Start relay for a refrigerator: device, how to properly check and repair

Refrigerator start relay connection diagram

This part is needed to start an asynchronous single-phase compressor motor. There are no difficulties in connecting the relay. The starting and operating windings are connected to the motor stator. The first is involved in starting and starting the compressor, the second keeps the rotor in working condition and continuously supplies alternating current. There is a start-up relay that regulates the supply and turns off the power to the working and starting windings.

Inductive short circuit

Power is supplied to the input of the device: “zero” and “phase”, at the output the latter is divided into 2 lines. One is connected to the starting winding through the starting contact, the other is connected to the working winding of the motor. In the relay, current is supplied to the working winding through a spring, the resistance of which is quite high, then through a connection with a bimetallic jumper. This element has the property of bending in one direction under the influence of elevated temperature. As soon as the current in the circuit increases significantly, for example, if a short circuit occurs between the turns or the motor jams, the spring that comes into contact with the jumper heats up. The latter changes shape, after which the contact opens and the compressor turns off.

In order to start the motor in this circuit, a coil is used, connected in series with the working winding. When the rotor is stationary, voltage is applied, which causes an increase in the current in the coil. A magnetic field is formed, it attracts the movable core, which in turn closes the starting contact. After the rotor picks up speed, the current in the network decreases and the magnetic field decreases. The starting contact is opened by a compensating spring or gravity.

Posistor switching

The starter consists of a capacitor and a posistor, which is a type of thermal resistor. In the compressor circuit, the capacitor is installed between the buses of the starting and working windings. This mechanism provides the phase shift necessary for the compressor motor to turn on. The posistor is connected in series with the starting winding. When starting, its resistance is insignificant; at this moment a large current flows through the winding. When it passes, the posistor heats up and its resistance increases greatly. Because of this, the auxiliary winding is almost completely blocked. The part cools down after the voltage supply to the compressor stops.

Operating principle and design of the motor

The operation of a refrigerator of any model (Atlant, Indesit, Stinol) is generally the same. It is based on the circulation of refrigerant (freon) in the system. Initially, the refrigerant is a gas, the pressure created by the compressor causes it to enter the condenser. There the gas cools, turns into liquid and flows into the evaporator. When heated, the liquid returns to its primary state and repeats the cycle.

Therefore, if there are problems with the operation of the compressor, it will not create pressure or there will be insufficient pressure for normal operation.

The degree of cooling - the temperature in the chamber - is regulated by a thermostat. From it the signal goes to the motor start relay, which starts the whole process.

A motor-compressor is located on the rear side of the unit housing. It is fixed in a special oil and covered with a protective casing, which you can see in the picture.

The electric motor consists of a starting and operating winding, as well as a relay.

Three terminals are connected to the case, one of which is common. The other two lead to the start and run windings. The latest models of refrigerators are equipped with an electrical circuit that can regulate the speed of the engine.

Operating principle of refrigerator start-up relays

In order for an installation intended for storing food to operate properly and uninterruptedly, its technical condition should be carefully monitored.
It is much easier to do this if you know the operating principle of the most important components of the unit. The starting relay of the refrigerator, called a “switch” in everyday life, is responsible for the timely switching on of the starting winding during equipment startup, and also interrupts the current supply if the motor begins to rotate at a frequency of 75% of the maximum. A small part performs a number of important functions, so any malfunction can cause serious damage to the unit. The operating principle of the refrigerator start-up relay is quite simple; it is based on the properties of a bimetallic plate that changes shape when heated. The latter is heated by contact with a current-conducting coil. If the motor consumes a small amount of current, the spiral heats up slightly and does not affect the bimetallic plate. When the amount of current consumed increases, the heated spiral transfers heat to the plate, which in turn disconnects the contacts in the compressor power circuit. You can check the condition of the refrigerator starting relay using a tester - if the resistance between the contacts is zero, the device is working properly. If the circuit is broken, the “switch” should be replaced.

Why you shouldn’t hesitate to replace a faulty relay

Of course, folk “craftsmen” have already learned how to start a refrigerator without a start-up relay by connecting the contacts directly. However, experienced craftsmen categorically advise against doing this. In the refrigerator, each part carries its own payload. And the exclusion of any component from the electrical circuit is fraught with overloading of the mechanisms, overheating of the engine and, at best, breakdown of the motor-compressor, and at worst, a fire. Actually, the name of the part itself suggests that it is necessary for the correct start-up of the unit. And the protective part of the relay just saves the equipment from excessive thermal load. Simply put - from overheating.

So don't put off replacing it. When choosing, be guided by the brand and characteristics of the spare part removed from your refrigerator. Ideally, you should purchase exactly the same modification of the part and connect it to the refrigeration unit in the same way.

We hope you found our instructions for diagnosing and troubleshooting useful.

Refrigerator thermostat circuit

In the electrical circuit of the thermal relay there are 2 inputs from the power source: one is zero, the second is phase. The last input also splits into two: directly to the working winding and through disconnecting contacts to the starting winding.

If there is no seat for the relay, when connecting it to the compressor, you need to clearly know how to connect the contacts. The attached documentation will help with this, but you can disassemble the compressor to understand the location of the feed-through contacts.

There are symbolic meanings near the outputs:

• general output – C;
• working winding – R;
• starting winding – S.

Relays on refrigerator models differ in the method of mounting on the compressor or on the frame of the device. These devices have their own current characteristics. If you have to change the relay, this must be taken into account.

Checking the thermostat

If your refrigerator does not turn off for a long time, constantly works or does not turn on at all, then the thermostat may be to blame. The culprit must be dismantled, and a jumper must be placed on the remaining contacts. If the refrigerator turns on, check the thermostat itself. It is placed in a container with cold water, and the outputs are tested with a tester or the resistance at the output is measured.

If there is no sound signal or if resistance is present, the thermal relay is faulty and must be replaced.

Complete set of compressor automation unit

The relay design is a small-sized block equipped with receiving pipes, a sensing element (spring) and a membrane.

Mandatory subassemblies include an unloading valve and a mechanical switch.

The pressure switch sensing unit is made up of a spring mechanism, the compression force of which is changed by a screw.

According to the factory standardized settings, the elasticity coefficient is set to a pressure in the pneumatic chain of 4-6 at, as reported in the instructions for the device.

Inexpensive models of ejectors are not always equipped with relay automation since such devices are mounted on the receiver. However, during long-term operation, to eliminate the problem of overheating of engine elements, it makes sense to install a telepressostat

The degree of rigidity and flexibility of the spring elements is subject to the temperature of the environment, therefore absolutely all models of industrial devices are designed for stable operation in an environment from -5 to +80 ºC.

The reservoir membrane is connected to the relay switch. During movement, it turns the pressure switch on and off.

The unloading unit is connected to the air supply line, which allows excess pressure to be released into the atmosphere from the piston compartment. This relieves the moving parts of the compressor from excessive force.

The unloading element is located between the ejector check valve and the compression block. If the motor drive stops working, the unloading section is activated, through which excess pressure (up to 2 atm) is released from the piston compartment.

With further start or acceleration of the electric motor, a pressure is created that closes the valve. This prevents overloading of the drive and simplifies starting the device in switched off mode.

There is an unloading system with a time interval of activation. The mechanism remains in the open position when the engine starts for a specified period. This range is enough for the engine to achieve maximum torque.

A mechanical switch is required to start and stop the automatic system options. As a rule, it has two positions: “on.” and "off".

The first mode turns on the drive and the compressor operates according to the established automatic principle. The second one prevents accidental starting of the engine, even when the pressure in the pneumatic system is low.

Shut-off valves allow you to avoid emergency situations when elements of the control circuit fail, for example, a breakdown of the piston unit or a sudden stop of the motor

Safety in industrial structures must be at a high level. For these purposes, the compressor regulator is equipped with a safety valve. This ensures system protection in case of incorrect relay operation.

In emergency situations, when the pressure level is higher than the permissible norm, and the telepressostat does not work, the safety unit comes into operation and vents the air.

Optionally, a thermal relay can be used as additional protective equipment in the review device. With its help, the strength of the supply current is monitored for timely disconnection from the network when parameters increase.

To avoid burnout of the motor windings, the power is turned off. The nominal values ​​are set using a special control device.

Tips for checking your refrigerator compressor yourself

If you have any problems with the operation of your refrigeration equipment, you can try to diagnose it yourself. You must act carefully. Remember safety precautions. When using testing devices, it is important to make sure the connection is correct several times.

If a malfunction is detected, it is recommended to contact a specialist for repair. Trying to fix the problem on your own may make the situation worse. Therefore, you should not carry out complex repairs yourself. Especially if you are not sure of the correctness of the diagnostic results. Otherwise, you will have to purchase new equipment due to the complete breakdown of the old one.

Sources

• https://210101.ru/kuhonnaya/kak-prozvonit-kompressor-holodilnika.html
• https://pts.ru/proverka-kompressora-kholodil-nika-indezit-mul-timetrom/
• https://its-city.ru/kuhonnaya/kak-rasklinit-kompressor-holodilnika.html
• https://make-a-choice.ru/shema-podklyucheniya-kompressora-holodilnika/
• https://oholodilnike.ru/remont/kak-proverit-kompressor-rabochij-ili-net.html
• https://expluataciya-holodilnika.ru/holodilniki/chasti-holodilnika/kak-proverit-rabotosposobnost-kompressora-bytovogo-holodilnika-samostojatelno/
• https://dns-magazin.ru/v-kuhne/kak-proverit-kompressor-holodilnika.html
• https://dekamall.ru/remont/kak-proverit-kompressor-kholodilnika-poshagovaya-instruktsiya.html
• https://magazin-opo.ru/kak-remontirovat/kak-prozvonit-kompressor-holodilnika-multimetrom.html
• https://opt-orion.ru/kuhnya/proverka-kompressora-holodilnika-testerom.html

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Operating principle of the start relay

Despite the large number of patented products from various manufacturers, the operation schemes of refrigerators and the operating principles of starting relays are almost the same. Having understood the principle of their operation, you can independently find and fix the problem.

Device diagram and connection to the compressor

The relay circuitry has two inputs from the power supply and three outputs to the compressor. One input (conditionally zero) passes directly.

The other input (conditionally – phase) inside the device is split into two:

• the first passes directly to the working winding;
• the second passes through the disconnecting contacts to the starting winding.

If the relay does not have a seat, then when connecting to the compressor you must not make a mistake with the order of connecting the contacts. Methods common on the Internet for determining winding types by measuring resistance are not correct in general, since some motors have the same resistance of the starting and running windings.

The electrical circuit of the start-up relay may have minor modifications depending on the manufacturer. The figure shows a diagram of the connection of this device in the Orsk refrigerator

Therefore, it is necessary to find documentation or disassemble the refrigerator compressor to understand the location of the feed-through contacts.

This can also be done if there are symbolic identifiers near the outputs:

• “S” – starting winding;
• “R” – working winding;
• “C” – general output.

The relays differ in the way they are mounted on the frame of the refrigerator or on the compressor. They also have their own current characteristics, so when replacing it is necessary to select a completely identical device, or better yet, the same model.

Closing contacts using an induction coil

An electromagnetic starting relay works by closing a contact to pass current through the starting winding. The main operating element of the device is a solenoid coil connected in series with the main winding of the motor.

At the moment the compressor starts, with the rotor static, a large starting current passes through the solenoid. As a result, a magnetic field is created that moves the core (armature) with a conductive strip installed on it, which closes the contact of the starting winding. The rotor begins to accelerate.

As the rotor speed increases, the amount of current passing through the coil decreases, as a result of which the magnetic field voltage decreases. Under the action of a compensating spring or gravity, the core returns to its original position and the contact opens.

On the cover of the relay with the induction coil there is an “up” arrow, which indicates the correct position of the device in space. If it is placed differently, then the contacts will not open under the influence of gravity

The compressor motor continues to operate in the mode of maintaining rotor rotation, passing current through the working winding. The next time the relay will work only after the rotor stops.

Regulation of current supply with a posistor

Relays produced for modern refrigerators often use a posistor - a type of thermal resistor. For this device, there is a temperature range below which it passes current with little resistance, and above which the resistance increases sharply and the circuit opens.

In a starting relay, a posistor is integrated into the circuit leading to the starting winding. At room temperature, the resistance of this element is insignificant, so when the compressor starts operating, current flows unhindered.

Due to the presence of resistance, the posistor gradually heats up and when a certain temperature is reached, the circuit opens. It cools down only after the current supply to the compressor is stopped and starts skipping again when the engine is turned on again.

The posistor has the shape of a low cylinder, which is why professional electricians often call it a “tablet”

Algorithm for checking the motor-compressor

If the refrigerator starts without problems, then the fault lies in the start relay. If not, the problem is in the compressor, and the relay may continue to work. Regardless of whether you repair the refrigerator yourself or call a specialist, you can always order the necessary spare parts for the refrigerator at ALM-zapchasti. The part will cost less, and you will receive a warranty on the product. But the most important thing is that after a successful repair, your refrigerator will start on the first try and when you need it!

How to launch and check operation

After the repair, you need to check the starting relay; to do this, it should be connected to the refrigerator. If the device is connected correctly, but the unit does not start, the compressor may be faulty. To check its condition, it is necessary to disconnect the installation from the network, remove the “switch” and connect the contacts directly to the engine. Then you should turn on the thermostat and refrigerator. If the equipment starts without problems, the cause of the problem lies in the electrical circuit breaker. If the motor does not start working without a control device, the compressor has failed. In each of the above situations, it is advisable to contact a specialized service center.

When is verification necessary?

If the cold blower breaks, the equipment stops working. You need to call a specialist at home or call a service center. However, the opportunity is not always there. Not all people know how to check the health of a refrigerator compressor. To cope with the task, you should arm yourself with some knowledge.

Checking the device is necessary if:

• new equipment has been purchased, you need to make sure it is working;
• a used refrigerator is purchased and diagnostics are required;
• it is necessary to identify the cause of the failure.

Compressor problem?

1. Remove the compressor and start protection relay.
   There will be 3 contacts under it: the starting and working windings and the common one.
2. On modern (especially imported) compressors, the nameplate or stickers show the location of the contacts in accordance with the windings. If not, arm yourself with a multimeter and measure the resistance
   between them. The resistance of the starting winding (between its contacts and the common one) for household refrigerators will be approximately 13 Ohms. Working - 43-45 Ohms. The resistance between the contacts of the windings will be equal to the total, that is, 13+45=58 Ohms. Fluctuations are allowed depending on the power and model of the unit.
3. We make a simple device that simulates the operation of a start-up relay: we connect 2 two-wire wires to the plug, one of which is opened using a button. We connect the direct wire to the working winding, the open wire to the starting winding, the common wire to the common contact. Press the button and insert the plug into the socket. If the compressor is working properly, it will start. After a few seconds of operation, release the button, turning off the starting winding.

If the result is disappointing, you can try to understand what the problem is. But the value of this knowledge is questionable, because repairing a compressor in most cases costs more than buying a new analogue,

and not every office will undertake such labor-intensive work. But still:

• A problem that you may have noticed while making your “relay”. When trying to measure resistance, did the multimeter show a break? This means the windings are broken, there is no contact. The repair consists of rewinding them, but this is too painstaking work.
• Put the multimeter in ringing mode and check if it penetrates the housing. Bring one probe to the body, touch the other one to the contacts of the windings. If the device shows contact, there is a breakdown, the motor is broken.
• When operating for a long time under heavy load (never fill a freezer full of warm meat!) the compressor can become very hot. In this case, the insulation of the wires in the winding melts, and it begins to work without using all its power. The compressor gets very hot, cannot provide pressure to operate normally, and the thermal protection trips regularly.
• Other, more serious accidents, such as water hammer. You will definitely notice a loud rumble somewhere at the bottom of the refrigerator and, for the future, know that after this, the compressor can simply be taken for scrap.

“How is the start-up relay of a refrigerator replaced? Why does the relay fail? How to replace the start relay yourself? We will tell you about this in more detail"

Household and industrial refrigerators are a rather complex engineering embodiment. They consist of many components and electronic boards. All processes in refrigeration equipment are interconnected and the breakdown of one small spare part can paralyze the operation of the entire device. The same thing can happen due to the failure of the start-up relay. This component is designed to start the compressor in a timely manner. The motor is not able to start working on its own without this small box, which in turn also protects the compressor from overheating and wear. As soon as the motor begins to overheat, the relay opens the electrical circuit. The current does not enter the electrical circuit and the operation stops. This protects such an important unit from premature failure.

Types of compressors in refrigerators

Most often, piston-based compressors with bypass valves are used in everyday life, drawing in gas during discharge through one valve and pushing it out after compression through another. A conventional compressor, with a crank converting the rotation of the motor shaft into piston movement, is called a manifold compressor. Such units are installed on budget models. They are noisy and get very hot due to the large number of moving parts in the compressor.

Linear compressors have a compression chamber with a piston. The crankshaft is excluded from the system. The piston operates directly from the solenoid, converting alternating current into mechanical energy of the piston movement. Models in the mid-price segment are equipped with linear motors. The energy efficiency of compressors is higher; they belong to class A. Starting and stopping equipment according to the instructions of the thermostat is less noisy.

Inverter compressors are equipment for continuous operation with variable capacity to maintain the mode in the chambers. Quiet operation, high efficiency, and reliability of the entire system are a consequence of installing an electronic converter in a brushless motor. The incoming current with a frequency of 50 Hz is rectified and converted into alternating current of the desired frequency. This provides variable rotation speed. High cost and dependence on stable parameters on the power line are obstacles to introducing new products into all models.

All motor-compressors have a complex structure, hermetically pressed into the housing. Internal failures lead to replacement of the entire assembly. External components include a starting and temperature relay, frame mounting, and gaskets.

Rules for dismantling the thermal relay

If the refrigerator does not turn on at all, it will be impossible to carry out the diagnostics described above. The probable cause of the breakdown is an electrical failure of this element.

But a problem can also be a compressor malfunction, for example, a burnt out motor winding. To determine whether the thermostat needs to be replaced, it will have to be removed from the refrigerator for examination.

Typically, the thermostat is located next to the control knob, which is used to set the air temperature in the refrigerator compartment. Double-chamber models are equipped with a set of two such handles

First you need to unplug the refrigerator. Now you should find the place where it is located, as described earlier. Usually you need to remove the adjustment knob, remove the fasteners and remove the protective elements.

Then you need to carefully inspect the device, paying close attention to the wires through which the power is supplied. All of them have different color markings depending on their purpose.

Typically, a yellow wire with a green stripe is used for grounding. This cable should be left alone, but all the others should be disconnected and shorted together

All of them have different color markings depending on their purpose. Typically, a yellow wire with a green stripe is used for grounding. This cable should be left alone, but all the others should be disconnected and shorted together.

Now the refrigerator is plugged in again. If the device still does not turn on, the thermostat is probably working properly, but there are serious problems with the compressor.

If the refrigerator does not turn on at all, the cause may be not only a malfunction of the thermostat, but also a breakdown of the compressor, for example, a burnt-out motor winding

If the engine starts working, we can clearly conclude that the relay needs to be replaced. Before starting work, it doesn’t hurt to arm yourself with a smartphone or camera in order to consistently record all operations. When installing a new thermostat, these pictures can be very helpful, especially for beginners.

You need to clearly remember which cable core was used for what purpose. Typically, a black, orange or red wire is used to connect the thermal relay to the electric motor. A brown wire leads to zero, a yellow-green wire provides grounding, and a pure yellow, white or green wire is connected to an indicator light.

To connect the thermal relay, wires with different color markings are used; you need to remember the purpose of each wire so as not to get confused during reassembly

Sometimes removing a damaged regulator can be difficult, especially when it is placed outdoors. For example, in some Atlant refrigerator models you have to completely remove the chamber door from its hinges. To do this, you need to remove the trim that is installed above the top hinge and unscrew the bolts hidden under it.

Before removing the adjustment knob, you also have to remove the plugs and unscrew the fasteners. All these operations must be done carefully. It is better to store fasteners and linings in a small container so that they do not get lost. The thermostat itself is usually screwed to the bracket; it must be carefully removed, unfastened and removed.

If the thermostat is located inside the refrigerator compartment, it is usually hidden under a plastic casing, where a lamp for illumination can also be mounted

A new thermostat is installed in its place, following the reverse assembly order. Sometimes the breakdown of the thermostat is associated with a malfunction of the so-called capillary tube or bellows. If you replace only this element, the relay can be left.

To perform this procedure, you will have to remove the thermal relay, following the method described above. The bellows must be disconnected from the evaporator and carefully removed from the device body. Now a new capillary tube is installed, connected to the evaporator, and the relay is mounted in its original place, and the disconnected wires are connected.

How to remove a relay from a refrigerator

Before starting any repair work, you should make sure that the refrigerator is unplugged and the plug is removed from the socket. Failure to do so may result in severe electric shock.

Relays of the RTP type are removed by simply disconnecting the contacts. If the refrigerator is not new, the contacts may oxidize and “stick”; in this case, you should pick them up in the connector with a thin flat-head screwdriver, wobble them, and then gradually move the connector until the contact plate comes out completely.

To remove a part from the refrigerator, you must first determine how it will be installed. The following methods are used:

• on screws;
• on rivets;
• on latches.

First the connectors are disconnected. Next, unscrew the screws securing the relay. If the device is secured with rivets, they should be carefully drilled out at low speeds with a drill or screwdriver. Experts recommend securing the new device with screws.

Important! Immediately after disconnecting the contacts, mark the wires. This is especially important on older refrigerators, where the wires may darken or change color over time.

The latches are pressed with a flat screwdriver until the relay is released. Care must be taken when doing this, especially on older refrigerators, as the plastic of the latches becomes brittle over time.

The principle of operation of the refrigerator relay

A starting electromagnetic relay operates on the principle of closing a contact, which is designed to pass current through the starting winding. The main operating element is the solenoid coil. It is connected in series to the main winding of the motor. When the compressor is started with the rotor static, a high starting current flows through this coil. This results in the creation of a magnetic field. It moves the core on which the bar is placed that conducts the current. It closes the contact on the starting winding. The rotor begins to accelerate. As soon as its speed increases, the current and voltage decrease. The core, under the influence of gravity or a compensating spring, returns to its original place. This causes the contact to open. The electric motor maintains the rotation of the rotor and passes current through the working winding. Therefore, the relay is activated only after the rotor stops.

Short circuit to the housing - how to check the refrigerator motor

A short to housing often causes compressor failure. The initial insulation resistance of the motor is 1000 MOhm; during operation, the quality of the insulation deteriorates and the resistance value drops to 100 or even 10 MOhm. When the value drops to 1 Megaohm, the motor must be replaced, and when measuring below 500 kOhm, it is prohibited to use the equipment.

Therefore, before diagnosing, it is necessary to check the engine for breakdown, so as not to receive an electric shock from a faulty device when checking the energized current. To measure, you can use a multimeter, ohmmeter or megohmmeter.

• Unplug the refrigerator.
• Remove the compressor panel, if equipped.
• Remove the starting or starter relay from the motor contacts.
• Switch the tester to resistance measurement mode.
• Look for any peeling paint on the engine housing. Or clear a small area.
• Attach one probe of the device to the lower left or right contact, and the second to the motor housing.

• Check the indicator. In a working engine, the tester will show the value as “infinity”. If the insulation is broken, a value close to zero will appear on the screen.
• The most accurate indicator will be given by a megohmmeter or multimeter with a constant voltage mode of 500 V.

Attention! If you find a breakdown of the windings, call a technician. Using a refrigerator with such a compressor malfunction is life-threatening.

What is the difference between a short to ground and a short to ground? An engine shorted to ground will produce a complete zero, and most likely will not work. When shorted to the body, the resistance has a low value, but differs from zero. The circuit breaker does not respond to such motors, but they are dangerous to operate and require replacement. The RCD also does not respond to a short circuit to the housing, because there is no current leakage in the refrigerator circuit, there is only voltage on the compressor casing.

How to check the operating parameters of a refrigerator compressor

If there is a malfunction or lack of switching on, you need to check the resistance with a multimeter, since if there is a breakdown, it can cause an electric shock. In other words, a tester test is carried out to examine the winding to identify its damage. Masters call this calling. You can initially check the serviceability of the refrigerator compressor using 3 main parameters.

You can check the operating parameters of the refrigerator compressor, but this requires certain knowledge

Namely, by:

• Resistance;
• Pressure;
• Toku.

If the winding is truly damaged, the voltage level may jump and be transferred to the surface of the housing. Typically, this can happen with older devices.

The serviceability of refrigeration equipment is checked by measuring the resistance in each of the 3 contacts present, together with the equipment body, and it is important that there is no paint present in the place where the ringing is carried out. If the resistance of the windings does not change and there is no damage, then the infinity icon will light up on the display of the diagnostic device

Otherwise, the compressor can be called faulty.

It is necessary to correctly connect the terminals of the simulator in the posistor to the cavity of the discharge fitting, connect everything securely, and then the indicators are taken precisely when the compressor is turned on. If the display displays a pressure of 6 atmospheres and the number begins to increase, then the diagnostics confirm the functionality of the device. If the pressure is lower or begins to drop, the pressure housing must be replaced.

It is equally important to call and find out whether the thermal starting relay is working, which will allow you to determine whether current is supplied to the motor. It is advisable to take as a basis the relay in working condition, which is confirmed by testing, and then use a device such as a multimeter with a clamp

After connecting the operating relay to the compressor cavity, a multimeter is required. This is done by clamping one of the wires using pliers. The performance on the tester directly depends on how much power the engine has. For example, if the power is 140 W, then the display will allow readings of 1.3 V. If the power is 120 W, then the readings can vary between 1.1-1.2 V. In this case, the start-up relay is operational and suitable for operation , however, most often it happens that the compressor is broken, and experts recommend starting the check with it.

Replacement instructions

If, during diagnostics, it was determined that interruptions in the operation of the refrigerator are associated precisely with a breakdown of the relay, the part should be replaced.
You can turn to professionals, but even a beginner can make the replacement. It is enough to follow all the recommendations of specialists and perform all manipulations extremely carefully. Procedure:

1. Open the special cover or get to the engine compartment in another accessible way.
2. Determine where the relay is located and remove the safety valve from it.
3. Carefully disconnect the part from the motor contacts.
4. Carefully inspect the starter box. It is important that there is no mechanical damage on it.
5. Using a multimeter, check the resistance of the posistor and thermal protection.
6. If it is discovered that the part has burned out, it is worth checking the resistance of the compressor windings.
7. If the resistance is acceptable, install a working mechanism.

After all the manipulations, it is important to check the operation of the refrigerator. You need to connect it to the network and listen to how the motor functions. If everything is in order, the part was replaced correctly and it was its failure that caused the malfunction of all equipment. If the problems remain the same, the problem is in other elements that have failed. In this case, it is better to hire a professional technician.

Purpose

After the compressor engine starts, the pressure in the receiver begins to increase.

If the excitation rheostat slider R is moved, then a resistor will be introduced into the SHOV winding circuit. The presence of a free connector allows you to install the control pressure gauge in a place convenient for the user. Control the pressure using the pressure gauge and set the required values.

Other names are telepressostat and pressostat. To do this you will have to: Disconnect the wiring from the contacts; Cut through the motor tubes connecting it to other parts; Image 4 - biting the motor tube Unscrew the mounting bolts and remove from the casing; Disconnect the relay by unscrewing the screws; Image 5 - disconnecting the relay Next, you need to measure the resistance between the contacts; By applying the tester probes to the output contacts, normally you should get OM depending on the model of the engine and refrigerator. The working system consists of springs of different levels of rigidity that respond to changes in pressure.

There may also be other auxiliary mechanisms that require activation: a safety or unloading valve. Types of pressure switch devices There are only two variations in the design of the automatic compressor unit. With the help of a relay, it becomes possible to operate automatically while maintaining the required compression level in the receiver.

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Air compressor made from auto parts

It is the largest supplier in the CIS. Scheme of automated control of an electric compressor The second contact PB1 turns on the signal relay P2 after 15 s; its closed contact can trigger an alarm, but by this time the pump mounted on the compressor manages to create the required pressure in the lubrication system, and the oil pressure switch RDM opens, interrupting alarm circuit. Control circuit for the electric drive of the fire-ballast pump When power is supplied to the circuit, even before the engine starts operating, the electromagnetic time relays RU1, RU2, RU3 acceleration relays are activated. This indicator must be less than the nominal pressure of the air blower.

Typically, the difference value is set to 1 bar. If the relay malfunctions and the compression level in the receiver rises to critical values, then in order to avoid an accident, the safety valve will operate, releasing the air.

Restarting with the KnP button is possible when contact Rв in its circuit is closed, which corresponds to the position of the Rв slider on the right. The operating system is made up of spring mechanisms with varying degrees of rigidity, reproducing the response to fluctuations in the air pressure unit.

If the pressure switch was found to be the source of the malfunction, the professional will insist on replacing the device. In addition, the pressure drop in the system will be significant. Install a control pressure gauge if it is not necessary, then the threaded inlet is also plugged. Compressor cannot gain speed REPAIR bad start FORTE VFL-50

Where is the compressor located in the refrigerator?

This unit is located at the rear of the device in its lower part. The compressor refers to the main part through which the refrigerant circulates in the thermal system. Depending on the purpose, two units can be installed in the refrigerator. The compressor is driven by a motor. Modern improved models of devices are equipped with piston compressors, with an engine installed inside them.

Piston devices are less likely to break down because they eliminate the loss of refrigerant.

Current type protection relay

An asynchronous motor is a complex electrical device that is prone to breakdowns. If a short circuit occurs, the circuit breaker installed in the distribution panel will trip.

If the fan, which cools the winding and mechanical moving elements, fails, the built-in thermal protection of the compressor will react.

However, a situation may arise when the motor begins to consume 2-5 times more rated current for a long time (more than 1 second). Most often this occurs when there is an unplanned load on the shaft resulting from a jammed motor.

The current increases, but does not reach the short circuit values, so the machine selected for the load will not work. There is also no reason for the thermal protection to turn off, since the temperature will not change in such a short period of time.

The only way to quickly respond to the situation and avoid melting of the working winding is to trigger the current protection, which can be installed in different places:

• inside the compressor;
• in a separate current protection relay;
• inside the start relay.

A device that combines the functions of turning on the starting winding and current protection of the motor is called a starting protection relay. Most refrigerator compressors are equipped with just such a mechanism.

The action of current protection is based on three principles:

• as the current increases, the resistance increases, which leads to heating of the conductive material;
• under the influence of temperature, the metal expands;
• The thermal coefficient of expansion differs for different metals.

Therefore, a bimetallic plate is used, which is welded from metal sheets with different expansion coefficients. Such a plate bends when heated. One end of it is fixed, and the other, deviating, opens the contact.

The plate is designed for a temperature response when a current of a certain strength passes. Therefore, when replacing the start-up relay, it is necessary to check its compatibility with the installed compressor model.

Everything you need to check your compressor

How to check whether the refrigerator compressor is working or not? To answer this question, we will first have to prepare the following set of instruments and tools:

• a set of screwdrivers with different profiles or a screwdriver with a set of attachments;
• wrenches with nominal values ​​of 8, 10 and 12 mm (corresponding screwdriver attachments);
• side cutters, pliers;
• universal type laboratory pressure gauge;
• megohmmeter, multimeter (tester);
• 2-3 conductor jumpers with alligator clips;
• electrical tape, rubber or vinyl plugs;
• personal protective equipment when working with hazardous substances.

About verification

This procedure is necessary if there are problems starting a household appliance. Ignoring them will lead to its complete exit from the operating mode. It is easier to prevent serious violations by checking the start relay in a timely manner. This part is necessary to prevent malfunctions if the temperature drops.

Changes lead to the closure of the contacts of the thermostat, as a result of which the starting relay starts the motor-compressor. All this happens in 2-3 seconds. If the expected reaction does not occur, that is, the motor does not go into operating mode, all that remains is to carry out diagnostics and correct the problems that have arisen. You can do this yourself or with the help of a wizard.

Rear panel of the refrigerator

To check the refrigerator start relay, you must follow the instructions:

1. We carry out a visual inspection of the mechanism. The start relay will function as expected if locked in a vertical position. Otherwise, the core, which is part of the coil, will not have time to retract within the allotted period of time. To avoid errors, there is a special mark on the device. If the relay is in the correct position, then the error should be looked for elsewhere.
2. We place the mechanism on the desktop for further manipulations:

• relays of the RTK-X and RTP-1 brands are placed with the arrow pointing down;
• place the part with the designation LS-08B with its back surface facing up;
• The DXR device is placed so that the terminals are visible.

1. Check for contact between terminals