes excellent compressors s for airbrushing, inflating tires or supplying air to an aquarium. To do this, just connect a hose to the outlet pipe and provide power through a working starting relay.
When using an old engine in new conditions, it is important to remember its gluttony for oil. Oil mists will always be present in the output air flow, so it is necessary to install an oil separator or a fine filter, especially if you use air for painting or airbrushing.
The disassembled or mothballed compressor should be stored in a dry place, having previously sealed all openings to prevent moisture from entering the windings. Dampness is the main enemy of electrics; it will quickly lead to corrosion of contacts and destruction of insulation.
Frequently asked questions (FAQ)
Is it possible to restore a compressor if it is jammed?
In rare cases, “wedging” by applying increased voltage or mechanically turning the shaft helps, but this is a temporary measure. If scoring occurs on the piston group, a full repair at home is impossible; the unit needs to be replaced.
How much oil is inside the compressor?
Usually, household refrigeration compressors contain from 150 to 300 ml of technical oil. The exact volume depends on the model and performance of the motor; you can find it out in the technical documentation or experimentally when draining.
Is it dangerous to open the compressor yourself?
The main danger lies in the residual pressure of freon and the presence of electricity. If the system was properly prepared (freon was removed by professionals), then the risk is minimal. The main thing is to be careful with tools and sharp metal.
Is it possible to change the oil in a compressor without opening it?
Theoretically, you can try to pump out the old oil through the tubes and fill in new one, but the effectiveness of such a procedure is low. Most of the old oil will remain on the walls and in hard-to-reach places, mixing with the new one, which will not solve the lubrication problem.