DIY voltage regulator repair

In detail: DIY repair of a relay voltage stabilizer from a real master for the site my.housecope.com.

In many apartments, especially in rural areas, a stabilizer must be installed in the house.
Some owners use it to work especially "sensitive" equipment, gas boilers, refrigerators and other similar household appliances.

Some more caring owners install the stabilizer “for the whole house”, such stabilizers, as a rule, have not small dimensions and weight and their power starts from 7-10 kW and more.

It is about such stabilizers that we will talk in this article, but actually about their repair and troubleshooting, since every technique they fail.
In this article, we will consider the repair of a relay stabilizer of the famous Chinese company "Forte - ACDR - 10000" for 10 kW.

But before proceeding with the repair, let's understand the nature of its device.
The relay stabilizer consists of several parts assembled into a single system:

Automatic transformer - the heaviest part of it is a large iron core with several windings connected according to the principle of an autotransformer. Several ends of a thick copper wire leaving the transformer are switched using a relay, the number of which depends on the windings and switching stages.

Control elements - power elements with the help of which the switching of the windings and the start with a delay are carried out. In relay stabilizers, the role of such elements is played by relays, but in “more expensive models”, such elements can be semiconductor elements - triacs, which have a much longer service life for “switching”.

Video (click to play).

Control block - the main board of the device with a microprocessor installed on it, with the corresponding firmware, which is programmed to switch and control power elements (relays). At predetermined voltage levels, the corresponding autotransformer windings are switched. In cases where this is not possible, due to a breakdown, an “error” is issued and the stabilizer restarts or shuts down. There is also a switch-on delay circuit (for example 120 seconds).

Voltage indication and measurement unit - a board, as a rule, installed on the front panel (cover) of the stabilizer. In the same place, “digital indicators” or a display are installed on it.
In addition to them, control elements can be installed, for example, the inclusion of a "delay".

The stabilizer constantly compares the input voltage level with the nominal one and “decides” to either add or reduce a certain amount of volts to the “home” power grid. Such solutions are carried out by connecting or disconnecting (switching) the necessary windings, in this case using a relay.

All stabilizers have a protection system that checks the input and output voltages, current, temperature for compliance with the rated value and operating conditions. Each stabilizer has its own defense mechanisms, but several main ones can be distinguished:

Stabilization limits (input and output voltage)

Output to input voltage ratio

Excess load current (overload)

Overheating of the transformer, excess temperature inside the device

Inability to “switch” the winding (in case of failure of the controls)

The most common cause of breakage such stabilizers are relays that switch transformer windings.As a result of multiple switchings, the relay contacts can burn out, jam, or the coil itself can burn out.

If the output voltage disappears or an “error” indication appears, all relays must be checked. First, having examined externally and if no visible damage is noticeable, then disassemble the case of each relay.
It will immediately become noticeable which contacts are how much worn out, and where are completely burnt out.

In this stabilizer, the malfunction manifested itself in the form shutdown of the stabilizer by "mistake" which was accompanied by a sound indication. It did not always turn off, but only when the voltage was greatly reduced, but within the aisles of the stabilization rate. - somewhere around 175 volts. It was disconnected regardless of the load at the output, which clearly swept aside the general overload as the cause. Before turning off, you can hear the relay clicking several times.

As it turned out later, the control unit gave a command to the relay to switch to another winding, but since the windings were not physically switched, an “error” took off and the stabilizer simply turned off.

Having disassembled all the plastic covers of the relay, it was burning detected on two relays, but in one of them the contact pad, which should connect the windings, completely burned out and the “contact” was simply impossible, even though the relay clicked to close the plates.

There could also have happened such a case in which contacts could get stuck to each other and as a result, several transformer windings will be short-circuited. The transformer will start to overheat and if the protection does not work, then one of the autotransformer windings may burn out. By the way, such a danger is inherent not only in relay stabilizers, but also in triac ones.

Very often, in relay stabilizers, transistor switches fail, which in different models of stabilizers can be assembled on different types of transistors. When faulty “amplifiers” were found when ringing the radio elements of the circuit, they must be replaced with the same ones in terms of parameters.

The preventive measure to restore slightly burnt stabilizer relays is quite simple and consists of the following actions:

1.remove the relay cover
2.remove the spring to release the movable contact of the relay
3.Each movable and fixed contact must be cleaned with fine sandpaper
4.wash the contact pads with alcohol
5.after the alcohol has dried, cover with KONTAKT S-61 protective agent

With a stronger and more significant burning of the relay contacts and if it is not possible to replace it, you can proceed as follows: if possible, clean the relay contacts (by the method described above) and swap the relay.
That is, where in the stabilizer there is the most frequently used winding on which the relay constantly burns, put a “new” relay, and put the “tired” relay in place of the relay that has been preserved in good condition, there it will last a long time.

When complete burnout of the relay contact pad, it needs to be replaced with a new one.
But when there is no time to wait for a parcel with a new relay or there is a desire to try to restore the burnt part of the plate on your own, you can do as I did.

In the same size ratios, a piece of copper core was cut out, which was fixed along the entire length of the plate with solder, after tinning the core and the plate itself. But so that the contact point still falls on the copper part, and not on the solder.

In the presence of powerful spot welding, it was better to weld all this for greater reliability in case of possible heating of the plate.
But since in this device the relay was replaced and put in a place where there is no burning, for example, on the lowering part of the winding, then there is nothing to worry about.

In addition to obvious mechanical problems with relays and failure of the “amplifiers” presented in the form of key transistors, there may be other breakdowns already on the control unit board: cold soldering, peeling tracks on the board, burrs at soldering points, balls from solder and contact separation in pin connections - that's just a small thing that can cause the stabilizer to malfunction.

Sometimes there is such a problem as a chaotic display of segments on the display, at the same time, a chaotic switching on of the relay can be observed. A common reason for this behavior is "Cold soldering" a quartz resonator that operates at a frequency of 8 - 16 megahertz, its bad loss leads to improper operation of the microprocessor.
Therefore, it is better to immediately inspect the entire back of the board for poor soldering, burrs or balls of solder, which are often there in view of the fast soldering of the boards by the assemblers who assemble it.

Then you can inspect the board for defects in radioelements. Very often, over time, electrical capacitors swell and fail, it will not be difficult to identify this. They must be replaced with similar ones.
In addition, a cracked terminal block was identified in the stabilizer, which could not provide reliable contact of a powerful power cable. Such a terminal block, due to the impossibility of creating a sufficient tightening of the wire, could heat up and thereby, over time, also aggravate the reliability of the contact.

But after repairing the stabilizer or even at the stage of diagnosing a malfunction, it becomes necessary to check the operation of the device in a different voltage range, both high and low.

In workshops, a LATR or an adjustable-type laboratory autotransformer is used for these purposes. It is connected to the input of the tested stabilizer and already changing the voltage at the input, imitating the drops in the network, they look at the behavior of the stabilizer, whether it can cope with the work within the nominal (passport) voltage limits.

But since I do not have a corresponding regulated autotransformer, we took a slightly different path. A certain “scheme” was assembled:

1. At the input of the stabilizer, a light bulb of about 60 watts was connected in series to the phase, the power of the light bulb is selected experimentally.

2. At the output, as a load, a regular mains screwdriver or drill (400 - 1000 Watts) with a button for smooth speed control was connected.

During the operation of the screwdriver at minimum speed, the light that is turned on at the input sequentially does not light up. At the same time, the stabilizer is up and running without any problems.
We begin to smoothly increase the speed of the screwdriver, while the light bulb shines brighter and brighter.
The more intense the brightness of the light bulb, the more the voltage sags at the input of the stabilizer, which is naturally seen on the display indication. In addition, when the voltage at the input decreases, you can hear how the transformer windings switch and the relay clicks.
In this non-tricky way, you can track whether the stabilizer is working correctly, provided that your home network has a normal voltage (220 - 240 volts).

As you can see, you can also repair the voltage stabilizer at home. Well, or at least you can disassemble and identify the broken unit and estimate the cost of work to restore or replace it. It is assumed that the person who starts repairing the stabilizer will have basic knowledge of electricity and electronics and will have a minimum set of tools, a soldering iron, a multimeter and a small tool.
Care should be taken when working with voltage when diagnosing and checking operation. All other repair and replacement work is carried out in a de-energized state.

Graphic display of the main operating modes of voltage stabilizers

In one of the previous articles, the main types of voltage stabilizers were described, as well as instructions on how to connect them to the network with your own hands. This material introduces the main malfunctions of voltage stabilization devices and the possibility of their self-repair.

It must be remembered that a stabilizer of any type is a complex electrical or electromechanical device with many components inside, therefore, in order to repair it with your own hands, you must have a sufficiently deep knowledge of radio engineering. Repairing a voltage regulator also requires appropriate measuring equipment and tools.

Sophisticated stabilizer design

All voltage stabilization devices have a protection system that checks the input and output parameters for compliance with the rated value and operating conditions. Each stabilizer has its own protective complex, but several common ones can be distinguished. parameters, going beyond which will not allow the stabilizer to work:

Rated input voltage (stabilization limits);
Output voltage matching;
Excess load current;
Temperature range of components;
Various signals from indoor units.

The list of control parameters of the stabilizers specified in the technical characteristics

It is necessary to check whether there is a short circuit in the load, the input voltage, the temperature conditions of operation and study the meaning of the error codes displayed on the displays.

The most difficult thing is to find a breakdown in the stabilizer on triac keys, which are controlled by complex electronics. For repairs, you must have a diagram of the device, measuring instruments, including an oscilloscope. According to the given oscillograms at the control points, a malfunction is found in the structural module of the stabilizer, after which it is necessary to check each radio component in the defective unit.

The main nodes of the triac stabilizer

In relay stabilizers, the most common cause of failure is the relay that switches the transformer windings. Due to frequent switching, the relay contacts can burn out, jam, or the coil itself can burn out. If the output voltage fails or an error message appears, check all relays.

Power switches of the relay stabilizer

For a master unfamiliar with electronics, it will be easiest to fix an electromechanical (servo) stabilizer - its operation and reaction to voltage changes can be seen with the naked eye immediately after removing the protective casing. Due to the relative simplicity of the design and high stabilization accuracy, these stabilizers are very common - the most popular brands are Luxeon, Rucelf, Resanta.

Resant stabilizer, power 5 kW

If the stabilizer transformer began to warm up without a noticeable load, then a short circuit, called interturn, may have occurred between the turns. But, given the specifics of the operation of these devices, in which the terminals of the autotransformer or the secondary winding of the transformer are switched all the time in order to adjust the output voltage to the required value, we can conclude that the short circuit is somewhere in the switches.

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Switching unit for relay stabilizer

In relay stabilizers (SVEN, Luxeon, Resanta) one of the relays can jam, and several turns of the transformer will be short-circuited... A similar situation can arise in thyristor (triac) stabilizers - one of the keys may fail and will "short" the output windings. The short-circuit voltage between turns, even with an adjustment step of 1-2V, will be enough to overheat the transformer.

Switching unit of the stabilizer on triacs

It is necessary to check the triac keys to exclude this breakdown.The thyristor or triac is checked by a tester - between the control electrode and the cathode, the resistance during forward and reverse measurements should be the same, and between the anode and cathode, it should tend to infinity. This check does not always guarantee reliability, therefore, to guarantee it is necessary to assemble a small measuring circuit, as shown in the video:

In servo-driven stabilizers, the windings do not switch, but adjacent turns can also be closed due to a mixture of soot, dust and graphite sawdust clogged in the space between the turns. Therefore, servo-driven stabilizers such as Resanta and others require periodic preventive cleaning of contaminated contact pads.

Many users have noticed that the rate of wear and contamination of the contacts of servo stabilizers depends on the operating environment, in particular, on dust and moisture. Therefore, the craftsmen came up with a way to modify Resant's stabilizers by installing a fan from a computer processor (cooler) opposite the most frequently used autotransformer sector.

Miniature fan for servo stabilizer modification

A constantly running fan prevents dust from settling on the contact pads, preventing contamination and wear by removing abrasive particles from the working area. In addition to cleaning the contact surfaces, the fan installed in the Resant stabilizer will also contribute to better cooling of the autotransformer.

Repair of stabilizers with a servo drive, such as Resanta, should begin with an inspection of the working contact area of the autotransformer.

Carefully inspect the most worn areas of the contact turns

If the Resant's stabilizer was stored in a humid environment after a long time of operation, then the exposed unprotected copper contact pads could oxidize, which prevents the contact slider from contacting. Dust accumulated during downtime due to sparking can be flammable. Briefly about the prevention of electromechanical stabilizers and a demonstration of the servo drive in the video:

It is best to remove the pin slider from the servo shaft first. After that, you should use fine sandpaper to clean the contact pads to a metallic sheen. It is better to clean the auto-transformer contacts with a regular eraser. Then you need to carefully remove the accumulated sawdust and abrasive particles with a brush. Image - DIY repair of a relay voltage stabilizer

The device of the contact assembly of the servo stabilizer

The next step in repairing the servo stabilizer will be inspection, cleaning and possible replacement of the contact graphite brush. During operation, this brush heats up due to the currents flowing through it. But even more heating occurs due to poor contact between the brush and the contact plates of the autotransformer. Due to the increased heating and arcing during the movement of the slider, the brush burns out even more, thereby contaminating the contact pads and the gaps between them.

Severe contamination of the contacting turns of the autotransformer

Thus, the acceleration of pollution is gaining an avalanche-like character, which leads to rapid wear of the autotransformer contacts and burnout of the contact brush, after which the stabilizer will stop supplying voltage. Depending on the protection system in the servo-driven stabilization devices from the Resanta company, or from other manufacturers, in the event of a break in the output voltage, the protective automatics must be triggered.

Contactor - power element of protective automation

That is why it is so important prevention servo stabilizers. Often, Resant's repair ends with cleaning the contacts and replacing the contact brush. But, sometimes in servo stabilizers the servo itself fails.Servo failure can be caused by wear on the gearbox, burned out motor, or lack of voltage. Having taken out the motor together with the gearbox, it is necessary to check the mechanism by turning the shaft.

The electronic control board of any type of stabilizer contains many components, including microcircuits, which cannot be tested without special equipment. But it's worth it carefully inspect the board itself and check the components on it for traces of high temperature.Sophisticated electronic circuit board of the relay stabilizerOverheated resistors are the first to "catch the eye" and sometimes carbonize to such a state that it is impossible to recognize their markings - you will have to study the stabilizer circuit. Overheating of the resistors indicates a breakdown in other elements of the circuit - most often in power transistor switches. A close examination of the transistors can reveal blackening from overheating, and even mechanical cracks. Image - DIY repair of a relay voltage stabilizer

An example of a relatively simple relay stabilizer circuit

The cause of a malfunction of any circuit can be a breakdown in the capacitor. Very often electrolytic capacitors swell, which is why they differ significantly in shape from other capacitors. But the breakdown of a capacitor can not always be determined by its swelling - the electrolyte inside can dry out, from which it will lose its electrical conductivity.

An illustrative example of a blowing capacitor

On the board itself, traces of the impact of freelance overcurrents can also be seen - some tracks may burn, and the contacts may be soldered off, or close together due to the spreading molten solder heated by large currents. In addition, traces of strong heating of parts may remain on the board - from a change in shade to charring of the PCB.

An example of a burned-out track on the board

Visual inspection of the defective module can tell the technician in which direction to diagnose. But, as a rule, the repair of electronic boards of stabilizers is not limited to replacing clearly damaged parts and requires additional checking of various components using special equipment. Therefore, if the continuity of the power transistors and other elements did not reveal the cause of the breakdown, it is better to take the electronic board to the workshop.

Resanta voltage stabilizers can be found in many apartments in our country, which is understandable. This is due to the fact that such units make it possible to normalize the operation of all electrical appliances that are present at home. In other words, they allow you to save quite expensive equipment in the event of an overload in the network, or in case of voltage surges, thereby significantly extending the operational life of all electrical equipment.However, the operation of the voltage stabilizer also carries the risk of certain breakdowns, the only way out of which is timely repair.

There may be several reasons for this - from improper operation to natural causes of breakdown, i.e. long service life.To avoid this, you must exactly follow the instructions that come with the kit, which allows you to significantly extend the service life of the unit in the correct mode of operation. If, nevertheless, a breakdown did happen, then you need to know what methods you need to properly carry out repairs with your own hands, so as not to further aggravate the situation. In this article, we will look at the main malfunctions, as well as ways to eliminate them in a timely manner.This video shows the Resant's stabilizer with a malfunction

The constructive structure of the Resant voltage stabilizer is as follows:

automatic transformer;
the electronic unit;
voltmeter;
a control that is responsible for starting and disconnecting some windings.

This manufacturer produces many different types of stabilizers, therefore, these organs for connecting the windings will differ. We will talk about all these nuances a little later, during the consideration of the repair procedure.

In this design, the decisive factor is the electronic unit, which carries out the general control of the entire system of the unit. He is responsible for the operation of the voltmeter, and also receives information about the power of the input voltage. Then, the block compares the obtained values with the optimal ones, determining the next action, i.e. whether you need to add a few volts or, on the contrary, subtract a certain amount.

Further, along the chain, there is a determination of the necessary windings - which of them need to be started and which ones to be disabled. Then, the electronic unit performs one of these actions, after which all electrical appliances in the apartment receive a stable current.

Of course, the stabilization process itself can be slightly different, depending on the type of device produced.

This difference applies to the types of windings, as well as the methods of starting and disconnecting them. Today, the Resanta company produces two types of these stabilizers:

Electromechanical type.
Relay.

Accordingly, their repair will be somewhat different.

Let's start our consideration with stabilizers of the electromechanical type. In its design there is a servo drive, which starts and turns off the windings in the device.

The servo itself consists of a motor on which an electrical contact (brush) is located. When the armature of this motor moves, accordingly, this brush also rotates, constantly contacting with copper windings. The width of this brush allows for a complete wrap-around of the entire winding, which allows the phase not to be lost.

In order for the brush to move in a given direction with the desired characteristics, an error voltage arises in the device. Then, this voltage value rises. Then it is transmitted to the engine, which makes the armature rotate in the optimal direction. Accordingly, the brush also moves, like the armature, in the same predetermined direction. In this case, direct contact with the windings is carried out.

The error voltage value will be proportional to the value formed by the difference between the real voltage value at the input and the value that should be there. This signal can have one of two polarities, each of which specifies a certain direction of movement. Below is a diagram of a similar voltage regulator:

Regardless of the specific model, the structure of this voltage regulator will be almost the same. They differ among themselves by different power values and individual circuit elements.

All relay stabilizers equalize the current values by surges. This is because the relay starts or turns off the turns located on the second winding. An electromechanical stabilizer performs this process more smoothly than a relay one.

Relay units from Resant connect the turns until they find the right one. All these turns are conventionally divided into subgroups, and from each turn there is an output to which the current flows when the device is started.

The diagram of all relay stabilizers of this brand shows that there are about four relay elements in its design. In some cases, this number can be equal to five (SPN models).

In the case of relay stabilizers, it is the relay that is the most vulnerable point of the entire device. This is due to the fact that it is in a constant operating mode, which significantly increases the risk of failure.

Having considered the principles of operation of both types of voltage stabilizers, we can conclude that it is their main components that are the most frequently breaking system components.We are talking about a servo drive in electromechanical devices, as well as relays in relay ones.

In the first case, the constant movement of the servo leads to periodic friction of the turns of the coil and brush, which leads to excessive overheating of these components. It also causes severe wear and tear and sparks from copper wires.

It is also necessary to bear in mind the fact that the current value periodically changes in the network, which provokes a similar change in the movement of the servo. Such unstable operation can lead to the failure of this device.

Repair of one of the faults is demonstrated in the video.

The repair of the Resant's stabilizer can be roughly divided by the type of breakdown.First, consider the situation when the Resant servo motor has failed. There are two ways out of this problem.:

Buy a new motor, then install it in the device.

Try to repair the damaged one.

While everything is clear with the first case, the second requires detailed consideration. It is important to understand that in case of successful repair work, the restored engine will not be able to work for a long time, i.e. this is a temporary measure.Everything our actions will boil down to the following:

Disconnect the servo motor from the general structure. Then we connect it to a power source with sufficient power.

It is necessary to supply a current of 5 V to the outputs of the motor. The indicator of the current strength must be at least 90 mA.

The implementation of these manipulations will normalize the operation of the stabilizer. Next, you need to connect the motor back to the circuit.

The circuit is quite simple: the input cable is connected to the input terminal, the neutral cable is connected to the neutral terminal. The same manipulations are performed for the output cables. Also, remember to connect the ground wire.Failure of the relay is often leads to breakage of transistors... For example, in the ASN-5000 model, there are D882P transistors. The diagram is shown below: Image - DIY repair of a relay voltage stabilizer

If these transistors fail, then you need to purchase new ones in their place. You can buy them quite freely, because many specialized stores sell equipment and components of the Resanta brand.

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You can also try to repair damaged parts:

First you need to remove the relay cover. Next, we remove the movable contact, freeing it from the spring.
Using sandpaper, we clean off all carbon deposits from the contact. We carry out this manipulation for both contacts - upper and lower.
Then we lubricate the contacts with gasoline, after which we assemble the relay structure.

Another possible problem is the disordered switching on of the display, as well as the switching on of the relay itself. The reason for this may be the XTA1 resonator, which may have an incorrect soldering.

The repair is as follows:

We solder this resonator with a soldering iron.
We clean the leads with sandpaper.
We solder the resonator back.

Specialist's story about Resant's repair

To make diagnostics, we need a LATR device, i.e. laboratory autotransformer of controlled type. We connect the stabilizer to this device, with which you need to change the voltage values. In parallel, we are monitoring the work of the Resant stabilizer.The implementation of repair work, in this case, can be done at home. At the same time, it is assumed that the person performing these manipulations will be well acquainted with such a technique, have the skills of proper soldering and some knowledge in electronics. If a person does not possess this, then it would be more expedient to contact specialists.There are quite a few similar service centers in Moscow and St. Petersburg. In particular, "Demal-Service", located at the address: Moscow, st.1st Vladimirskaya, house 41.In St. Petersburg there is a service center of the company itself, located at the address: st. Chernyakovsky, house 15.Today we will consider a list of basic malfunctions of voltage stabilizers of various types with a description of the causes of occurrence and methods of their repair.Today we will consider a list of basic malfunctions of voltage stabilizers of various types with a description of the causes of occurrence and methods of their repair. After all, not every breakdown of a voltage stabilizer requires service repair, especially after the expiration of the warranty period.About the internal structure and types of stabilizers Of all the varieties of voltage stabilizers, three most common topologies can be distinguished with rather specific conversion principles. Among them, it is impossible to single out the most reliable one, too much depends on the nature of the power supply and the type of load, as well as on the quality factor of the device. In our review, we will consider servo, relay and semiconductor converters, features of their operation and typical malfunctions.In a servo-driven stabilizer, the main functional element is a linear transformer with a multitude of mid-point leads of the secondary, and sometimes the primary winding - from 10 to 40, depending on the accuracy class. The ends of the leads are assembled into a collector comb, along which the collector carriage moves. Depending on the effective voltage on the power line, the stabilizer corrects the position of the carriage, thereby adjusting the number of involved turns and, accordingly, the transformation ratio. At the output of the circuit, a more fine adjustment of the voltage can be carried out, for example, using integrated semiconductor stabilizers.Relay transformers are designed in a similar way. The number of transformer terminals is smaller; instead of smooth regulation, the fine tuning is achieved by recombination of the windings included in the operation. Power relays with a complex configuration of a relay group are responsible for operational switching. As in the previous case, there may be additional filters, stabilizers and protection devices at the output, however, the main work is performed by a transformer and relay assembly under analog control.Electronic voltage stabilizers can be based on two conversion principles. The first is switching the transformer windings, but with the help of symmetrical thyristors, and not relays. The second principle is the conversion of current into direct current, its accumulation in buffer capacitors (capacitors), and then the reverse conversion into a “change” with a pure sine wave by means of a built-in generator. At first glance, the circuit seems to be quite complicated, but it provides an unprecedented high stabilization accuracy and high-quality line protection.Of course, there are other stabilizer schemes, including hybrid ones, but due to their highly specialized use or archaic nature, we will not consider them. Each of the three most common families has so-called childhood illnesses or congenital deficiencies in technology. And therefore, the most important task before sending the device to the service center is to establish whether the breakdown is the cause of non-compliance with the maintenance standards or an ordinary malfunction for this type of stabilizer.Typical faults of relay devices Relay stabilizers are characterized by an optimal ratio of cost and reliability. The relay group is exposed to the main wear, and with frequent or constant operation in the mode of increased load - also the dielectric insulation of the transformer windings.It is quite easy to diagnose a relay as the cause of a malfunction. The first step is to dismantle the components from the printed circuit board; they can be distinguished by a compact rectangular case, sometimes made of transparent plastic, with at least six pins.To determine the purpose of the terminals and the switching scheme, you can refer to the circuit diagram or technical specification for a specific type of relay according to the marking on the case.You can make a test switching on of the relay, for which the operating voltage is applied to the contacts of the coil, as a rule, it is indicated on the case of the product. The absence of a click when connecting is a clear sign of a burnt coil or stuck contacts. If a click is heard, but when the group of the main contacts is ringing, the circuit of their switching is not observed, the problem is most likely in the mechanism of rejection and pressing, or in charred contact pads.A significant part of electronic relays has a collapsible housing and can be serviced: restoration of the mechanism, cleaning the contact pads from carbon deposits with an eraser, sometimes even replacing a faulty coil. However, the best solution would still be to purchase new relays to replace the failed ones according to the article number or the location of the terminals.The loss of dielectric strength of the transformer due to overheating is accompanied by interturn short circuits and is externally observed as darkening or destruction of the winding insulation. The main feature is a significant decrease in resistance below the passport standards.Since most budget stabilizers have one solid primary winding and a multi-pin secondary, rewinding is not particularly difficult. In each link, the number of turns is small, they can be neatly laid even without a spindle or other winding devices. The most important thing is to accurately observe the number of turns and the direction of laying, as well as to correctly determine the initial resistivity of the conductors, and not just purchase a winding wire by diameter.Another type of transformer malfunction is the operation of a semiconductor thermal fuse, which is usually included in the rupture of one of the windings. To replace a semiconductor element, it is enough to clarify its series or basic parameters in order to select an analogue. Usually, the thermal fuse is connected in series with the first link of the secondary winding, so all outer turns will have to be removed to access it. The problem is diagnosed simply: between the beginning of the winding and the first tap, the circuit does not ring, but all the other turns are in perfect order.

Broken servo stabilizers The main reason for failure of servo drives is obvious: wear of the collector assembly. It is this shortcoming that is included in the category of childhood diseases that cannot be eliminated in most models of budget technology.There are two types of slip mechanisms. At low loads, conventional spring-loaded brushes do an excellent job of switching the windings. The device completely repeats the principle of operation of the collector motors of the power tool, except that the collector itself is deployed from a cylindrical position to a plane. The second type of current collectors has a brush assembly in the form of a roller, due to which friction during movement is reduced, which means that there is no intensive wear of the lamellas. At the same time, the wear rate of tile and roller brushes is approximately comparable.The disadvantage of a slip ring stems from its geometry. The contact spot is very small - only the line of contact of the cylindrical roller to the plane. True, in the most technically advanced models, the lamellae have radius grooves, although this solution is not entirely justified: as the graphite roller wears out, the contact area inevitably decreases. Depending on the intensity of use, replacement of brushes is required at intervals of 3 to 7 years. The situation can be aggravated in the presence of a large amount of dust and carbon deposits - up to the short circuit of several windings or a complete loss of contact.Although servo regulators are also susceptible to overload operation, their transformer will wear less. Unlike relay devices, in which voltage and current surges occur regularly during switching, the collector unit adjusts more smoothly, due to which the mechanical effect of the current is minimal. The varnish insulation of the windings still dries up and becomes brittle, but it does not crumble.Basically, the principle of operation of the servo stabilizer is extremely transparent. If, when turned on, there is an indication of the input voltage, but the device does not respond, the fault lies either in the drive itself or in the control and measuring circuit. In the latter case, a faulty circuit element can be easily detected purely visually or by dialing. If there is no voltage at the output, the transformer is faulty, but if the proper stabilization accuracy is not ensured, the presence of an interturn short circuit in the secondary winding, collector contamination, wear of the collector brushes or the lamellas themselves are evident.Common problems of electronic devices Inverter stabilizers are considered the least maintainable at home. There are several reasons for this, but the primary one is the need for special knowledge in circuitry and, in particular, the principles of operation of switching power supplies. It will not be possible to do without an appropriate material base: soldering equipment with temperature control, as well as measuring instruments. The set of diagnostic tools goes far beyond the limits of a conventional multimeter, you will need a device with an extended set of functions for measuring capacitance, frequency and inductance, and it is also desirable to have a simple oscilloscope at your disposal.The most common cause of failures in the operation of inverter stabilizers can be called a violation in the operation of the clock generator. It is necessary, based on the rated power of the device and the parameters of the transformer, to determine the optimal operating frequency of the pulse converter, and then compare it with the real parameters. Frequency failure is usually the result of a malfunction in the reference oscillating circuit connected to the corresponding pins of the clock IC.A complete failure of the device is possible for a number of reasons. If there is no built-in diagnostic system, or it is impossible to determine the breakdown by its indications, most likely the cause of the malfunction was the failure of the field or IGBT keys, which is quite simple to determine by the appearance of the case. Another typical cause of malfunctions is a breakdown of the built-in power supply of the control circuits; this part of the circuit is most vulnerable to voltage fluctuations, especially impulse ones.It will not be superfluous to make a continuity of all circuits, their conductivity must correspond to the circuit and electrical diagrams of the device. The most vulnerable elements include input and output rectifiers, transformer snubber circuits (for suppressing surges), as well as a power factor corrector, if any.General recommendations Electronic components are found not only in inverter stabilizers, they can be used in control and measuring circuits or indication and self-diagnosis devices. This mainly concerns passive elements and microcircuits with a low degree of integration: operational amplifiers, logic elements, combined transistors, current and voltage stabilizers.Failure of these elements can most often be determined purely by external signs: burnt out transistors and diodes have a cracked case, resistors - traces of burned varnish, capacitors simply inflate. Therefore, a close external examination of the printed circuit board is the first step in determining the malfunction.If it is not possible to visually determine the cause of the breakdown, a sequence of control measurements should be made.First, the conductivity and quality of the dielectric insulation of the circuit is checked in the off state. After that, when power is applied, voltages are measured at key points: at the connection terminals, after the fuse, on filters and stabilizers, transformer windings, and the main nodes of the control circuit.If the described diagnostic methods do not give a result, it is better to contact a service center, because even a simple breakdown can be very specific, despite the fact that amateur knowledge in electrical engineering and home conditions is not enough to eliminate it. published by my.housecope.com/wp-content/uploads/ext/941