The compressor is the heart of any refrigeration unit, and it is its failure that most often leads to a complete stop in the operation of the unit. Owners of household appliances often wonder about the possibility of restoring the functionality of this unit, hoping to save on the purchase of new expensive equipment. However, disassembling an electric motor a refrigerator is a complex technical process that requires not only specialized tools, but also a deep understanding of the design of sealed systems.
Before proceeding with dismantling, it is necessary to clearly understand that modern household compressors are designed as non-dismountable sealed units. The factory welding of the housing is done to ensure absolute vacuum tightness, and violation of this integrity almost always leads to the impossibility of high-quality resealing at home. However, for educational purposes or if you have professional equipment for overcooking the case, an understanding of the internal structure is necessary.
In this article we will look in detail at the stages of opening the case, the internal electrical part and the mechanical components of the piston group. You will learn what tools are required to carry out the work safely and why in 90% of cases disassembly does not lead to a successful repair, but only states the fact of final breakdown. Remember that inside the case there may be liquefied refrigerant under pressure, the residual vapors of which may be flammable or toxic.
⚠️ Attention: Before starting any work on the compressor, make sure that the refrigerant is completely vented in a well-ventilated area or outdoors, since freon displaces oxygen and can cause suffocation in a confined space.
Required tools and workplace preparation
Organizing the workspace is the first and critically important stage on which the safety of the master and the safety of parts depends. Since the process of opening the case involves the use of force and cutting tools, the surface must be stable and the lighting must be bright and directional. You will need a sturdy workbench or table that can support the weight of a heavy metal compressor cylinder.
The main difficulty is getting past the factory weld that connects the top and bottom of the casing. To do this, you will need a specialized tool, which is not always in the arsenal of a home craftsman. The use of unsuitable tools can lead to damage to the internal copper tubes or stator windings even before the diagnosis begins.
The list of required equipment includes both hand and electric tools. It is important to prepare everything in advance so as not to interrupt the process, since internal parts can oxidize during prolonged contact with moist air after opening.
- 🛠️ Angle grinder (grinder) with a thin cutting disc for metal for neat cutting of the weld seam.
- 🔨 Set of metalwork tools a chisel and a heavy hammer for separating the body halves after cutting.
- 🔧 A set of screwdrivers with insulated handles and a set of spanners for dismantling the electrical part.
- 🧤 Safety glasses and thick gloves to protect against metal shavings and sharp edges.
Special attention should be paid to diagnostic equipment. Before physically disassembling the unit, it is necessary to carry out electrical measurements. A multimeter will allow you to check the integrity of the windings and the absence of a breakdown on the housing, which will confirm the need for deep disassembly.
Removing the compressor from the refrigeration unit
The process of removing the motor-compressor from the refrigerator precedes its immediate disassembly and requires caution. First, you must completely disconnect the refrigerator by unplugging the plug from the socket and provide access to the rear of the unit. Often the compressor is closed with a metal or plastic casing, which is secured with latches or screws.
After removing the protective casing, you will have a view of the capacitor grill itself. It is important not to damage the copper tubes connecting the motor to the cooling system if you plan to reuse them or if the integrity of the circuit has not yet been compromised. Otherwise, if the refrigerator is beyond repair, you can cut the tubes with wire cutters. compressor and a capacitor grid. It is important not to damage the copper tubes connecting the motor to the cooling system if you plan to reuse them or if the integrity of the circuit has not yet been compromised. Otherwise, if the refrigerator is beyond repair, you can cut the tubes with wire cutters.
The compressor itself is attached to the frame of the refrigerator through rubber shock absorbers, which dampen vibration during operation. These elements often harden over time, so removing them may require some force or the use of pliers. Be careful not to tear the rubber bushings if you plan to reuse them.
☑️ Dismantling checklist
The electrical connection also requires attention. The terminal block is usually covered with a plastic cup, which can be removed by simply sliding it. Before disconnecting the wires, it is recommended to take a photo of the connection diagram so that if you reassemble it, you do not confuse the phase, neutral and ground.
⚠️ Attention: Never try to tear off the compressor by force without making sure that all the tubes are broken. A sharp jerk can damage the valves sealed inside the housing or deform the engine mount.
Opening the sealed compressor housing
The most important and dirty stage is breaking the tightness of the metal cylinder. Factory welding is performed around the junction of two hemispheres, and it is this seam that needs to be processed. There are two main methods: mechanical cutting with a grinder and knocking out the seam with a chisel. The first method is cleaner and safer for the insides, the second requires a lot of skill.
When using an angle grinder, you must make the cut extremely carefully, controlling the depth of immersion of the disc. The goal is to cut the weld but not touch the internal walls or windings that may be in close proximity to the edge. It is better to make several shallow passes than one deep and risky one.
After the circular cut is made, a flat chisel is inserted into the groove. With light blows of a hammer, it is necessary to wedge the halves of the body. If the cut is made well, the body will separate without significant effort. If you use the method of knocking out the seam without first sawing, the blows are applied to the edge of the seam, which often leads to deformation of the edges and complicates subsequent assembly.
Why can’t you just unscrew the bolts?
Modern compressors do not have threaded connections on the housing, since any thread is a potential leakage point for freon under high pressure. Tightness is ensured only by a continuous weld, which can withstand pressure up to 30 atmospheres.
Inside you will see oil, which may be dark and have a burning smell. This is the first sign of wear or overheating. Draining the oil into a prepared container will allow you to better examine the internal structure and troubleshoot parts.
Electrical part design and winding diagnostics
After removing the top cover of the casing, the technician has access to the electrical part and the stator. The central place is occupied stator with coils wound on it. It is here that an electromagnetic field is created that rotates the rotor. The windings are made of copper wire and filled with a special dielectric varnish to protect against moisture and vibration.
A terminal group is suitable for the stator, on which a start-protective relay and a starting capacitor (in some models) are attached. The relay is responsible for short-term connection of the starting winding at the moment the engine starts. Often it is the burnout of the relay contacts or the jamming of its mechanism that causes the refrigerator to hum without starting.
For diagnostics, it is necessary to visually inspect the windings for blackening, swelling or obvious wire breaks. However, a visual inspection is not always informative, so it is necessary to use a multimeter in resistance measurement mode.
- ⚡ Checking the operating winding: the resistance is usually from 10 to 30 Ohms.
- 🚀 Checking the starting winding: the resistance is higher, usually from 30 to 60 Ohms.
- 🔌 Breakdown test: the resistance between any contact and the housing must be infinite.
If the multimeter shows infinity on the working winding, it means that the wire has broken, and electric motor requires rewinding, which is almost impossible at home. If the resistance is close to zero, there is an interturn short circuit.
Mechanical part: crank mechanism
The heart of the mechanical part is the crank mechanism, which converts the rotational movement of the engine shaft into the translational movement of the piston. The engine shaft is a continuation of the rotor and is rigidly connected to the eccentric on which the connecting rod is placed. This entire system is immersed in an oil bath to lubricate the rubbing pairs.
A piston made of special steel or alloy moves inside the cylinder, compressing freon gas. The gap between the piston and the cylinder walls is minimal, so the ingress of solid particles or oil breakdown products leads to scoring and jamming. It is jamming (“knocking”) that is a common reason for the compressor to stop.
The valve system is located directly on the cylinder or in the block head. Thin steel petals act as check valves, allowing gas to flow in only one direction. Their breakdown or loss of elasticity leads to the compressor working, but not creating the required pressure.
| Element | Function | Typical malfunction | External sign |
|---|---|---|---|
| Piston | Refrigerant compression | Scuffing, ring wear | Knock, lack of pressure |
| Connecting rod | Gear effort | Wear of liners | Knock, play |
| Valves | Flow direction | Breakage of petals | Noise, lack of cold |
| Suspension | Vibration dampening | Breakage of springs | Strong vibration, noise |
Inspection of mechanics requires cleanliness. Parts must be washed in solvent or Galosh gasoline to remove old varnish deposits and oil combustion products. Any scratches on the cylinder bore or on the piston are critical.
⚠️ Attention: It is strictly forbidden to grind or polish the internal surfaces of the cylinder and piston with abrasive materials. Violation of the factory geometry and roughness will lead to immediate failure of the unit after assembly.
Difficulties of reassembly and sealing
It is extremely difficult to assemble a disassembled compressor back so that it operates reliably and safely. The main problem is restoring the tightness of the housing. Factory welding with argon or shielding gases at home cannot be reproduced with a guarantee of quality. The use of sealants or epoxy resins will not withstand internal pressure and vibration.
Even if it is possible to mechanically connect the halves of the housing, the question of vacuuming the system arises. After disassembly, air and moisture get inside. Moisture in the refrigerator cooling system turns into ice plugs that block the circulation of freon, and also reacts with oil, forming acid that corrodes the windings.
The restoration process requires a vacuum pump, a pressure gauge station and a supply of refrigerant. It is necessary to create a deep vacuum inside the system to evaporate the moisture, and only then fill the unit with gas. Without professional equipment, these procedures are impossible.
There is a technique for replacing the valve group without completely disassembling the housing, through drilled holes, but it requires jewelry precision and also does not guarantee durability. In most cases, technicians recommend replacing the compressor assembly.
Frequently asked questions (FAQ)
Is it possible to repair a refrigerator compressor yourself without welding?
A full repair with replacement of the piston group or windings without welding is impossible. You can only replace the start relay or capacitor if the fault lies in them. Opening the housing without subsequent professional cooking will result in the impossibility of operation.
Why does the compressor hum but does not start?
The most likely reason is a malfunction of the start relay or jamming of the piston group. A break in the starting winding is also possible. Diagnostics with a multimeter and checking the free movement of the shaft are required.
What kind of oil should be poured into the refrigerator compressor?
Special synthetic or mineral oils are used (for example, POE or Mineral), which have low hygroscopicity and are designed to work with a specific type of freon (R134a, R600a). Regular motor oil cannot be used.
Is the gas inside the compressor dangerous?
Modern refrigerants (R600a - isobutane) are explosive when concentrated in air. R134a does not burn, but when heated by a burner flame it can release phosgene, a chemical warfare agent. The work should be carried out in a ventilated area.
Is there any point in taking a disassembled compressor to a workshop?
No, workshops do not restore the tightness of opened casings. The cost of overcooking, vacuuming and refueling will exceed the cost of a new compressor. Disassembly makes sense only for recycling non-ferrous metals (copper) or training.