How to connect a compressor from a refrigerator diagram. Compressor pressure switch: independent connection and configuration

To begin with, it is worth understanding how the compressor works and what function it performs. The essence of the compressor in all refrigerators is the same. It consists in pumping out the heated refrigerant from the evaporator and pumping it into the condenser, which is located on the rear wall of the unit. The condenser cools and liquefies the refrigerant; after that, it enters the evaporator and thus cools the air inside the chamber.

To connect the refrigerator compressor, you first need to deal with its device. Although the essence of the operation of this part of the apparatus is the same in all refrigerators, their scheme and arrangement may vary. Consider how it works using the example of an Atlant refrigerator compressor.

Most compressors modern refrigerators piston. As you can see in the photo, it consists of:

• casing of the motor-compressor;
• casing covers;
• the motor-compressor itself;
• stator;
• stator mounting bolt;
• compressor housings;
• cylinder;
• piston
• valve plate;
• crankshaft;
• crankshaft journal;
• the main journal of the shaft;
• backstage clips;
• slider backstage;
• injection tube;
• suspension studs;
• suspension springs;
• suspension bracket;
• shaft bearing;
• rotor.

The principle of operation is as follows: the motor drives the crankshaft located in the compressor housing. With the rotation of the shaft, the piston begins to work, performing reciprocating movements. Thus, it pumps out the refrigerant and sends it to the condenser. Further, the gas through the suction valve enters the chamber, which opens when a vacuum is created.

Before you connect the compressor from the refrigerator with your own hands, let's deal with the circuit and operation of the compressor relay.

Refrigerator compressor relay wiring diagram

The function of the relay is that it starts the engine, that is, the motor, thanks to which the compressor works. In order to understand how to connect it, you need to understand what it consists of.

The main elements of the starting-protective relay can be shown schematically:

• fixed contacts;
• moving contacts;
• core rod;
• core;
• bimetallic plate heater;
• thermal relay contacts.

Now let's go directly to the connection diagram of the refrigerator compressor.

To do this, we need a tester, a compressor and a starting relay. We set the tester to kiloohms or ohms, and measure the resistance between the compressor windings (there will be 3 of them). After measuring the resistance, we look where it turned out smallest value- this will be the working winding. This means that we will connect it to the relay and give it 220 volts.

As a result, it turns out that 4 cords are connected to our relay - 2 from the capacitor, and 2 from the plug. Next, we connect the relay directly to the compressor, and plug the plug into the outlet.

In this way, you can check the health of the compressor. On the one hand, we connected the relay, on the other, there are 3 tubes. Having turned on the compressor in the outlet, air should go out of one of the tubes, it should be sucked into the others.

Refrigerator Compressor Wedging Diagram

If, after connecting the compressor, it does not work, the mechanism may be jammed. You can avoid it without resorting to the help of repairmen. To do this, you need to do a wedging.

We only need a device that consists of two diodes. It should be connected to the windings of the compressor motor and give them a short-term voltage for 3-5 seconds. Then repeat the procedure after half a minute.

As a result of these actions, the mechanism is wedged, because the alternating torque that has arisen on the motor shaft causes the rotor to vibrate with a frequency of up to 50 Hertz. Thus, the vibration transmitted to the wedged compressor elements wedges them.

When performing this procedure, remember that diodes must have certain characteristics:

• indicator of permissible reverse voltage is more than 400V;
• the indicator of admissible direct current is not lower than 10 A.

Connecting the refrigerator compressor without condenser

In the composition of the refrigerator, the condenser plays one of the important roles. It exists for heat exchange - it removes condensing freon vapors that come from the compressor to environment. Also, the efficiency of the refrigerator, that is, its efficiency, increases to 20% in the presence of a capacitor. Good job condenser is the key to good operation of the refrigerator.

The refrigerator compressor is connected to the condenser and through the return pipe to the evaporator. If a breakdown of the capacitor is observed, then the operating current of the refrigerator will be greatly overestimated and this may lead to the compressor burning out.

If you decide to connect the refrigerator compressor to a network without a condenser, this can only be if this compressor is already used for another purpose. For example, in order to make a pump or apply it to an airbrush.

The scheme for connecting the compressor from the refrigerator in order to adapt it for other devices with your own hands is the same as when connecting it as part of the refrigerator (described above).

How to connect the compressor?

If you urgently need a compressor, and there is no time to go to buy it, you can take a compressor from an old refrigerator. Let's talk about how to connect the compressor to the necessary equipment.

How to connect a compressor: instructions

Please note that when removing the compressor from the refrigerator, be sure to cut the cable coming from the temperature sensor, otherwise you will not be able to pull it out. Then proceed as follows:

1. Install a relay on the compressor - this will help protect it from overheating and current surges. The relay must be installed according to the instructions that come with it.
2. Now equip the compressor with a receiver. If you use a purchased one, then connect it according to the diagram that comes with it. But you can make such a device yourself. Take a plastic bottle (1 liter) and make 2 holes in its cap with an awl. Install the outlet and inlet tubes there, and then pour epoxy into the container and turn it over. Then leave it all for a few hours. When the resin hardens, the cap with tubes will stick securely to the bottle. As a result, the resulting device will last for many years. It is connected to the discharge pipe, which is located next to the valve.
3. The last thing to do is connect the unit to necessary device. To do this, it is best to use hoses designed for windshield washer. They can be purchased at any automotive store. Hoses are installed in the holes of the compressor located on its upper part.

After you have connected the compressor, you need to turn it on and check for operability. If you have done everything correctly, then there will be no problems with its functioning.

When operating the compressor, you need to monitor the oil level in it. It is important that it does not drop to a critical level, otherwise the unit will overheat and quickly fail. At the same time, use oil with additives and mineral components for filling.

Please note that the operating time of the compressor from the refrigerator should not exceed 45 minutes. After that, leave the compressor alone for at least 10 minutes. When operating the compressor, do not forget about safety precautions: connect the device only with dry hands, make sure that the wires are isolated, do not allow it to overheat, and so on.

So, it's time to throw your old broken refrigerator into the landfill? Even if it is no longer repairable (for example, due to a freon leak), there are still valuable working units and spare parts on it that need to be removed! First of all, this concerns the compressor of the refrigerator. It will come in handy more than once for pumping air, for example, in wheels or for making a home-made paint sprayer - an airbrush. To remove the compressor from the refrigerator, you will have to unscrew only 4 nuts and cut off only 2 tubes with a hacksaw - inlet and outlet. The third tube (freon) is muffled tightly. copper tube in the immediate vicinity of the unit, you can just have a bite to eat with wire cutters, and not saw off. Of course, before proceeding with dismantling, the refrigerator must be unplugged!

The next step is to check the removed unit for operability. To do this, it must be connected to the electrical network. If the compressor is running, a hissing sound is clearly audible - air is sucked into one tube and thrown out into another. Remove the assembly from the old refrigerator as carefully as possible so that the oil in it remains safe and sound. You need to cut the cable going to the temperature sensor, then you need to measure the resistance and study the location of the closed contacts that will be used during further assembly, it is very good if the circuit diagram of the old refrigerator is preserved.

Preparatory work

Having determined the outlet pipe from the compressor, it is better to mark it immediately, because an oil filter will need to be attached to it. In order for the used compressor in the new device not to overheat and fail prematurely, it is better to install a new relay to it, ideally if the relay is original, corresponding to the brand of the old refrigerator. To connect the relay correctly, you need to study the refrigerator diagram and make the connection in exactly the same order that was in the refrigerator and which the diagram shows. If the documents for the refrigerator are not preserved, the circuit diagram can be found on the Internet.

Also new device you will have to equip a receiver that you can buy in a store or make yourself. Also needed for assembly plastic bottle, through the holes in the lid of which the inlet and outlet tubes will pass. After inserting the tubes, the bottle should be filled epoxy resin, moreover, the bottle should be cap down until the resin hardens. After the resin hardens, the tubes and the cap will be tightly mounted into the bottle.

To connect the air pumping unit to some kind of device, you will need windshield washer hoses, which, like a relay, can be bought at any car shop. During operation of the device, you should carefully monitor the oil level, which prevents overheating. It should also be remembered that the compressor from the old refrigerator should not work longer than 45 minutes.

How to check the wiring and connect the compressor from an old refrigerator without a relay and a circuit?

Many people are interested in connecting a compressor without a relay, and there are significant nuances here, information about which is quite difficult to find. It is not so much the scheme that is important here, but the principle. First you need to ring the general conclusion, which is located apart, to the left of the other two. Having attached the terminal to the common terminal, you need to find the working winding with the second terminal. For example, one output shows 14 ohms and the other shows 37.9 ohms. Which of these windings is working? Many mistakenly claim that the working winding is the one that shows more resistance. But this is fundamentally not true.

The working winding is the one that shows the least resistance! And the one that shows more resistance is the starting (starting) one! If you mix them up and connect the compressor incorrectly, it will quickly overheat and will not last long at all. Therefore, in this case, accuracy is needed!

This is the rule that works for refrigerator compressors, and this should not be forgotten. Next required preparatory stage before connecting, this is a check to see if any of the windings breaks into the case. Otherwise, it may happen that you touch the body of a working device, and you will be shocked. And this is not excluded, because the compressor is not new. To check, you need to touch the winding output with the left terminal, and with the right terminal anywhere on the body, test the second and third outputs in the same way. Only if the device has shown that all three outputs are reliable and do not break through, can such a compressor be connected to a working device.

The next step is to use the terminal blocks to connect the compressor from the old refrigeration equipment to tension. First - to the common wire and to the worker. And the starting voltage will be applied by briefly touching the bare wire. But this must be done carefully and carefully so as not to get an electric shock. When voltage is applied, the compressor starts to hum, and when we touch the start output, it turns on and starts blowing air. The optimal operating time is 10-15 minutes, during this time some heating of the unit body is allowed, up to 50 degrees, but more can not be allowed.

If the wiring is in order, you need to change the oil!

Of course, you can leave the old oil, but is it worth it to spend so much effort to connect old compressor to a new device for only a few sessions? Most likely, there is long-used oil inside, which contains metal particles and does not protect the unit from overheating well. It is best to completely drain the old oil and fill in new engine oil. Where to fill it is not a question. As a rule, a large bolt is clearly visible on the compressor housing, which must be unscrewed wrench. Through the open hole, the old oil is drained and the new oil is poured.

How to extend the life of the compressor?

Prevention of overheating and premature failure of the compressor is a sufficient amount of oil, correct connection to electrical outlets and time limit. It is not bad to connect a capacitor between the common and starting outputs, especially if it was in the refrigerator. This simple device increases the efficiency of the engine and extends its service life.

Budget models air compressors are not always equipped with a pressure switch, since similar devices are installed on the receiver. Therefore, manufacturers of this equipment believe that visual control of the pressure developed by the compressor based on the readings of pressure gauges is quite enough. At the same time, during long-term work, in order to avoid overheating of the engine, it is advisable to install a pressure switch on the compressor as well. Then the drive will turn on and off automatically.

The device and diagram of the pressure switch to the compressor

All compressor pressure switches are divided into two types:

• Switching off the compressor motor when the air pressure in the network exceeds the permissible limits (such designs are called normally open);
• Including the compressor motor when the pressure in the network drops below the permissible limits (such designs are called normally closed).

The actuating element of the pressure switch for the compressor are springs, the compression force of which is changed by a special screw. In the factory settings, the compression force of the springs is usually set to a pressure in the pneumatic network from 4 to 6 atm, as reported in the user manual. Since the rigidity and flexibility of spring elements depend on the ambient temperature, all designs of industrial pressure switches are designed for stable operation in the temperature range from -5 to +80ºС.

The design of the pressure switch includes two mandatory subassemblies - an unloading valve and a mechanical switch. The unloading valve is connected to the air supply line between the receiver and the compressor. It controls the operation of the electric motor. If the compressor drive is turned off, then the unloading valve on the receiver dumps the excess compressed air(up to 2 atm) into the atmosphere, thereby unloading the moving parts of the compressor from the excess force that they will have to develop when re-enabling compressor. This prevents a critical overload of the engine in terms of the permissible torque. When the unloaded motor is started, the valve closes and does not overload the actuator.

The mechanical switch performs the stand by function, preventing accidental starting of the engine. After pressing the button, the drive is switched on and the compressor operates in automatic mode. When the button is turned off, the compressor motor will not start even if the pressure in the pressure pneumatic network is lower than required.

In order to improve the safety of work industrial structures compressor pressure switches are also equipped with a safety valve. It is useful, for example, in case of a sudden stop of the engine, a broken piston or other abnormal situation.

Optionally, a thermal relay can also be mounted in the pressure switch housing, with the help of which the current strength in the primary circuit is monitored. If for some reason this parameter increases, then, in order to avoid overheating and subsequent breakdown of the windings, the thermal relay will turn off the electric motor.

How to connect and set up a pressure switch?

In general circuit diagram compressor unit, a pressure switch is located between the unloader valve and the secondary motor control circuit. Typically, the pressure switch is equipped with four threaded heads. One of them is designed to connect the device to the receiver, and the second - to connect the control pressure gauge. One of the remaining connectors can be used to install a safety valve, and the remaining one is a regular threaded plug with a ¼ inch thread. The presence of a free connector allows you to install a control pressure gauge in a place convenient for the user.

The pressure switch is connected in the following sequence:

1. Attach the device to the unloading valve of the receiver.
2. Install a control pressure gauge (if it is not necessary, then the threaded inlet is also plugged).
3. Connect to the contacts of the terminal of the motor control circuit (taking into account the selected connection scheme - to normally open or normally closed contacts). In case of voltage fluctuations in the network, the connection is not made directly, but through network filter. This is also required when the power for which the contacts are rated exceeds the power of the motor load current.
4. If necessary, adjust the relay to the desired values ​​​​of compressed air pressure with adjusting screws.

When connecting, it is necessary to check whether the voltage in the network corresponds to the factory settings of the compressor pressure switch. For example, in a three-phase network with a voltage of 380 V, the relay must have a three-contact group (two phases + zero), and for a voltage of 220 V - two-contact.

The adjustment is made when the receiver is not less than two-thirds full. To perform this operation, the relay is disconnected from the mains, and, by removing the top cover, the compression of the two springs is changed. The adjusting screw, on which the spring axis of a larger diameter is mounted, is responsible for the upper limit of the working pressure. On the board next to it, the generally accepted symbol for pressure (P - pressure) is usually indicated, and the direction of rotation of the screw is also indicated, with which this pressure decreases or increases. The second, smaller, adjusting screw is responsible for setting the required pressure range (difference). It is labeled symbolΔP, and is also provided with a direction of rotation indicator.

To reduce the setting time, in some designs, the adjusting screw for changing the upper pressure limit is brought outside the pressure switch housing. The control of the result is carried out according to the readings of the manometer.

DIY pressure switch

With known skills, as well as the presence of a working thermal relay from a decommissioned refrigerator, the pressure switch can be made independently. True, he will not have special practical capabilities, since the ability to hold upper pressure is limited by the strength of the rubber bellows.

Thermal switches of the KTS 011 type are most convenient for conversion into a compressor pressure switch, since they have a strictly reverse sequence of their operation: with an increase in temperature in cold store the relay turns on, and when it goes down, it turns off.

The essence and sequence of the work is as follows. After opening the lid, set the location desired group contacts, for which it is enough to ring the circuit. First, the connection of the thermostat to the compressor is being finalized. To do this, the outlet pipe, together with a control pressure gauge, is connected to the unloading valve, and the contact groups are connected to the terminals of the electric motor circuit. An adjustment screw will be found under the thermostat cover. When the compressor is turned on (the receiver must be filled with no more than 10 ... 15% of its nominal volume), the screw is sequentially rotated, controlling the result according to the pressure gauge. To set the lower position (determining the minimum air pressure), you will have to gradually move the stem of the face button. To do this, the cover is put in place, and the adjustment is actually done blindly, since there is nowhere to connect the second pressure gauge.

For safety reasons, the pressure adjustment range using such a thermal switch cannot be more than 1 ... 6 atm, however, using devices with a stronger bellows, you can increase the upper range to 8 ... 10 atm, which in most cases is quite enough.

After checking the operability of the relay, the capillary tube is cut off and the refrigerant located there is released. The end of the tube is soldered into the unloading valve.

Next, work is carried out to connect a home-made pressure switch to the compressor control circuit: with the help of a nut, the relay is connected to the control board, a thread is made on the stem, and a lock nut is screwed on, turning which, you can adjust the limits of air pressure change.

Considering that the contact group of any thermal relay from the refrigerator is designed for sufficiently large currents, in this way it is possible to switch circuits of considerable power, including secondary circuits compressor motor control.

In most cases inexpensive models air compressors are not equipped with a pressure switch, since such products are mounted on the receiver. Based on this, many manufacturers think that visual control of pressure through a pressure gauge will be more than enough. However, with prolonged use of the device, if you do not want to bring the engine to overheating, it makes sense to install a pressure switch for the compressor! With this approach, the shutdown and start of the drive will be carried out automatically.

Scheme and device

The device is divided into the following types:

• Starting the electric motor of the compressor when the pressure drops below the set value (normally closed);
• Switching off the engine when the air pressure rises above the normal mark (normally open).

Springs are considered to be the actuating element in the device. Their compression force is measured using a special screw. As a rule, manufacturers adjust the compression force of the springs in such a way that the pressure in the pneumatic network is in the region of 4-6 at. This parameter is always exactly indicated in the instructions.

Since the flexibility and stiffness of springs always largely depend on temperature, all elements of industrial pressure switches are designed and created taking into account subsequent operation at temperatures from minus 5 to plus 80 degrees.

The pressure switch provides for 2 mandatory subassemblies in its design - a mechanical switch and an unloading valve. The mechanical switch protects against accidental starting of the engine, thus performing the stand by function. After pressing the drive of the device starts, after which the compressor starts to work in automatic mode. Without pressing the button, the electric motor will not work even with reduced pressure in the pneumatic network.

The unloader valve is connected to the air supply line between the compressor and the receiver and is responsible for the operation of the engine. When the compressor drive is turned off, the unloader valve on the receiver disposes of excess compressed air, thus saving the moving parts from the extra effort required when restarting the compressor. This prevents the motor from being overloaded with torque. When the unloaded engine is turned on, the valve is closed, which prevents the creation of excess load.

For greater safety, pressure switches are supplied additionally. safety valves, which turn out to be very useful, for example, in case of a piston breakdown, a sudden stop of the electric motor, and in any other emergency!

A thermal relay can also be installed in the pressure switch housing, allowing you to monitor the current strength in the primary circuit. If this parameter is increased, the thermal relay will automatically turn off the engine, thus protecting the device from overheating and breakdown of the windings.

Connecting and setting the pressure switch

The pressure switch in the compressor unit circuit is located between the secondary motor control circuit and the unloader valve. As a rule, the pressure switch for the compressor is equipped with 4 threaded heads, one of which is designed to connect the control pressure gauge, the second - to connect the device to the receiver. One of the remaining ones is fitted with a ¼-inch threaded plug, the last one is safety valve. The presence of a free connector makes it possible to place the control pressure gauge in the most convenient place.

The connection of the pressure switch is carried out in the following order:

1. A device is connected to the unloading valve of the receiver.
2. A control manometer is located. Otherwise, the threaded entry is plugged.
3. The motor control circuits are connected to the terminal contacts. If the voltage in the network changes, then the connection should be made through the network filter! It is also necessary when the contact power exceeds the indicator for which the engine is designed.
4. If necessary, the compressed air pressure readings can be adjusted using the adjusting screws.

Before connecting the pressure switch to the compressor, it is worth checking the compliance of the mains voltage with what is indicated by the manufacturer! For example, a two-contact group is used for a three-phase network with a voltage of 220V, a three-contact group is used for a voltage of 380V.

Adjustment is carried out when the receiver is at least 2/3 full. To do this, the relay is disconnected from the power supply, after which, with the cover removed, the spring compression is adjusted. The adjustment screw with the axis of the larger spring is responsible for the maximum value of the working pressure. The second adjustment screw, with a smaller spring, allows you to adjust the pressure difference. In most cases, the manufacturer will indicate on the board the direction of rotation for increasing and decreasing pressure. Here you can also see the generally accepted designation of pressure - the Latin letter "P" and "ΔP".

In some models, to reduce the time required to adjust the pressure, the manufacturer places an adjusting screw outside the pressure switch housing. In this case, the result is controlled based on the readings of the manometer.

DIY pressure switch

If you have a working thermostat from an old refrigerator at home, as well as some work skills, then you can safely make a pressure switch for a compressor with your own hands. However, it is worth warning in advance that such a solution cannot differ in great practical possibilities, since the upper pressure with such an approach will be limited only by the strength of the rubber bellows.

It is most convenient to convert the KTS 011 thermal relay into a pressure switch, because they differ in the reverse sequence of operation - when the temperature in the chamber decreases, they turn off, when the temperature rises, they turn on.

Work order

After opening the cover, the location of the required group of contacts is found out, for this purpose the circuit is called. The first step is to refine the connection of the compressor with the thermal relay: the contact groups are connected to the terminals of the electric motor circuit, and the unloading valve is connected to the outlet pipe with a control pressure gauge. The adjusting screw is located under the thermostat cover.

When the compressor is started, the screw rotates smoothly, at the same time, you need to monitor the readings of the pressure gauge. It is worth taking care that the receiver is filled by 10-15 percent! To achieve the minimum pressure, it is necessary to smoothly move the stem of the face button. To this end, the cover is placed in its original place, after which the adjustment is performed almost blindly, since there is nowhere to install the second pressure gauge.

For safety reasons, it is not recommended to set the thermostat pressure beyond 1-6 atm! If devices with a stronger bellows are used, the maximum range can be raised to 8-10 atm, which is usually enough for most tasks.

The capillary tube is cut only after you make sure that the relay is working. After the release of the refrigerant inside, the end of the tube is placed inside the unloading valve and soldered.

The next step is a homemade pressure switch for the compressor is connected to the control circuit. To do this, the relay is fixed to the control board with a nut. The locknut is screwed onto the threads on the stem, thanks to which the air pressure can be adjusted in the future.

Taking into account the fact that the contact group of a thermal relay from any refrigerator is designed to work with high currents, they can switch quite powerful circuits, for example, secondary circuits when working with a compressor engine.