Checking the microwave transformer with a multimeter under voltage

Transformer in microwave oven how to check with a multimeter

The transformer for the microwave is an important link in the chain generating microwave radiation. This is a voltage converter to the size supplied to the input of the magnetron. A high.voltage converter often causes a breakdown of a microwave oven.

Checking the transformer for performance is an obligatory point in the list of technical diagnostics measures to find out the causes of the malfunction. Since we are talking about high stresses, independent intervention is possible only if all safety measures are observed.

Where to get high voltage?

Food in microwaves is warming up due to the work of ultra-frequency waves. Generates microwaves of a special emitter. magnetron. To work in the specified characteristics, he needs high voltage. 2,000 in. This is almost an order of magnitude higher than what the household power supply gives (220 V).

Where are the kilo of the kilo? They are created at the output of the secondary winding of the high.voltage converter.

Important! SCHCH, even disconnected from the mains, can hit the electric current (U up to 5,000 V).

Common breakdowns

Due to the fact that magnetron is not an integral part, but an integral one, a breakdown can occur with one of its elements. Depending on the reason, the repair may be simple or complex.

• In the magnetron of the microwave there is a special cap. Its task is to create a vacuum in the pipe. If the audit showed that it is faulty, then the repair is simple and will be able to even the non.specialists.
• If the part is warming up, then the radiator is out of order, it will need to replace and do it independently.
• Among the elements of the magnetron there is a thread of incandescent. Sometimes, as a result of overheating, it can break. Check is carried out by a tester. In working condition, it shows 5-7 ohms, if the thread is damaged, then the value will fall to 2-3 Ohms, if it is torn, then the indicator will be infinity.
• You should also check the high.voltage diode. Due to the fact that it consists of several diodes, a visual inspection of the part will not help. Here you need to use the multimeter. Connect the device to the plus and minus on the diode. In this case, on the plus, the value should be final, the infinity should be displayed on the minus. If the values ​​differ, then the diode is broken, or rather, one of its components. Repair is carried out in the service center.
• High.voltage transformer. To check it for performance, it is necessary to measure the voltage on its windings, however, there is a danger. the voltage can reach about 2 kW. For verification, not voltage is measured, but the resistance on each winding. To this end, the transformer disconnects from all wires that are connected to it. The further process is carried out with a megommeter. To understand the indicators normal or outside the norm, use the table, while the indicators in it differ for different manufacturers. Without even resorting to a special device, one can understand that it was the transformer that broke down in the microwave. The signs are as follows. a strong buzz, carbonization on the reel of the winding, excessive heating, the smell of burning.
• The multimeter will also allow you to check the fuse. Due to the jump in voltage or failure in the electricity network, it can burn out. In this case, when it calls it, the value will differ from zero. Before changing the fuse, you should check the primary, secondary and protective switch. If the cause is in them, then the new fuse will also immediately burn. This moment should be taken into account when repairing.

The principle of action and design of the magnetron

Many owners of the microwave oven, studying the instructions for its operation, wonder: “What is magnetron and how it works?””. Magnetron (from Greek. Magnetis-magnet, electron) in the radio electronics is called a powerful vacuum radio lamp, which includes:

• cylindrical anodusonator made of copper;
• Cathode in which the thread of the intensity is built;
• Ring magnets installed on the ends of the lamp.

The microwave magnetron is an electronic high.power lamp that can generate microwaves. This is due to the interaction of the cathode and the anode, which provokes the emergence of the magnetic field. Microwave radiation, which is released during the operation of the magnetron, is able to influence water molecules that are in food. As a result of radiation, the molecules produce fluctuations, which become source of friction, due to which heat arises, warming food from the inside

The principle of operation of the magnetron is to inhibit the flow of electrons in the electric and magnetic fields crossing at an angle of 90 °. The distribution of the magnetic field formed by end magnets is provided by a magnetic circuit, the role of which is played by the external casing of the magnetron, equipped with a flange of its attachment to the waves. The interaction of the flow of electrons emitted from the cathode is caused with this magnetic field, the appearance of microwave waves, which are captured by a wire loop and removed out with the help of a radiating antenna placed in a ceramic cylinder. As an antenna, a special tube (stengel) is used, with which air was pumped out of the lamp. A metal cap is tightly pressed on it.

Connection of the magnetron.

In the process of work, the magnetron is very heated, therefore, a plate radiator is provided in its design, which is also blown by a fan. In addition, the device is equipped with a thermostat. The penetration of high.frequency radiation on the wires of power supply is prevented by a high.frequency filter consisting of passing capacitors and inductive conclusions.

Magnetron is a complex electronic device, to disassemble and repair which is not easy even for a professional. Therefore, making sure that it is the magnetron that does not work, it is best to use the services of the service that has prepared employees, as well as the necessary tools and spare parts.

Types of high.voltage converters

Elements of the converter installed in the microwave tank:

U = 220 V enters the primary winding. The glow thread is fed from secondary ones. The first of the two secondary windings is made of a large section wire. U at the output. approximately 3 in. At the output of the second winding. alternating high u = 4 kV.

In microwaves of different brands, transforming devices of various production were used. Converters do not look the same and have different characteristics. They differ:

• power;
• output voltage of secondary windings;
• the number of turns in the coils and the cross.section of the wire;
• dimensions;
• method of consolidation.

The secondary coil, like one of the conclusions of the emitter, is closed to the case.

Dismantling of a microwave oven on your own

If the above reasons have not been confirmed, then you need to disassemble the device to search for problems. Before that, you must turn off the stove from the network and wait a couple of minutes.

What is worth to find when searching for breakdowns? There are several main elements that are often leaving the system:

These elements are directly involved in the operation of the device and mentioned earlier. First you need to check the serviceability of the fuses. Their breakdown is visible immediately, because when combustible, the conductor inside is destroyed. If this does not happen, then it is worth looking for further. For further verification, you need to take a multimeter, because outwardly finding a breakdown on other details is extremely difficult. To check the capacitor, you need to switch the device into an ohmmeter mode, and then connect to the part. If there is no resistance, then the part must be replaced.

High.voltage diode cannot be checked by a tester. It is recommended to replace it with a breakdown of other parts, because often there is a blow to it. Its check can be carried out with a slightly different method. by connecting to the network on the way to the light bulb. If the light bulb burns weakly or flashes, then the part is in good. If it burns brightly or does not turn on at all, then the diode must be replaced. It is important to observe safety precautions, because this element is able to hold a charge for a long time. It will take several minutes to discharge a serviceable transformer, and with a breakdown of the discharge resistor. much longer. It is worth discharge it about the case or not to touch it at all if there is no experience with such a technique. Next, the transformer windings are checked.

How to check the microwave transformer:

It is necessary to remove the terminals and alternately check the conclusions of the device by an ohmmeter. First, the primary winding is checked, for which the norm varies from 2 to 4.5 Ohms. For the secondary winding, the limits are 140 and 350 Ohms. It is also worth checking the glow winding, connecting the terminals leading to the magnetron to the multimeter. The norm here varies from 3.5 to 8 Ohms. All previous tests did not give a result, the problem may be in the magnetron.

To check the magnetron, just connect the tester to its power terminals. The tester switches to ohmmeter mode. If the resistance is 2-3 ohms, then this means a breakdown of the device. The same situation, if the tester appears infinity. In both cases, the device must be replaced.

Signs and causes of a transformer malfunction

The occurrence of problems in the transformer can be determined by the following signs:

• Sunny can be seen and the smell of burning isolation is clearly felt;
• When working, the microwave makes increased noise;
• Products do not warm up.

In many cases, the malfunctions are caused by voltage surges in the network: a wire break may occur, or a short circuit can occur. You can do without checking if traces of melting are clearly visible and smells of burning. Then the transformer replacement is required.

Advice! Mainly due to differences on the network, reel coils suffer. It is there that you should look for the causes of malfunctions.

The steel plates of which the converter frame consists of should be glued together. If a stratification occurs, then the transformer begins to make noise when working. In this state of things, you need to buy a new device with similar power characteristics and replace the faulty.

Checking the performance of the device

Check the high.voltage transformer if, for no apparent reason, the microwave stopped performing the functions of warming up. Or warms, but unsatisfactory. To do this, you will have to arm yourself with a multimeter and refresh the safety rules when working with electrical equipment in memory.

Safety regulations

When going to check such an unsafe device as a transformer, in addition to the tester, prepare a set of necessary tools. Additionally you need screwdrivers with different tips, pliers and an ohmmeter.

Important! All devices for working with a transformer must have handles with reliable insulation.

• Disconnect the stove from the network;
• disassemble the device, starting from the removal of the casing, for which all the screws should be unscrewed on it;
• Be sure to discharge the capacitor through a simple closure of its contacts, for which you can use the pliers;
• remove the terminals from the transformer and check the coils;
• Continue the search for faults in other places if the coil checks have not revealed the problem;
• replace the transformer if cliffs and short circuits are found;
• Perform the return installation and check the operability of the furnace.

If, after all the above manipulations, the microwave oven still does not perform its functions, then it is necessary to make a voltage check.

Methods of verification

The master determines the possibility and feasibility of using one of the verification options on the basis of his qualifications in this area. To be guided by common sense. And if there is even the slightest share of doubts about their own abilities, then the work must be entrusted to the professional.

Indications corresponding to one determine the break in the coil. And the values ​​that differ from the tabular indicate a possible short circuit.

Advice! By closing the tester probes among themselves, you can receive an indication of your own error of the device. This value must be added to the tabular for more accurate results.

Important! This operation belongs to the category of dangerous ones, so it is undesirable to carry out it.

To diagnose this method, a multimeter is required that can measure an alternating voltage of 2,000 volts or more.

An increase in the temperature of the transformer during passive inclusion in the network indicates a closure in the coils. But if heating occurs only when the emitter is working, then the reason must be sought in another place.

What are the malfunctions?

Check the transformer in two cases: when the stove works poorly and when it doesn’t work at all. Suspend the malfunction of this particular element on the following signs:

• The microwave oven unusually loudly makes noise;
• The food placed in the camera does not heat up or heat up slightly;
• during work it smells of burning insulation, the technique smokes.

If at least one of the listed symptoms appears, it is better not to turn on the device. until the problem is eliminated. The inclusion of a faulty stove can lead to aggravation of the breakdown.

One of the most common reasons for the failure of electrical equipment is the jumps in the mains. If there is a suspicion that the device is faulty due to drops on the network, urgent repair is needed. However, it is possible that a factory marriage will be discovered during the repair work.

Causes of malfunctions

The converter fails most often because of:

• Cross of the wire. The wire of one of the windings may break.
• Short circuit in windings. This can happen in one coil or in both.
• Cliff or closure in the coil of the magnetron.

The converter magnetic circuit is assembled from steel plates. If the plates are exfoliated, the device will make noise. You need to find out the power of the transformer and replace it. Such global breakdowns can be easily determined by eye, but they do not happen often. The overwhelming number of problems are nevertheless provoked by coils.

Causes of malfunctions

The converter fails most often because of:

• Cross of the wire. The wire of one of the windings may break.
• Short circuit in windings. This can happen in one coil or in both.
• Cliff or closure in the coil of the magnetron.

The converter magnetic circuit is assembled from steel plates. If the plates are exfoliated, the device will make noise. You need to find out the power of the transformer and replace it. Such global breakdowns can be easily determined by eye, but they do not happen often. The overwhelming number of problems are nevertheless provoked by coils.

The procedure for verification

To check the serviceability of a high.voltage converter, you need to arm yourself with a multimeter, you will also need:

• screwdrivers with different tips;
• pliers;
• Ommeter.

• Turn off the device. get a fork from a socket;
• unscrew the screws and remove the casing;
• discharge the capacitor;
• remove terminals from the transformer;
• Check the coil by the coil by the tester. if there are no deviations, put back;
• If damage is detected, the wire broke or the closing occurred, the device is changed;
• Collect the oven and check its functioning.

If the device still does not work after the measures taken, you should continue searching for faults or check the device under voltage.

The transformer with traces of melted insulation and the smell of Gary does not need to further check: it is broken and cannot be repaired.

Important! To check the transformer, you have to disassemble the microwave oven-you can do this only when it is turned off from the mains.

The high.voltage capacitor easily retains a huge electric loader, so before measurements it must be discharged. How to achieve this? Just close his contacts with each other. this can be done, for example, by pliers.

Checking the transformer using a multimeter

In modern technology, transformers use quite often. These devices are used to increase or decrease the parameters of alternating electric current.

The transformer consists of input and several (or at least one) output windings on a magnetic core. These are its main components. It happens that the device fails and there is a need for its repair or replacement.

To establish whether the transformer is working, you can use a home multimeter on your own. So, how to check the transformer by a multimeter?

Fundamentals and principle of work

The transformer itself belongs to elementary devices, and the principle of its action is based on a bilateral transformation of the excited magnetic field. What is characteristic, the magnetic field can be induced exclusively using alternating current. If you have to work with the constant, first it must be transformed.

The primary winding is wound on the core of the device, on which an external alternating voltage is supplied with certain characteristics. Next, it goes or several secondary windings in which alternating voltage is induced. The transmission ratio depends on the difference in the number of turns and the properties of the core.

Varieties

Today on the market you can find many varieties of a transformer. A variety of materials can be used depending on the design chosen by the manufacturer. As for the form, it is selected exclusively from the convenience of placing the device in the electrical appliance case.

Only the configuration and material of the core affects the calculated power. In this case, the direction of the turns does not affect anything. the windings are wound both towards and from each other.

The only exception is the identical choice of the direction if several secondary windings are used.

To check such a device, there is enough ordinary multimeter, which will be used as a test tester of current transformers. No special devices are required.

The procedure for verification

Checking the transformer begins with the definition of windings. You can do this by marking on the device.

The numbers of the conclusions, as well as the designations of their type, must be indicated, which allows you to establish more information on reference books. In some cases, there are even explanatory drawings.

If the transformer is installed in some kind of electronic device, then the principal electronic circuit of this device, as well as a detailed specification, will be able to clarify the situation.

So, when all the conclusions are defined, the tester is coming. With it, you can install the two most frequent malfunctions. a closure (on the housing or adjacent winding) and a break in the winding. In the latter case, in the ohmmeter mode (resistance measurements), all windings are called back in turn. If any of the measurements shows a unit, that is, infinite resistance, then there is a cliff.

There is an important nuance here. It is better to check on an analogue device, since the digital can give out distorted readings due to high induction, which is especially characteristic of windings with a large number of turns.

When the closure is being checked to the case, one of the probes is connected to the winding, while the seconds of all other windings and the body itself are called the second. To check the latter, you will need to first clean the place of contact from varnish and paint.

Determination of interval circuit

Another frequent breakdown of transformers is an interval circuit. Checking the pulse transformer for such a malfunction with only a multimeter alone is almost unrealistic. However, if you attract smell, attentiveness and acute vision, the task may well be solved.

A little theory. The wire on the transformer is isolated exclusively by its own varnish coating. If there is a breakdown of isolation, the resistance to the intercourse remains with neighboring turns, as a result of which the place of contact heats up. That is why the first thing you should carefully inspect the device for the appearance of paving, blackening, burnt paper, bloating and smell of Gary.

Next, we try to determine the type of transformer. As soon as this turns out, according to specialized reference books, you can see the resistance of its windings. Next, switch the tester into the megommeter mode and begin to measure the insulation resistance of the windings. In this case, the tester of pulsed transformers is a regular multimeter.

If the resistance of the windings for one reason or another is not indicated, other data must be given in the directory: the type and cross section of the wire, as well as the number of turns. With their help, you can calculate the desired indicator yourself.

Checking of household lowering devices

It should be noted the moment of verification by the tester-multimeter of classic decrease transformers. You can find them in almost all power supplies, which lower the incoming voltage from 220 volts to the 5-30 volts entering.

First of all, the primary winding is checked, on which a voltage of 220 volts is supplied. Signs of a primary winding malfunction:

In this case, the experiment should immediately stop.

If everything is fine, you can proceed to measurement in secondary windings. You can only touch them with tester contacts (probes). If the results obtained are less than the control at least 20%, then the winding is faulty.

Unfortunately, such a current block can be tested only in cases where there is a completely similar and guaranteed working unit, since it is precisely the control data that will be collected. It should also be remembered that when working with indicators of about 10 Ohms, some testers can distort the results.

Idle current measurement

If all tests showed that the transformer is completely serviceable, it will not be superfluous to conduct another diagnosis. on the current of the idle transformer. Most often it equals 0.1-0.15 from the nominal indicator, that is, the current under load.

To conduct the check, the measuring device is switched to ammeter mode. An important point! The multimeter to the test transformer should be connected at the closed closed.

Microwave oven renovation. The microwave scheme

In this topic, you will get acquainted with the device of the microwave, with its electrical circuit, as well as, with the details of the microwave. According to photographs, you can get additional information related to the verification of the magnetron and the power transformer.

Repair of the microwave-with-hands

To deal with this question: “How to repair a microwave oven,” you need to understand what the principle of operation of this type of household appliance is based on what is based on. The causes of the malfunction can be diverse, including the simplest reasons:

• rupture of wire along the length of the network cord;
• malfunction of an electric fork;
• inconsistency in the detachable connection of the fork with the outlet spit in the connection

Scheme of the microwave oven

The circuit of the microwave oven consists of the following elements:

• power transformer;
• secondary winding;
• safety diode;
• high.voltage diode;
• fragmentary winding;
• capacitor;
• resistance;
• magnetron.

High.voltage transformer of the microwave oven

The power transformer of the microwave oven is an increasing transformer of 2 kV power. 850 W., necessary for converting the electrical energy of alternating current of one voltage into the electrical energy of another voltage at a constant frequency.

How the microwave magnetron works

The magnetron consisting in the diagram consists of the following elements:

• Antenna emitter;
• resonant cavities resonators;
• the anode of the wall of the camera;
• Cathode metal thread;
• insulator;
• braid;
• flange;
• magnet;
• frame;
• radiator;
• diet conclusions;
• filter;
• ferrite rod;
• coil;
• lid;
• ligaments;
• Communication loop.

The main elements of the Magnetron of the microwave, this is:

What is the microwave oven

Having sorted out the device of the microwave, it will not be difficult to fix it. The reason for the breakdown can be any listed elements, checking electrical circuits and elements- is carried out in a passive way without connecting to an external source.

Malfunction of the microwave oven LG

Dismantling of the microwave oven LG photo is practically no different from disassembling other modifications of such furnaces.

The upper cladding is initially removed and then diagnostics is carried out both for individual sections of the electric circuit and for individual elements consisting in the electrical circuit of the microwave oven.

With a visual examination of the microwave oven for this example, the photo shows that in the inner cavity where the food is directly heated, there is a burning from the side of the wall of the magnetron.

That is, the waveguide of the magnetron of the photograph on the right as a result of a certain life was heated and as a result of the deformation of the waveguide plate,-there was a closing on the case of the microwave oven.

The reasons for such a malfunction of the magnetron of the microwave oven, in my opinion, may be the following:

Checking the magnetron of the microwave oven

The diagnostic can determine whether the magnetron is suitable for further operation or whether it should be replaced.

The photo on the right photo shows that when measuring resistance, this indicator is zero value or in other words, this will mean “short circuit mode” mode.

Checking the microwave transformer

In two photographs presented photos, the image of the power transformer of the microwave oven is given.

Let’s say we need to determine whether the transformer is suitable for its further operation? Accordingly, here it is also necessary to measure the resistance:

To diagnose, it is necessary to disconnect the contact connections of the wires from the primary and secondary windings of the transformer.

The measurement of the resistance of the primary winding of the transformer photo can be done in two ways:

The display of the device when measuring the resistance of the primary winding shows the zero value and here it becomes clear to us that the primary winding has become unusable closed.

When measuring the resistance of the secondary winding of the photo transformer, it is clearly seen that this resistance indicator in value is also not permissible.

I would believe that the cause of such a malfunction of the magnetron was the initial malfunction of the power transformer of the microwave oven.

So, in a visual example, we examined the two main causes of the malfunction of the microwave:

It remains only for the latter, either replace two unsuitable elements of the microwave in the diagram, or leave the microwave for spare parts and purchase a new.

High.voltage transformer in the electrical circuit of the furnace

The described device contains in its structure the frame, magnetic wire, the winding of the primary purpose in one quantity, and the winding of the secondary purpose in the amount of two. The secondary type winding is necessary for transmitting to the magnetron chain, in particular on an anode fishing line for a trimmer and a thread of incandescent, nutrition. The incandescent thread always contains the wire more thickened, because the voltage passes through it, which at the exit gives almost three volts. this is a high.voltage wire. The anode fishing line for a trimmer, a secondary type winding, involves the production of voltage of a variable direction, a maximum of which 4 kV. The primary winding is always powered by a household electrical network, so it works in standard household indicators of 220 volts.

Sometimes there is a difficulty with constructions of various stove brands, because a different manufacturer offers consumer goods of different types, size or variations of fasteners. The power class, the degree of voltage of the output in the winding of the secondary type may also differ. The thickness and resistance of the wire is often different, therefore the amount of material changes.

It is important to remember that at one exit of the magnetron there will be a closure with a winding of the secondary sample, it also closes on the case.

What is contained in the microwave and its scheme, in addition to the transformer:

• diode and capacitor of high voltage voltage;
• Aircraft circuit breakers of the end type;
• magnetron with a fuse;
• block for controlling the heating process;
• platform electric motors, thanks to which circular movement occurs when starting the program and fan.

The stoves of more expensive production lines offer users impulse.purpose blocks instead of a transformer. They are characterized by slight weight, but have a more complex design device.

Possible malfunctions of the transformer and their signs

It should be remembered that without much need, there is no need to conduct diagnostics of the technique, it should only be consulted in two cases. when the household device began to work not so efficiently, unnecessary noise appeared or it does not respond to the launch in the state included in the energy consumption network.

What symptoms will be observed when the transforming block fails:

• After choosing the program and pressing the start button, the stove is buzzing or noisy, which was unusual for it earlier.
• Food is not heated evenly or did not at all reach the necessary temperature.
• You feel the characteristic burning smell of insulating winding.

If you notice the above signs, it is not recommended to use the furnace more. Quickly turn off the device from the power supply network, because otherwise, the consequences can be catastrophic.

Often breakdowns can occur due to an uneven abolishing flow of current into a household power supply. This reason cannot be denied or foreseen, so you should tune in to the repair work. In addition, during this process, you can notice a marriage at your device, which was allowed in production.

Possible symptoms can be detected due to the list of causes:

• Frequent cases are a rupture of wires of the secondary or primary winding of the wire, options are possible when both windings are damaged at once, but this case is quite rare.
• Short type of short type or in a chain on the line between the exit from this winding and the entrance to another, and perhaps both windings were closed at the same time.
• Magnetron could give a cliff or closing in a gloss winding chain.

The magnetic wire is a transformer block that consists of electrical steel sheets. Deviation of these electrical sheets can provoke alien extra noise during the start of the program, if the reason is precisely in this, then it will have to be fully replaced by the transformer. The user perceives and calculates this malfunction even visually, and in percentage a breakdown of this type is very rare.

Check the transformer yourself

You can identify its performance in two ways. safe and under voltage. About this below.

Safe diagnostics: how to check the transformer of the microwave multimeter

Safe research is performed using a tester (multimeter). The essence of the study is a search for any malfunctions. The sequence of actions is as follows:

• The device is set for measurement, setting the necessary limits of measurements.
• After that, check the resistance of the coils. primary and secondary.

Important! Before the measurements, the converter must be extracted from the body. If the number “1” appears on the tester panel, there was a gap

If there is a closed circuit on the first coil on the indicator, there should be a value of about 4. 4.5 ohms, on a fragment coil of 3.5–8 Ohms, on a high.voltage 140–350 Ohm. The multimeter is tuned to the measurement range within 200 Ohms. During measurements, the results should not go beyond the indicated limits

If the number “1” appears on the tester panel, there was a gap. If there is a closed circuit on the first coil on the indicator, there should be a value of about 4. 4.5 ohms, on a fragment coil of 3.5–8 Ohms, on a high.voltage 140–350 Ohm. The multimeter is tuned to the measurement range within 200 Ohms. During measurements, the results should not go beyond the indicated limits.

Important! If the measurements have gone beyond the indicated limits, then most likely there was a short circuit between the turns of the winding. It is advisable to take into account the error of the measuring device

In order to check the condition of the device, there is no need to give the stove to the service center. If the user has knowledge of the basics of electrical engineering, then he will be able to test voltage parameters

It is advisable to take into account the error of the measuring device. In order to check the condition of the device, there is no need to give the stove to the service center. If the user has knowledge of the basics of electrical engineering, then he will be able to test voltage parameters.

Checking under voltage

If the closure is carried out, but the product still does not work as usual, then it makes sense to determine the condition of the secondary throttle.

Attention! This is a dangerous process, and when performing work, it is necessary to observe security measures. The algorithm for checking the device under the current looks as follows:

The algorithm for checking the device under the current looks as follows:

The voltage on the gloss coil should lie within 3 square meters, on high.voltage. 2 kV.

Reverse check

This method of checking the transformer is probably the easiest. 220 V is fed to the secondary winding, 24 in the primary will be removed. In the event that it is 12 V for the primary winding, then on the secondary potential it will reach 109 in.

If the device is heated in idle mode, then, most likely, there was a closing between the turns of the winding. If it heats up during operation, and when disconnected, it stops heating, then it is necessary to look for problems further.

How to check the transformer in the microwave

The transformer for the microwave is an important link in the chain generating microwave radiation. This is a voltage converter to the size supplied to the input of the magnetron. A high.voltage converter often causes a breakdown of a microwave oven.

Checking the transformer for performance is an obligatory point in the list of technical diagnostics measures to find out the causes of the malfunction. Since we are talking about high stresses, independent intervention is possible only if all safety measures are observed.

Where to get high voltage?

Food in microwaves is warming up due to the work of ultra-frequency waves. Generates microwaves of a special emitter. magnetron. To work in the specified characteristics, he needs high voltage. 2,000 in. This is almost an order of magnitude higher than what the household power supply gives (220 V).

Where are the kilo of the kilo? They are created at the output of the secondary winding of the high.voltage converter.

Important! SCHCH, even disconnected from the mains, can hit the electric current (U up to 5,000 V).

Types of high.voltage converters

Elements of the converter installed in the microwave tank:

U = 220 V enters the primary winding. The glow thread is fed from secondary ones. The first of the two secondary windings is made of a large section wire. U at the output. approximately 3 in. At the output of the second winding. alternating high u = 4 kV.

In microwaves of different brands, transforming devices of various production were used. Converters do not look the same and have different characteristics. They differ:

• power;
• output voltage of secondary windings;
• the number of turns in the coils and the cross.section of the wire;
• dimensions;
• method of consolidation.

The secondary coil, like one of the conclusions of the emitter, is closed to the case.

The circuit of the electric circuit

In the electrical circuit, microwaves, in addition to the converter, are present:

• diode;
• high.voltage capacitor;
• magnetron;
• fuse;
• The electric motor. one or two (for rotation of the pallet, if it is provided for the design, and for the fan);
• Control block.

In expensive microwaves, instead of a converter, a pulse block is used, which has a more complex device, but weighs less.

What are the malfunctions?

Check the transformer in two cases: when the stove works poorly and when it doesn’t work at all. Suspend the malfunction of this particular element on the following signs:

• The microwave oven unusually loudly makes noise;
• The food placed in the camera does not heat up or heat up slightly;
• during work it smells of burning insulation, the technique smokes.

If at least one of the listed symptoms appears, it is better not to turn on the device. until the problem is eliminated. The inclusion of a faulty stove can lead to aggravation of the breakdown.

One of the most common reasons for the failure of electrical equipment is the jumps in the mains. If there is a suspicion that the device is faulty due to drops on the network, urgent repair is needed. However, it is possible that a factory marriage will be discovered during the repair work.

Causes of malfunctions

The converter fails most often because of:

• Cross of the wire. The wire of one of the windings may break.
• Short circuit in windings. This can happen in one coil or in both.
• Cliff or closure in the coil of the magnetron.

The converter magnetic circuit is assembled from steel plates. If the plates are exfoliated, the device will make noise. You need to find out the power of the transformer and replace it. Such global breakdowns can be easily determined by eye, but they do not happen often. The overwhelming number of problems are nevertheless provoked by coils.

The procedure for verification

To check the serviceability of a high.voltage converter, you need to arm yourself with a multimeter, you will also need:

• screwdrivers with different tips;
• pliers;
• Ommeter.

• Turn off the device. get a fork from a socket;
• unscrew the screws and remove the casing;
• discharge the capacitor;
• remove terminals from the transformer;
• Check the coil by the coil by the tester. if there are no deviations, put back;
• If damage is detected, the wire broke or the closing occurred, the device is changed;
• Collect the oven and check its functioning.

If the device still does not work after the measures taken, you should continue searching for faults or check the device under voltage.

The transformer with traces of melted insulation and the smell of Gary does not need to further check: it is broken and cannot be repaired.

Important! To check the transformer, you have to disassemble the microwave oven-you can do this only when it is turned off from the mains.

The high.voltage capacitor easily retains a huge electric loader, so before measurements it must be discharged. How to achieve this? Just close his contacts with each other. this can be done, for example, by pliers.

Diagnostic options

Consider the common options for finding causes of breakdown.

Safe check

The safest study is carried out by a tester and is to study the coils for damage. Procedure:

• The multimeter is tuned to the desired limits and determined with its help the resistance of all windings. primary and two secondary. The study is done on the removed transformer.
• If a unit is displayed on the tester, then there is a cliff.
• With a closed circuit on the primary coil, the value will appear in the range of 2–4.5 Ohms (the tester is set at 200 Ohms). On the Opalnaya. 3.5–8 Ohms, on the high.voltage secondary (2,000 Ohms). 140–350 Ohms.