How to check the armature of a VAZ generator. How to check the generator on a car without removing it. Checking the field windings

Body work

Car generator may fail for the following reasons:

  • wear of the excitation coil rotor bushings;
  • voltage regulator malfunction;
  • breakdown of rectifier bridge diodes;
  • short circuit or breakage of windings;
  • collector zone malfunction.

Most of these faults can be diagnosed without removing the generator from the car, since this work in some cars requires special tools, access from the bottom, and complex plumbing operations.

Diagnosing wear on excitation coil rotor bushings

Wear of the rotor (armature) bushings of the excitation coil leads to an increase in sliding friction, and as a result, overheating of the generator, a decrease in the efficiency of converting mechanical energy into electrical energy, and an increase in the load on the car engine.

Video - how to check battery charging from a generator:

In the most critical case, the bushing may break and the rotor may jam. This can cause the alternator belt to break, which in turn can lead to serious engine problems.

That is why timely prevention of the generator begins with the bushings. Sometimes bearings are used instead, although bushings are more reliable.

Bushing wear is usually diagnosed by a characteristic metallic ringing sound when the generator is running and an increase in the stretch of the generator belt.

It’s easier to remove the belt and check the runout of the generator pulley by hand, moving it perpendicular to the axis. The presence of even slight play indicates the need to replace bushings or bearings.

Voltage regulator malfunction

The voltage regulator ensures a constant voltage level at the generator terminals at different engine speeds. If you look at a typical generator circuit, the voltage regulator controls the field coil current.

The generator is a self-regulating system. If the speed increases, the voltage on the regulator increases, it reduces the current flowing through the field coil. According to the law of induction, the voltage on the stator coils decreases, and therefore the voltage at the generator output decreases.

Video - how to check the generator on a car without removing it:

During normal operation, the generator provides a stable voltage to the battery with the engine running, ranging from 13.3 to 14.5 Volts, regardless of engine speed.

An excess, like a lower voltage level, indicates possible malfunction regulator, it needs to be checked.

Structurally, the regulator can be made in the form of a block with brushes or without them.

Sometimes it is called a “pill” or “chocolate”.

In most cases, it can be easily dismantled without removing the generator and tested at home or in the garage. A typical voltage regulator test circuit is shown in the figure.

As lamp 6, you can use any interior light bulb. 1 – battery, 2 – relay regulator, 3 – electronic unit, 5 – terminal for connecting a thin wire going to the generator. If the lamp lights up, then the regulator is working. But if the battery charge voltage is more than 15 Volts, the voltage regulator still needs to be changed.

Video - checking the generator on a car with a multimeter:

It is also necessary to change the regulator if the brushes are very worn. However, if you have some experience in repairing power tools, you can try changing the worn brush (preferably both brushes at once).

In almost half of the cases, generator malfunction is caused by a failure of the voltage regulator.

Breakdown of rectifier bridge diodes

This is perhaps the most dangerous and difficult to fix malfunction. Very often it occurs when the battery polarity is reversed. This is when the battery terminals are connected in reverse polarity. In this case, several more fuses and units of the car may burn out.

Video - checking the generator at home:

Typically, diodes fail in pairs, since the breakdown of one leads to the supply of forward voltage to the series diode. When the diode breaks down, its resistance becomes almost zero.

In this case, the generator begins to overheat, increasing the load on the battery. A breakdown of the diode bridge can cause a short circuit in the electrical wiring and a fire..

If you notice a burning smell coming from the generator area or the generator is getting excessively hot, immediately disconnect all wires going to the generator, especially the thick wire. Carefully isolate them and proceed to the parking area.

Video - how to check the diode bridge on a car generator:

It’s easy to check the breakdown of the rectifier bridge diodes. The generator should “ring through” like a diode. To do this, switch the multimeter to the “Diode” position. Then disconnect all terminals from the generator. First, connect the multimeter probes between the thick wire terminal and the vehicle ground in one direction, then the opposite direction. It should “ring” in one direction (resistance from 200 to 1000 Ohms, like diodes in direct connection), but not in the opposite direction (resistance is very high, more than a hundred kiloOhms).

Of course, it is better to remove the generator, disassemble it, dismantle the diode bridge and test each diode individually.

Sometimes diode bridges of generators are called “horseshoe”, it is clear why. The round ones (6 pieces) are power diodes; they usually burn out and are difficult to change. When installing them, welding is not used. At worst, you can simply bite out a faulty pair of them without replacing them. The generator will still work, although not at full capacity. Cylindrical diodes serve the voltage regulator. They fail less often, but they also need to be checked as described above.

Short circuit or broken windings

If a winding break can still be somehow detected using a multimeter, and then by disassembling the generator, then a short circuit is poorly diagnosed, since the resistance of the windings is low.

Video - how to check whether the generator is working on a car without removing it:

The main sign of a malfunction in the generator windings is a change in the color of the varnish insulation of the copper conductors of the generator winding. With increased short circuit currents, the color of the wires becomes much darker. This is accompanied by a burning smell when operating the generator.

You can send the generator for rewinding, but this is now expensive. If it is possible to buy a similar one or with matching landing dimensions from another car, it’s better not to rewind.

Changes in the color of the windings can be detected visually. The generator has many technological holes for cooling; in good lighting, you can examine the color of the windings.

Collector zone fault

The commutator is the brass cylindrical contacts of the exciting winding along which the brushes move

They usually wear unevenly. This leads to sparking in the brush area, overheating of the commutator, and even greater wear of the brushes and commutator.

During generator maintenance, the collectors are bored and ground. This cannot be done endlessly, so after several repairs the collectors are replaced.

Video - quick check of the generator without installing it on the car:

You can diagnose collector wear when the generator is disassembled. If you remove the voltage regulator with brushes, you can feel the commutator area with your finger. If she is “humpbacked”, you should think about prevention.

You can detect sparking brushes when the engine is running, and this is evidence of commutator wear, at night by turning off all lighting fixtures.

The generator is one of the most conservative components of a car. Its design has remained virtually unchanged for more than fifty years. If carried out on time routine maintenance(cleaning, replacing bearings or bushings, belts, brushes), it will last a long time.

Video - how to ring a generator with a multimeter:

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Comments on the article:

    Alexander

    I usually check the generator in the fall, before the cold weather. This takes a little time, but saves you from additional expenses for buying a new one or repairing it. Lubricate and wipe the collector on time. As practice shows, it is true that most often either the regulator or the diode bridge fails, but in this case not everyone can cope with such a problem on their own.

    Valentine

    The rectifier bridge, consisting of diodes and a regulator, gets quite hot during operation, and its cooling is very weak due to its design features (located at the rear of the generator).
    When driving into a deep puddle, the immediate flow of water from under the wheel causes a sharp cooling of the diodes, in my practice this is the reason for their failure in 80% of cases.

    Oleg

    Failure of the bridge diodes can be detected by the battery being undercharged. On my Chevrolet Niva, due to the failure of the reverse diode, the lamp on the panel was constantly dimly lit. When I disassembled the generator, I simply rang all the diodes with a multimeter - one was broken. I bought a diode in the radio tent (there are no Russian ones, only an imported analogue) I soldered and assembled the generator. All work for 12 rubles. and an hour of work. At the service center, they first offered to change the generator - work + generator cost about 5,000 rubles.

    Sergey

    I have a special relationship with the generator: two of my cars had the same problem. First, the battery of one car began to be undercharged (there was no charge indicator lamp on the panel), and the charging lamp of another began to glow dimly. For both cars I followed the same path: first I measured the battery charge voltage at the terminals. Then I changed the “tablets”, and only lastly did I disassemble the battery. In both cases, the diode in the horseshoe is broken. In the first case, I couldn’t find the diode (this was during times of shortage), so I replaced the horseshoe. I remember it cost about 200 rubles. In the second case, I found an imported analogue in the directory. I bought it (15 rubles), resoldered the diode and all the problems went away. But in neither case, as the author of the article writes, was the second diode affected. By the way, the service offered replacement of generators and nothing more.

    Lyokha

    I agree that you don’t have to be an ace in radio engineering to carry out simple measurements with a tester. I try not to get involved in auto electrics once again, there are specialists for this, but sometimes need forces it. On personal experience I came to the conclusion that serious breakdowns are rare. Usually, either the brushes are worn out or the wiring is broken (burnt out, poor contact). I sincerely advise you - do not rush to buy a new generator; in 49 out of 50 cases, repairs cost pennies (or are completely free).

    Vasya

    I doubt it's worth checking it with a tester at all. The average car enthusiast is only interested in whether the generator is working or not. To do this, simply disconnect one of the terminals from the battery with the engine running. If the engine does not stall, then the generator is working. This method is actually harmful to both the electronics and the generator. But nevertheless the most effective :)

    Kolya

    Here I read that it is recommended to check by disconnecting the terminal on the battery. So you can’t do this! If such a focus channel is on domestic cars (Zhiguli, Volga, Moskvich) where, in principle, everything is oak and analog, then on a serious foreign car you can easily end up buying a generator or, even worse, a control unit. But I think it still makes sense to measure the voltage on a running motor with a tester. If it begins to deviate from the standard 14.4 Volts, then this may indirectly indicate wear of the generator brush assembly. In this case, it’s better to be on the safe side than to be left without a charger in the middle of the road.

    Sergey

    The generator may be in good working order, but the indicator light may be flashing, which may indicate a problem with the wiring outside the generator. Therefore, self-checking is not so simple. It is better to carry out a full diagnosis by electricians at a service station, where they can determine in advance an unexpected breakdown and the percentage of wear. But there are advantages to self-testing - you gain certain knowledge and skills.

    Dmitriy

    A generator is practically an ordinary electric motor; if you spin it and connect a light bulb, it will start to glow - this is an elementary generator.
    Its main malfunctions are: jammed bearings, one of the common problems with generators that have been in use for a long time; the winding of either the stator or rotor burned out, most often from high speed travel through water; failure of the brush assembly; failure of the relay regulator.
    If the generator stops working, this can already be seen in the cabin - the battery emblem on the instrument panel will light up. You must react immediately, otherwise you may drain the battery. The second signal is a dim glow of all instruments, which means the car is running on battery power and not on a generator.
    There are two ways to do this check. The first is a multimeter. We measure the voltage at the terminals with the engine not running - it should be 12.5 - 12.7 V. We start the engine - it should be 13.8 - 14.5, although some manufacturers say 14.8. Then we turn on the load - the voltage should not fall below 13.7 V. If it is lower, 12.8 - 13V, then the generator is not working, you need to check it.
    The second method is the old grandfather's method. Do it very carefully!!! We turn on the engine, turn on the load and remove the negative from the battery. If the car continues to work, the generator is working, if it stalls, the generator is dead. So I checked it on a VAZ 2108, Mazda, Opel, Chevy Niva.

    Irina

    She worked at a service station. They didn’t make the generators themselves, they took them to a specialist for generator repair. And you’re talking about yourself here!

    Danila

    Well, first I want to answer the last commentators Dmitry and Irina. The test method by disconnecting the battery is fraught with failure of the car's brains; old cars had no electronics, except for the switch on the VAZ 2108 and there was nothing to burn there. The battery is a rather large load on the generator and when it is disconnected, a sharp increase in voltage is possible, which is fraught. Now Irina - your “specialists” didn’t do it themselves only because they didn’t want to waste time, but any driver versed in technology can fix the generator (except for rewinding it). Now to the check. I only check with a multimeter, if the voltage on the battery with the engine off is 12.4-12.6, then with the generator running it should be 13.5 - 14.5.

    Igor

    The generator is the most important part of the car; your ability to drive the car and battery drain depend on its failure. To prevent this from happening, you need to monitor the condition of the generator.
    However, there are mandatory rules that, if followed, will prevent damage to the generator. This includes: checking the generator for a spark, i.e. for a short circuit, this also includes the connection of terminal “30” to ground; operation of the generator with the battery disconnected; any welding work by car with the generator on; checking generator diodes (horseshoes) with voltage more than 12 V.
    To check the generator, I personally use a multimeter with a Krona battery, it is 9 volt. Most often the voltage regulator fails and to check it, I first warm up the engine for 10-15 minutes. Then, in the position of a voltmeter with a scale of up to 20 V, I measure the voltage between the generator ground and the “30” mark. The voltage should be in the range of 13.5-14.5 V. If it is lower or more, the regulator may have failed, I have a spare one and I use it to check.
    In addition, you can check the voltage on the battery, it should be above 12.6 V.
    For those who understand car electrics, there is also a check of the diode bridge, the return current and the excitation current of the generator.

    Anton

    On my Seven Zhiguli car, I have repeatedly had to repair or replace the generator. This is one of the bottlenecks on my car. There are two main problems of breakdown. The first is failure of the generator drive tension belt pulley bearing; the second is a breakdown of the generator rectifier bridge. For the first failure, the diagnosis is simple, the noise of the bearing can be heard far from the car, but the second reason can only be determined by removing the generator. If you have a device, you can also do diagnostics without removing it, but you will still have to remove it, since the bridge will need to be replaced.

The malfunction of the car generator is classified as critical, in which further operation vehicles not allowed. You can use a multimeter to check the functionality of the generator.

Signs of abnormal operation of a car generator may include:

  • no “battery” indication on dashboard when the ignition is turned on;
  • the “battery” light glows after starting the engine;
  • periodic blinking of the “battery” signal indicator while driving;
  • the smell of burnt electrical wiring in the generator area;
  • failure to start the engine after parking.

Lack of battery charge with a faulty generator leads to problems with starting the engine. More dangerous is a malfunction associated with exceeding the charging current and voltage. car battery. Many car enthusiasts use a donor battery to start the engine, after which they disconnect the battery terminals to switch to charging their own battery. At this moment, the vehicle's electrical equipment is powered by a generator.

If the generator is faulty, the voltage in on-board network may be more than 17 volts, which leads to breakdown of the protective zener diodes in the engine control unit. In this case, expensive repairs to the engine control unit are required.

Causes and possible consequences of the malfunction

The generator may not work for the following reasons:

  • malfunction of the voltage regulator (“pills”, “chocolates” in the slang of car enthusiasts);
  • wear (destruction) of brushes;
  • short circuit of the exciting winding (rotor);
  • breakdown of diodes (located in the horseshoe);
  • wear of bearings and bushings.

A faulty voltage regulator usually results in a lack of battery charge. In this case, the “battery” indicator light appears on the dashboard. The engine continues to run until the battery is discharged to approximately 8 - 9 volts.

During daylight hours, the battery charge may be enough for 30-50 kilometers, provided that the battery was well charged at the time the malfunction occurred.

If the output stages of the voltage regulator breakdown, a malfunction may occur due to an increase in the generator output voltage to 17 - 20 Volts. In this case, recharging occurs battery. The consequence of overcharging is the process of boiling of the electrolyte. If signs of corrosion appear under the hood in the battery area, it is necessary to check the generator.

A breakdown of the diode bridge can occur when the battery is accidentally reversed (installing the terminals in the wrong polarity). Typically, diodes are punched in pairs in one arm. A faulty diode has a resistance close to zero. In this case, the stator winding of the generator operates in short circuit mode and becomes very hot.

After a few minutes of engine operation, the windings overheat, and a smell of burnt electrical wiring appears under the hood of the car. To avoid fire, the engine must be turned off and the generator checked.

Wear of the brushes leads to gradual failure of the generator. First, while driving, the charge indicator light on the dashboard begins to blink, then it begins to glow constantly. In many generator models, the brushes are changed together with the voltage regulator.

A short circuit in the generator windings can lead to a significant change in output parameters and overheating of the device.

Initial check sequence

An initial performance check can be performed without dismantling the generator. To do this, set the multimeter switch to the “constant voltage 20V” mode. Next, connect the black probe to the negative terminal of the battery, the red one to the positive terminal. After this, you need to start the engine and let it reach a stable idle speed. Multimeter readings ranging from 13.5 to 14.5 Volts are considered normal.

If the multimeter shows a value less than 12.8 Volts, the charging process either does not occur at all, or the charging current is extremely small. The generator is operating in abnormal mode. When the voltage is more than 14.8 Volts, the battery is overcharged. This can lead to boiling of the electrolyte, an increase in acid concentration, and destruction of the battery plates.

To check the voltage at the generator output, you need to turn on the car lamp in the open circuit from terminal 30 on the generator (the point of contact with the thick wire leading to the positive terminal of the battery or starter).


Next, connect the multimeter in the “=20V” mode with the red probe to contact 30 of the generator, and the black probe to the stripped contact on the engine or body. Start the engine. The reading on the multimeter should not be more than 15.5 volts whenever the accelerator pedal is pressed. Otherwise, further operation of the generator is dangerous for the electrical equipment of the car.

When checking, you should evaluate the degree of tension of the generator belt. Using a simplified method, this can be done by pressing on the belt with your finger.

The amount of deflection should be within 0.5 - 1 centimeter. At the same time, check the degree of belt wear.
To determine the reasons for abnormal operation of the generator and perform repair work, dismantling the generator is required.

Checking generator components

The test begins with monitoring the functionality of the voltage regulator. To do this, the regulator is removed from the generator and a simple electrical circuit is created.

Any car interior light bulb can be used as an incandescent lamp. If voltage regulator 3 is working properly, lamp 6 should not glow at full power. When connected in parallel with the lamp (brushes) of a multimeter, its readings should be from 5.0 to 10.0 Volts. If the multimeter readings fall outside these limits, the regulator must be changed. The design of some generator models allows for the possibility of replacing the regulator without dismantling the device.

Next, check the exciting winding of the generator for breakdown. To do this, set the multimeter to resistance measurement mode at a limit of 200 kiloOhms. The probes are connected: black - to the commutator lamella, red - to the metal part of the armature. The resistance should be more than 100 kiloohms or higher than the upper limit of measurement, as shown in the photo.

The resistance between the lamellas (rotor windings) is usually 0.5 - 2 Ohms.

Checking the stator begins with checking the windings for breakdown. To do this, the red probe of the multimeter is connected to the metal part of the stator, the black probe is connected in series to the windings.

The resistance must be above the upper measurement limit. Then the resistance between the winding contacts is measured. They should differ by no more than 5%. The measurement limit of the multimeter is set to 200 ohms.

If the winding has an electrical breakdown, a short circuit of the turns or a break, it must be replaced. There are workshops that rewind stators and rotors.

To check the health of the diode bridge, the multimeter measurement mode is switched to the “diode” test. Then the diodes (their number on a horseshoe is usually 9) are sequentially “ringed” in forward and reverse connection. In the forward direction (black probe to the cathode) the resistance is 550 - 700 Ohms, when switched in reverse it is greater than the maximum measurement limit.

When the diodes breakdown, the resistance in all directions will be practically zero. This diode should be changed. The difficulty of replacing a diode lies in the fact that the diodes in generators are not soldered, but spot welded to ensure reliable contact at different temperature conditions.

A car generator is an important part of a car's electrical equipment. At the first sign of inoperability, it is necessary to check it using a multimeter.

Failure to charge the battery can have unpleasant consequences: there is not enough energy to power consumers, and the engine stops starting. To understand the cause of the malfunction, it is necessary to check the generator; in car services, diagnostics are often carried out on a special stand, for this the unit is removed.

But there are also methods for checking the charging source on site, where there is no need to dismantle the generator; in some cases, the problem can be fixed quite easily. In this article we will look at what quick diagnostic methods there are and what you may need for this.

How to check the generator on site

There are main reasons for poor starting of an internal combustion engine; the starter turns poorly if:

  • the battery is old or faulty, does not charge and does not hold a load;
  • battery cables do not provide reliable contact, for example, due to oxidized terminals;
  • there is no reliable mass of the engine with the body;
  • the generator does not provide the required charge;
  • loosely stretched drive belt, because of this, the generator rotor does not rotate at full strength, since the belt slips under load.

There are different types of generator failures, the most typical of which are:

  • breakage of wires approaching the node;
  • breakdown of the diode bridge;
  • malfunction of the relay regulator;
  • short circuit (burnout, break) of the rotor or stator winding;
  • bearing wear;
  • brushes wear out or break.

The worst thing that can happen is that the bearings jam or the windings burn out, but in this case it’s easy to check the generator’s functionality; its condition can be easily determined by external signs:

  • The generator pulley and shaft do not rotate when the engine is running;
  • a specific smell of burnt windings appeared.

The main ways to check a generator on site are an external inspection of the parts of the generator assembly and measuring the voltage (U) with a multimeter (voltmeter). With the engine running under load, the voltage should drop slightly, but only to a certain value; if it is below normal, it is necessary to specifically deal with the generator device.

The functionality of the generator without removing it from the car is checked according to the same principle, regardless of the car model, be it a foreign car or a VAZ-2106. In this case, it is not necessary to connect a multimeter to the generator connectors; you can measure the voltage directly on the battery. We check the generator with a tester as follows:


If the charge almost does not drop under load, this is very good; it means that the generator is practically new, and the battery is in excellent condition. When the voltmeter shows a voltage of less than 12 V with the engine stopped, you first need to start servicing the battery, first of all you should recharge it. You also need to take into account that constant undercharging of the battery leads to the destruction of the battery plates; in advanced cases, it is necessary to repair the generator and restore the battery’s functionality (sometimes it needs to be replaced).

Removing the battery terminal while the engine is running is an old, proven method of checking the functionality of the generator; this method was used back in Soviet cars. We check like this:

  • start the engine;
  • disconnect the negative terminal and move it to the side;
  • if the engine turns off, it means there is no charging, you need to deal with the generator;
  • Without installing the terminals, we add speed, the internal combustion engine should not stall.

Another point you should pay attention to is when installing the negative wire in place while the engine is running idle speed should not change noticeably. A significant decrease in speed indicates that the battery is quite discharged, and attention should be paid to this. A discharged or faulty battery may fail on the road; it is better not to travel with such a battery.

An important point is that you need to remove the terminal with the engine running very carefully; the wire should not touch live parts of the car (body, engine housing, etc.). On many modern cars disconnect the terminal during internal combustion engine operation It is generally not recommended; if there is insufficient confidence in the test results, it is better not to use this method.

It is worth noting that there is still a way to check with a test light, but we will not consider this method - the lamp only indicates the presence or absence of charging, with its help it is impossible to determine the value of the voltage in the network and its dependence on the load.

Signs of a weak alternator charge

In order to understand that the generator does not provide normal charging, it is not necessary to take measurements; the malfunction can be determined by various signs:

  • while the engine is running, the charging indicator lamp on the instrument panel blinks or lights up;
  • under load (headlights, heater on rear window etc.) engine speed drops;
  • The headlights burn dimly, this is especially noticeable when turned on high beam;
  • When the engine speed increases, a whistle is heard, the cause of which is a loose drive belt, so charging also drops.

The on-board power supply indicator lamp must light up when the ignition is turned on and go out when the engine is running. If the instrument panel light does not light up at all, it may be burnt out and need to be replaced. Light indicators are now installed on almost all modern cars; previously, voltmeters were mainly used to monitor the state of the electrical network. These meters have ceased to be used due to the large error in the readings: it is difficult to determine from the voltmeter on the instrument panel exactly what kind of charging the generator is providing, but the warning lamp is difficult not to notice if it lights up.

Causes of battery undercharging

A car battery is an energy storage device: while the engine is running, it is charged from the generator, and then gives its energy to the starter to start the internal combustion engine. If the battery is not fully charged, it cannot provide normal cranking to the starter, causing problems:

  • the engine does not start or starts with great difficulty;
  • when the headlights or other consumers are turned on, the light on the instrument panel dims;
  • the car has to be started by various unpopular methods - from a pusher, from a tow, by lighting it with another battery.

When there is undercharging, the indicator lamp on the instrument panel lights up at half intensity, the main reasons for this phenomenon are as follows:

  • there is damage in the diode bridge - one of the diodes is broken;
  • the relay-regulator (RR) is faulty;
  • The generator brushes are worn out, or they do not fit tightly to the ring at the end of the armature (there is no reliable contact).

The voltage regulator (relay), more often than other parts, is the cause of this malfunction; it is one of the most vulnerable parts in the electrical part of the machine. To check or replace the relay-regulator, you often have to remove the entire generator assembly, but there are many car models where the removal and replacement of the RR can be done on site, without dismantling the generator assembly.

Recharging the battery

The generator does not always undercharge the battery; it happens quite often when overcharging occurs, that is, the generator unit produces voltage above the prescribed norm. As a rule, the cause of overcharging is a faulty voltage regulator; it does not work as expected, and the generator continues to produce current when the battery is fully charged.

Without removing the generator from the car, the relay-regulator is checked in the same way as with undercharging, only in this case the multimeter shows the voltage of the on-board network when the load is on more than 14.7 V (readings can be even higher, for example, even more than 17 Volts) . Constant overcharging is dangerous because it:

  • the electrolyte in the battery banks begins to boil;
  • lead plates of the battery are exposed;
  • sulfation occurs (destruction of the plates), the battery becomes inoperable;
  • Due to increased voltage, light bulbs may burn out, electrical equipment may fail, and fuses may burn.

There is still a danger of a battery explosion, which occurs due to clogging of the holes in the plugs of the battery cans when the electrolyte is boiling.

On many VAZ cars of the “Classic” family (in particular, on the VAZ-2106), the voltage relay can be changed quite easily, as it is located separately, located next to the front fender of the car. The relay-regulator of the VAZ-2105 and 2107 type is located in the generator itself, it is a little more difficult to get to, but replacing it is also easy.

The main source of current in a car is the generator. Without a working generator, the car will not go far. If the generator malfunctions, the battery does not charge sufficiently, which leads to a gradual loss of power to electrical appliances and subsequently leads to the inability to continue driving.

Therefore, it is so important for car enthusiasts to maintain the performance of one of the key components of the car.

Generator malfunctions can manifest themselves in the most different ways, but most often you should pay attention to the generator if there is any noise coming from the generator, or if you often notice insufficient battery charge or a complete absence of it.

This can be noticed very simply. The car did not start, you started it by lighting a cigarette from another car. We went somewhere, turned off the engine, and then again you couldn’t start the car, the starter wouldn’t turn. That is, either the battery has served its purpose, or the generator is not charging it.

Diagnosis of mechanical generator failures

Here, in general, everything is simple. If it makes noise, squeals, whistles, rattles, howls, then the problem is either in the bearings, which must be checked for lubrication and wear. Sometimes it is enough to add lubricant and the noise disappears. In more serious cases, the bearings must be replaced with new ones.

In addition to bearings, noise and howling can appear in the event of interturn short circuits in the windings of either the stator or the traction relay. Also, the cause of unpleasant sound can be a short circuit of the windings to the housing or bad contacts. That is, it is obvious that sound appears in the event of mechanical interaction of any parts of the generator during its operation. All this can be revealed by visually inspecting the generator. Where contact occurs, traces of this contact will most likely be visible.

Having discovered a breakdown, you should assess the degree of its severity and the possibility of repair. But mechanical problems, this is not the only thing that can disrupt the operation of the generator.

Checking the voltage of the car generator

In order to establish the functionality of the generator, you should check its output voltage, and then diagnose the main causes of malfunctions. To measure voltage, a voltmeter is most often used, which is connected to the poles of the battery, or less often - an ohmmeter or multimeter.

When starting the engine, the voltage at the engine terminals should not exceed 8 V. It is better to carry out the procedure not on a cold engine and an ambient temperature of at least 20 degrees Celsius.

To continue the experiment further, you need to “step on the gas,” thereby increasing the engine speed. This must be done until the tachometer needle shows 3000 rpm. Then you should take another voltage measurement at the battery terminals. If the reading is less than 12.5 V, it’s time to start repairing the generator.

Dismantling a faulty generator requires disconnecting the ground terminal from the battery. Then, using a screwdriver, you need to disconnect the voltage regulator mount.

Before moving on to more detailed diagnostics, it is necessary to carry out an external inspection of the generator, namely, check the wear of the brushes and slip rings and, if there is carbon deposits, grind them.

Most common cause If the generator malfunctions, the voltage regulator is faulty, so it is better to change it periodically before the expiration date of the part.

Installation of the generator in its original position is carried out in the reverse order, at the end the mass is carefully connected to the battery.

After completing these simple steps, you need to reconnect the voltmeter to the battery poles. When starting the engine and raising the speed to 3000 rpm, the measuring device should show a voltage value in the range of 13.5-14.5 V. This voltmeter value will mean that the cause of the problem has been eliminated.

Checking voltage stabilization

The next step should be to check voltage stabilization. It is carried out as follows. With the car's high beam headlights on, use a voltmeter to take the necessary voltage measurements. If the resulting indicator does not differ by more than 0.4 V from the previously measured value, then everything is in order.

The method described above for checking a car generator is simple and uncomplicated and requires only the presence of a measuring device, the basic skills of a car mechanic and the desire to independently understand the reasons for the malfunction of the iron horse.

Checking the vehicle's power supply circuit

Using a measuring device, we can check the vehicle's power supply circuit.

To check the diode bridge, you need to connect a voltmeter to the generator terminal and ground. The likelihood of diode failure will be obvious when the voltage reading is above 0.5 V.

To determine the breakdown of diodes, you need to connect the device between terminal “30” and the disconnected generator wire. A discharge current reading of less than 5 mA will be acceptable.

To check the voltage regulator, you will first need to warm up the engine at medium speed with the lights on for at least 15 minutes. Next, using a voltmeter, you need to measure the voltage on one side at ground and on the other at terminal “30”. Voltmeter readings for different cars may vary.

If necessary, you can check the regulated voltage. To do this, you need to connect the measuring device to the battery. With such a check, it is necessary that the speed is close to maximum, and all energy consumers are turned on. The value obtained during measurement will be individual depending on the modification of the car.

To diagnose the resistance in the excitation winding, an ohmmeter and a multimeter are used. First of all, the voltage regulator and brush holder are removed. Next you need to make sure the integrity of the winding and clean the slip rings. When checking resistance, the probes of the measuring device must be applied to the slip rings. A normal reading will be considered to be 5-10 ohms.

To check for a short to ground, you must use a multimeter. One probe of the device must be attached to the generator stator, the other must be connected to the slip ring. If the winding does not short to ground, the multimeter will show an infinitely high resistance.

Elimination of minor faults is possible and on our own, however, it should be remembered that for more thorough diagnostics, complex measurements and subsequent repair of the generator, you need to contact certified services.

A properly charged battery is an indispensable condition for a comfortable ride. During the cold season, it is especially important that the battery ensures reliable starting of the car engine.

Modern cars, especially luxury cars, have a battery charging control unit that monitors the main parameters of the process. There are no such devices in budget category vehicles. Experienced drivers perform this task independently. Let's look at how to have the most complete control over the battery charging process.

Causes of battery charging failure

The main parameter in the battery charging process is the charge current. Many parameters depend on its value.

Capacity replenishment speed

There is an opinion that for normal battery charging, the charge current should be 10% of its capacity, i.e. with a battery capacity of 50 Amp*hours, the charging current will be 5 Amps. Under such conditions, it will reach its nominal capacity of 10 hours.

Imagine, you were turned on by the wires of another car in the winter, and in order to fully charge the car battery, you need to drive the car for 10 hours straight, that is, drive about five hundred kilometers.

It is believed that to replenish the battery charge to the nominal value, it is enough to drive 30 kilometers in a normal cycle, and in city traffic jams half that. That is, if your work is located more than 10 kilometers from home, this is enough not to worry about recharging the battery outside the car.

The case is different when work is close to home. You spent the capacity when starting the car, quickly drove to work, and then also home. After a week or two, your battery runs out. And not at all because there is something wrong with the car, it’s just the rhythm of the drive.

In this case, you should think about warming up the engine even in the warm season just to ensure that the battery is always charged.

Let's return to the charge current. If it is enough to drive a car 30 kilometers to fully charge the battery, and not 500, as in the example, therefore, the charging current of the car generator is not 5 Amperes, but much higher.

Battery life

The normal battery life is more than five years. Used cars imported from abroad have fully working seven- to nine-year-old batteries on board. There, however, the storage conditions for cars are different, and the temperature in winter is higher.

There are three reasons for the low durability of the battery: violation of the battery charging mode, the quality of the battery, the human factor, in other words, laziness.

Let's start with the first one. If the battery is not charged to full capacity all the time, the plates undergo a sulfation process. Sulfation, or the formation of lead sulfate on the plates, can be compared to a stomach ulcer in humans, only in humans it can be treated, but a battery ulcer is practically untreatable.

There are various methods of complete discharge-charge, charging with pulsed currents. Maybe there is some percentage recovery, but if the battery is completely dead, then alas...

The quality of the battery depends on the manufacturer. Modern technologies only affect the increase in battery capacity while reducing the size and weight, respectively, the amount of lead.

Better quality? If there are two different copies with the same capacity, starting current, cost, it is better to buy the one that is heavier, it has more lead, it will last longer.

About the human factor. The biggest mistake car owners make is parking the car in the fall with the battery until spring.

If the battery spends several months in a discharged, not even fully charged state, and even in the cold with a reduced electrolyte density, it is unlikely to survive until spring.

If you periodically use your car in winter, then regularly (a couple of times a week) you need to start the car and warm it up for at least fifteen minutes, checking the charging voltage.

If the car is not used in winter, it is better to remove the battery from the car, fully charge it and store it in a warm room, recharging it once a month.

During daily use vehicle It is necessary to regularly check the charging of the battery from the generator.

How to check battery charging from a generator

Checking the battery charging process is possible using the following methods:

Visual control

Visual diagnostics can and should be done at least once a week.

In summer, it is imperative to monitor the electrolyte level either through the light or through the electrolyte filling holes. If the battery is maintenance-free, monitor the indicator window.

When the recharging process is underway (the charging current is too high, it is possible when the generator is faulty), the electrolyte boils away. This leads to an increase in acid concentration, corrosion of the plates, and an even greater increase in current and temperature.

Video - charging voltage of a car battery from a generator, leakage currents and other checks:

Such an avalanche-like process can destroy a battery in a couple of hours. Therefore, if you see any changes in the paint above the battery installation site, foreign deposits, or a change in the shade of the battery case near one of the cans or electrolyte refill caps, immediately determine the cause.

If the control window of the battery is not in the green zone during constant operation, it means that the charging process is disrupted.

The visual method also includes monitoring the “battery” light on the dashboard. If it does not light up when the ignition is turned on, or does not go out after starting the engine, or flickers depending on the engine speed, then the battery charging process is disrupted.

Another tip for visually checking the charging process. At night, pay attention to the brightness level low beam when engine speed changes. This is best done by lighting a white wall. If the brightness increases with increasing engine speed, it means that the voltage-current regulator in the generator is not working properly, you need to check the generator.

Computer diagnostics

Computer diagnostics of cars equipped with a battery charge controller will give full picture operation of the generator, charge control unit, battery performance level.

But there are few such cars. Conventional computer diagnostics will provide information about the voltage of the on-board network. But it can also be obtained using a regular multimeter.

Diagnostics using devices

Experienced drivers remember that a garage tool always included a hydrometer and a load fork.

The battery hydrometer is used to measure the density of the electrolyte. Normal density is from 1.23 to 1.28 g/cm3. The lower the temperature, the higher the density must be, otherwise the battery will freeze and fail.

Using a load fork, you can identify a “rotten” can and repair it.

Now the cost of repairs will be more than the cost of a new battery, so these devices are not used in amateur practice.

The most universal device for monitoring battery charging is a multimeter. How can I use it to check the battery charge?

First, before driving with a cold engine, measure the voltage at the battery. It must be at least 12.5 Volts. Turn on the ignition. Normally, the voltage will drop by 0.1 - 0.3 Volts, but still must be at least 12.4 Volts to start the engine.

If the voltage is higher, the battery is being recharged. This is possible in the following cases:

  • the generator is faulty (voltage regulator, diode bridge, short circuit of the excitation winding);
  • Lost battery capacity (aging, boiling, destruction of plates);
  • violation in the battery charging control unit (if equipped).

If the voltage is less than 13.5 Volts, this indicates that the charge is weak, the generator voltage regulator is not working properly, and there may be problems with the wiring.

In the case when the voltage has not changed at all, on the contrary, it has decreased, it is necessary to check the generator or electrical wiring.

Using a multimeter you can measure the charge current. To do this, you need to disconnect the thick wire from the generator. Carefully insulate it (there are + batteries on it). Next, connect one multimeter probe to the free contact of the generator, the other to the positive of the battery.

Switch the multimeter to the “current measurement” mode to the 10 Ampere limit. Start the engine. The charging current will initially be large (more than 5 Amperes), then as the battery charges, it will decrease.

Checking the battery charge must be done at least once a month, and winter period and more often. After all, at this time of year from proper operation The safety of the driver and passengers depends on the battery.

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