That not so long ago I wrote an article about, in fact, this happens for two reasons, when the battery is already dying and needs to be checked, and when the battery is new, it also needs to be tested before buying. But is it always about the battery? Why suddenly he can fail, one thing - if it is winter and it is really difficult for him to work, another thing if summer and he is not "mur-mur" at all. YES also on the instrument panel, the battery sensor starts to blink from time to time, or it is constantly on! In such situations, you should not run "headlong" for a new battery, first you need to establish the reason why it failed, because in 50% of cases it can be just a generator. Moreover, the check is quite easy to do without removing from the car, let's get more details ...

Indeed, guys, I have a lot of friends who first ran after a new battery, but later it was also discharged to zero. The fact is that before buying, you MUST check the generator! After all, think for yourself, if it does not recharge the battery (or there is no charge at all), then it will be discharged to zero after a day or two of operation, I will say more it is easy to bring it to that even for a new battery, it is very bad, you will immediately lose about 10% of the capacity , DO YOU NEED IT? Therefore, I will repeat again - ALWAYS CHECK THE GENERATOR

Why is the generator failing?

The generator itself has a simple structure, if you want, then this is an ordinary electric motor (only made taking into account a large current generation), try to twist a regular electric motor and connect a light bulb or an LED to it, then it will start to burn - here is an elementary current generator for you.

Someday I will have an article in which I will tell you what the generator consists of. BUT today it is simple and exaggerated - this is a rotor (moving part), a stator (stationary part), a brush assembly, and of course the body in which the whole thing is located.

And now the actual breakdown.

• Bearings seized. This is a fairly common problem with already worn out generators, the rotor in the housing rotates on bearings, from time and moisture (dirt), they wear out and wedge or wedge from corny. If there is a wedge, then this is one thing - the stem stops rotating. But if wedging occurs, then it is difficult to notice, the rod may or may not rotate. In any case, with such symptoms, the belt that turns the generator from the engine is more likely to break. THIS IS THE FIRST CALL.
• The winding on the stator or rotor is burnt out. It is there in any case and will most likely be on the stator, and so - also from moisture (salt on the roads), it can corrode and it will corny or simply burn out, since copper wires are used there. Accordingly, the current generation will stop.

• Failure of the brush assembly. This is also very common, brushes are graphite (often square) rods that run along the stator tracks. So from time to time they wear out corny and they need to be replaced.
• Failure of the regulator relay. This relay prevents the generator from recharging the battery, bringing the voltage and current into the required range. Often, it also fails and charging does not go to the battery at all! You need to watch.

In general, for these 4 main reasons, the generator may not work, so it must be checked before buying a new battery. It is likely that you are dealing with it.

Vehicle tips

Actually, I already told you about them from above, if the generator refuses to work, then it is easy to notice even inside the cabin.

• All modern cars will be signaled by a warning lamp - "red battery" on the instrument panel. If it is on or even blinking, then there is nothing good in this, you need to immediately react, otherwise the discharge is not far off.

• Weak glow of all devices. The "control lamp" may burn out, but if you notice that the devices have begun to shine dimly, then this means that the car is running on a battery, and not on a generator. Again, you need to check.
• Broken belt. If you climbed under the hood, and there you saw a break in the belt that turns the generator, then CHECK OPERATING CAPACITY MANDATORY! Otherwise, again, you can kill your battery.

These are all obvious malfunctions, but it happens that the battery is dead and everything seems to be fine, but something inside "gnaws" - isn't it a generator? How to check quickly and easily by car without taking off? Question? And here everything is easy enough

Check without removing from the car

There are two 100% ways that I personally advise you.

1) Checking with a multimeter... Of course, not everyone has it, but in fairness it is worth noting that this is a fairly common device and, say, your father - neighbor - friend, will have it "anyway". To begin with, we measure on the idle engine, at the battery terminals, it should be about 12.5 - 12.7 V., ideally.

We start the car, do not gas, and do not turn on any electrical devices - with the engine running, we measure the voltage, it should be in the range of 13.8 - 14.5 Volts.

However, on modern cars, where a lot of electronics are crammed, manufacturers assure that 14.8 Volts IS ALSO A NORMAL INDICATOR. About this below. Next, we connect the load - headlights, a stove, heated rear window, foglights, a radio tape recorder, after that the voltage should sag slightly - but not lower than 13.7 - 14.0V. If it is lower, say 12.8 - 13V, then the generator does not work, you need to check it.

Let's summarize a small summary:

Normal battery voltage - 12.5 - 12.7V

After starting the car - 13.8 - 14.5V, on some modern cars - 14.8V

After turning on the maximum load, it should be - 13.7 - 13.8 V

If the voltage is below - 13V, urgently CHECK THE GENERATOR

2) The old grandfather's method... This can be checked on almost all machines, and this method is 100% working. But you need to do everything very carefully. So - we start the engine, turn on a not very heavy load (for example, headlights or heated rear window). And on the working engine, we need to remove the negative terminal from the battery, unscrew everything with a key to "10". We remove it and put it aside, you can simply lift it above the terminal.

If the car continues to work confidently, the headlights are not dim, then your generator is 100% working. If the car immediately stalled, it means that the generator is 100% not working and you urgently need to watch it. So I checked it on the VAZ 2101 and now it works on my AVEO.

Battery recharge

However, it is often not "undercharging" and "overcharging" that goes on.

If there is a suspicion of a malfunction of the generator, the car owner first of all seeks to identify the breakdown on his own. There are several verification methods that involve measuring both the removed and the non-dismantled device. Verification in both cases will be valid. In addition to the fact that you need to know how to check the generator, you need to find out the reasons why it may fail. Although the generator is a fairly reliable device, improper or negligent use of the car can damage it prematurely.

For what reason can the generator fail?

Since the symptom of a generator malfunction is almost always the same, it is impossible to immediately identify the reasons why it failed without special equipment. There are 4 main breakdowns due to which the generator can lose its performance.

1. Seizure of bearings... During the operation of the machine, there is a constant movement of elements in the generator, which leads to the disappearance of lubricant and further wedging or complete jamming of spare parts. Since the bearings have a high density, the belt, which is responsible for their rotation, breaks first of all. If the belt is torn, then you should think about replacing or rebuilding the generator.
2. Burnout of the winding... A burned-out winding can occur for various reasons. The most common is the ingress of chemicals and salt that is sprinkled on roads in winter. After the wiring has burned out or simply lost its integrity, current generation stops.
3. Worn or jammed brushes... Problems in the brush assembly arise from worn out graphite rods. This is a fairly common problem, since many motorists forget to replace the brushes in a timely manner.
4. Damage to the regulator relay... This part prevents overcharging of the battery and brings the voltage to the specified parameters.

Since it is not always convenient to check the generator on a machine in the field, it is worthwhile to carry out scheduled maintenance in advance and not neglect the symptoms of an imminent failure.

Check features

You need to know how to check the operation of the generator on a car correctly, otherwise you may be faced with the fact that a serviceable part will be completely disabled. By following just a few simple rules, you can avoid unexpected breakdowns.

1. The check should be carried out with a multimeter.
2. When diagnosing the state of the valves, the current should have a voltage not higher than 12 V.
3. If you need to replace the wiring, you need to pick up wires of the same cross-section with the original ones.
4. Before you start checking the generator, you need to make sure that all fasteners are connected correctly and that the belt is tensioned (read more about). If necessary, the connections are brought to a functional state, and the belt is tightened or loosened.

The main condition under which it is possible to check the generator at home is to maintain its operational state. If the device is disassembled or has received damage that prevent it from functioning, then the diagnostics will not allow us to find out the suitability of the device for further operation.

There is a list of actions that absolutely cannot be performed when checking:

• the performance check should not be carried out by means of a short circuit or, in other words, "for a spark";
• connect terminals of different configurations to each other, and also connect terminal 30 or B + to ground;
• diagnostics and operation of the generator should not start without connecting consumers. It is especially important to observe this point when the battery is disconnected;

How to check the generator for operability at home

There are two main verification methods. One of them, although very old, but reliably allows you to understand the performance of the device. The second works more subtly and is able to respond to minor flaws in the system. Using the second method, you can identify the slightest deviations in the work of each element.

How to check a generator on a car without removing and having the right tool

There is an ancient way to troubleshoot a generator malfunction. It is very simple, but the result can only be two points:

• works properly;
• there are malfunctions.

Since everyone can check a car generator at home in this way, its popularity is fully justified. It is necessary to start the engine and turn on the dipped beam. The negative terminal must be removed from the working engine. If the headlights are on evenly, and the engine stroke is not lost, then the generator is working properly. In case of uncertain operation of the internal combustion engine or a change in the brightness of the headlights, it is necessary to perform a deeper diagnosis, since the device is in a malfunctioning state.

How to check the generator with a multimeter

Measurement with a special device will reveal even a small malfunction. There are a number of indicators that are considered optimal for all types of machines. The battery without load has a voltage in the range of 12.5 - 12.7 V. Since the load is imposed on the battery when the motor is started, the normal indicators are 13.8 - 14.8 V. After reaching the maximum load, the voltage indicator should drop to mark 13 ,eight. If this did not happen or the voltage dropped even lower, then a generator check will be required.

Since not all motorists can correctly ring the generator, if a malfunction is detected, but if it is not possible to diagnose it yourself, it is better to contact the service center. Experienced craftsmen will be able to suggest the causes of the breakdown and explain why it was not possible to carry out the research on their own.

Checking the voltage regulator

The sequence of actions is as follows.

1. To check the condition of the voltage regulator, you will need to use a voltmeter, the scale of which should have from 0 to 15 V. Diagnostics should be performed only on a well-heated motor. To do this, the car is started for 15 minutes and the headlights are turned on.
2. The measurement is carried out between the ground terminal and terminal 30. For most cars, the norm is very easy to find, since most of it is in the range of 13.5 - 14.6 V. Figures below 13 V indicate that parts need urgent replacement.

This method is one way to test a generator without a machine. Diagnostics will require access to the battery and the device itself. The voltmeter is used in measurement mode and is connected to ground and the B + terminal on the battery. After turning on the special equipment in its window, the indicator should not exceed 0.5 mA. If the indicator is higher, then this indicates that the diodes are out of order or the integrity of the insulation on the windings has been violated.

Checking the recoil current

This check is carried out only when the motor is connected. This method is quite problematic and requires a lot of time and scrupulousness. The essence of diagnostics is to measure the current of devices that consume electricity. The engine must be started and at the highest possible speed. The probe is installed on a wire that goes to terminal 30 or B +.

One by one, you need to turn on all the electrical appliances of the car, and record the readings from the multimeter. After the results have been obtained, the numbers must be added. Next, you should turn on all electrical appliances and compare the indicators on the measuring equipment with the sum of past studies. It is considered normal that an indicator is 5 A less than the amount received, but an increased one indicates a malfunction of the spare part.

Checking the generator excitation current

The engine must operate at the highest possible speed. The multimeter is connected to terminal 67. The device will immediately show the result and the magnitude of the excitation current. For a normally operating generator, this indicator is in the range of 3 - 7 A.

Checking the windings

You can check the condition of the winding not only visually, but also with the help of special devices. This manipulation involves carrying out preparatory work:

• dismantling the brush holder;
• removing the voltage regulator;
• stripping slip rings;
• checking for defects in the winding.

How to check the generator for operation? Self-check and repair of the generator

The generator is a typical power plant that provides energy to all engine systems: power supply, cooling, ignition, therefore its failure will inevitably entail other malfunctions. To prevent damage, you need to systematically diagnose it, and if problems could not be avoided, repair it immediately.

In this article, we will talk about how to check generator on efficiency without resorting to the help of professionals. But before that, let's look at the symptoms of its probable defects.

The main symptoms of a generator malfunction

The fact that the generator is out of order, or there are problems in its operation, will be prompted by the following signs:

• constant burning of the warning lamp in the form of a reddish battery on the dashboard, which indicates that the generator is not charging, or is producing insufficient current;
• constantly discharging battery;
• interruptions in the operation of electrical equipment (lighting and signaling units, multimedia, heating and ventilation) when the engine is running;
• the appearance in the cabin (engine department) of the corresponding burnt aroma;
• excess heating of the generator stator;
• roar (rustle, whistle) of the generator.

The appearance of similar signs is a harsh reason for diagnosing. To do this, it is absolutely not necessary to go to a service station, because verify The generator can be fully operational on its own, especially if you have at least the slightest ability to appeal with an auto tester. But first, let's talk about the main breakdowns.

Major malfunctions

The generator can have malfunctions of both mechanical and electronic nature. These include:

• failure of the voltage regulator;
• malfunction of the diode bridge (rectifier unit);
• short circuit of the rotor field winding;
• short circuit of the stator windings;
• wear of brushes;
• bearing wear.

Read

Checking the voltage regulator

The regulator is designed to stabilize the generated voltage before supplying it to the vehicle's on-board circuit, including the battery for recharging it. It is possible to find its serviceability without the help of others in another way, how to check the charging of the generator, more precisely, the magnitude of the voltage supplied by it to the battery terminals. Depending on the make and model of the machine, it can be from 13.5 to 15.5 V. Therefore, before checking the operation of the generator for the serviceability of the regulator, you need to find out exactly what voltage it should give out. This information can be obtained from the vehicle's operation department.

How to check the generator multimeter? To do this, switch the device to the voltmeter mode and, observing the polarity, connect its probes to the battery terminals when the engine is not running. The voltage is considered normal within 12-12.8 V. Then start the motor and repeat the procedure. The voltage at the battery terminals should rise to 13.5-15.5 V. Only in this case, the regulator can be considered operational. An increase or decrease in the voltage value, on the contrary, indicates that it is faulty.

How to ring the generator brushes VAZ 2107 VAZ 2106

How to call generator brushes VAZ 2107 VAZ 2106.

Checking brushes for resistance

Examination brushes resistance to receive charging from someone who does not have it, brushes you can measure any.

How to check the diode bridge of the generator without removing it from the car

The diode bridge acts as a kind of rectifier, converting the alternating current generated by the generator into direct current. Usually it consists of six semiconductor diodes, three of them are positive, the other three are negative, that is, the first pass current in one direction, the second in the other. The rectifier can be checked both with the generator removed and without dismantling it. Let's consider both options.

Before checking the diode bridge of the generator without removing it, it is necessary to disconnect all wires from it and from the voltage regulator, having previously disconnected the ground terminal from the battery. First, let's check the rectifier for a short circuit. We turn on the multimeter in ohmmeter mode, connect the positive (red) probe to terminal 30 of the generator (positive contact of the bridge), and the negative one to the generator case. In a working rectifier, the readings of the device will tend to infinity. If the resistance is several ohms, the rectifier is faulty.

Now let's talk about how to check the generator diode bridge for breakdown. Let's start with positive diodes. Again, we connect the positive probe to the corresponding contact of the bridge (pin 30), and the negative one to the bolts (brackets) of the rectifier. At the same time, resistance should also tend to infinity. Otherwise, one or more diodes are broken.

Moving on to negative semiconductors. We attach the red tester probe to the rectifier mounting bolts, the black one to the generator case. Resistance tending to infinity is a sure sign that the diodes are intact.

Checking the rotor winding

Read

A common fault in a car generator is a winding short circuit. This can happen as a result of a sharp voltage surge, water ingress, wear of brushes, etc. Since it is possible to check the generator with a multimeter for the integrity of its windings only after gaining full access to them, the entire assembly will need to be dismantled. We will not describe this process, since it is different for different cars. Before checking the removed generator for the operability of the rotor winding, it is naturally necessary to disassemble it.

After removing the rotor, we find slip rings on its shaft. There are only two of them. Turning on the multimeter in ohmmeter mode, connect its probes to these rings. The device should give a resistance in the range of 2-5 ohms. These are normal values ​​for a good rotor. Higher resistance indicates poor contact between the rings. In the opposite case, when the readings of the device approach zero, most likely there is an inter-turn short circuit.

How to check the generator for the operability of the stator windings

Moving on to the stator. It has several windings, each of which must be checked separately. But before that, it is imperative to disconnect the wires connecting the winding leads and the diode bridge.

The probes of the multimeter, turned on in ohmmeter mode, are alternately connected to the terminals of each of the windings. The working winding should have a resistance of about 0.2 ohms.

Alternator brush wear

If the generator has already been dismantled and disassembled, it does not hurt to check the condition of the brushes. They can fail due to long-term use, or as a result of problems caused by the skewed rotor shaft. If the brushes show signs of great wear, their geometric shape is disturbed, they must be replaced.

Alternator bearing wear

The car generator has two bearings. One of them is fixed on the rotor shaft, the second is pressed into the central part of the cover. The hum, the whistle coming from the generator while the engine is running, is a sure sign that some of the bearings ordered to live long. A concomitant symptom may be heating of the generator housing. Having found these signs, hurry up to replace the bearings. Otherwise, this will lead to a misalignment of the rotor shaft or its jamming, with all the ensuing consequences.

How to check spark plugs Before delving into the background of spark plug defects, I suggest that you first remember their design and purpose. A spark plug is a device designed to forcibly ignite a working consistency in a combustion chamber. They are used in internal combustion engines with external mixture formation (carburetor engine). Arson g ...

A car generator is one of the most important components in a car. He is responsible for the supply of energy, is a backup source, takes on huge loads in the event of a network failure, because you cannot go far with one battery. A caring motorist is obliged to periodically check the operation of the generator, monitor its condition. From the article, you will learn how to test a generator using a light bulb and in other ways.

Lamp test

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A lamp test is a test of the generator using a "fog lamp". The task of diagnostics is to determine if the generator rotates correctly when the drill speed is applied to it. The light bulb in this case plays the role of an indicator - if the generator rotates normally, then it (the light bulb) should light up.

It is important to know that a working generator should deliver a voltage within 14.1-14.5 V. And at the same time, the voltage should not jump, have drops. In other words, the voltage must be stable.

To carry out this type of testing, the autogenerator will have to be dismantled from the car, and the following steps must be taken:

• clamp it in a vice so that it is convenient to work;
• integrate a battery with the generator.

We also advise you to find out the type of generator before diagnostics. As you know, they are different in terms of connection. It means that the units may have a different number of contacts. A distinction is made between 2-pin, 3-pin or 4-pin generators.

4-block generators contain the following contacts:

• plus of the constant type, marked by the Latin S;
• plus associated with ЗЗ - IG;
• contact for the control unit marked with M;
• for the control lamp - L.

We continue a series of actions:

• a positive cable is drawn from the storage battery to both "+" dynamos;
• a lamp with a value of 50 W is integrated to the desired contact;
• voltage is applied to the lamp;
• the generator rotates with a drill;
• the indicator glow is tested.

So, if the light bulb shines brightly and the voltage on the dynamo is within the normal range, then the generator is completely serviceable. In any case, it is capable of recharging the battery.

The connection between the generator and the battery is an important tandem. Under no circumstances should the battery be disconnected while the car is running! Ask why? This puts unnecessary stress on the voltage regulator and generator, causing a failure in the overall system. This can even be seen from the indicator: if the lamp under test is disconnected from the battery, then with a working dynamo it will continue to glow, but the voltage will no longer be stable.

You can not disconnect the battery also because of a banal short circuit. KZ will burn not only the unit itself, but also the electronic units installed in the car.

So, the rule is not to throw off the terminals with the battery under any circumstances, it must be knocked out into the list of the main canons of the motorist. Those who like to “light up” the battery do the wrong thing, which often happens in the winter season. Keep a charger in your car and don't tempt fate. Once, another lucky, and on the third you can burn the entire electrical system.

Checking the unit piece by piece

The generator is, in fact, legally tested piece by piece. For example, most experts agree that a light bulb test gives only 95 percent diagnostic accuracy. Indeed, it is so.

In order to fully check the generator, it is necessary to diagnose the unit in parts.

The stator is checked first. It is tested separately as soon as the generator is disassembled. The stator is decoupled from all native resistors and semiconductor devices to ensure accurate testing results.

Diagnosis is carried out as follows:

• The insulation of the winding wiring is examined, which should not have traces of overheating or melting (which is many times worse, since it indicates a short circuit). If traces of overheating are found on the part, then the stator is replaced with a new one.
• Next, a multimeter is taken, which is put in the ohmmeter measurement mode. The generator is checked for breaks in the winding or for a short circuit.
• Resistance is tested. To do this, you need to connect the probes, adhering to the scheme of alternating connection to the ends. The impedance between them should be two to three tenths of Ohm.
• A multimeter is used to test whether the electrical winding is short-circuited to the case. To do this, one of the probes of the device is connected to the stator housing, and the other to each of the winding leads. It is short in the event that the multimeter emits a sound in the buzzer mode. Again, the blame becomes the stator, which has to be changed.

It often happens that the cause of the short circuit is in the winding wires. Any of the wires may be slightly exposed and touch this part of the case. The problem is solved simply - this part of the wire is bent and covered with insulating varnish. However, in most cases, it is more difficult to determine the short circuit of the winding, since the problem area is not visually visible.

The next part of the generator to be tested is the rotor. Its electrical PP winding is being tested. It is easily diagnosed even when the generator is not removed. It will be enough to dismantle only the relay-regulator with the brush block, and then connect the tester to the copper contacts. However, for the most part, specialists test the rotor independently of the generator.

As in the case of the stator, the probes of the meter, brought to the Ohm measurement mode, are connected to the rotor contacts. The normal value of the ohmmeter should be in the range of 2.5-5 ohms if the generator model is 500-1200 watts.

With smaller or larger values, a diagnosis is already made: either an interturn short circuit, or a poor connection of the winding terminals with the contacts.

Attention. If the device shows zero resistance at all, there is definitely an open circuit in the rotor winding.

Semiconductor diode device (WB)

WB or diode bridge is also checked without fail. A suitable diode, as you know, is obliged to pass the voltage limited, that is, along one line. As for the faulty diode, it does not react to voltage in any way, or it does so on both lines, which leads to a short circuit.

The entire diode bridge is replaced, as a rule, if at least one of the diodes is out of order. The fact is that they (diodes) are pressed into the plate. Removing and changing one of the diodes can be oh, how difficult, so you have to change the entire unit.

• the presence of a short circuit in the diode bridge can be determined without removing the generator from the car;
• before checking, it is recommended to disconnect the generator wiring and remove the battery terminals;
• testing can be carried out not only with an ohmmeter, but also with a test lamp;
• three VB diodes are called positive, since they are connected to the "+" of the rectified voltage, and the other 3 are negative, since they have "-" on the case (both 3-diode groups are pressed into a separate track made of soft metal, integrated either with mass or with the 30th current output of the generator).

So, the check is carried out as follows:

• First, the presence of a short in the positive 3-diode group is tested. To carry out such an operation, a positive voltage is drawn from the battery through a light bulb to the generator terminal at number 30. The negative terminal of the battery is connected to the generator frame. In such a scheme, if the indicator (light bulb) is on, then there is a short circuit in the group.

• The presence of a short circuit in the group of negative diodes will also be indicated by the glow of the light bulb. However, the connection diagram is slightly different. From the battery, the positive cable is connected to one of the generator retaining screws. An indicator light cuts into the wire. The minus from the battery also goes to the case.

The glow of the indicator may also indicate problems with the stator, but most often this indicates a short circuit of the diodes.

Breakdown in resistors can also be detected using a measuring device. It should be an oscilloscope. It is also possible to check the presence of a short circuit at the stand - in this case, a decrease in the value of the supplied voltage by 20-30 percent will indicate problems.

And, of course, you can test the breakdown in the diode bridge through a multimeter set to ohmmeter mode. One of the terminals of the device is connected to a positive or negative plate (positive or negative group), while the other is alternately touching the terminals of the diodes. Then the probes are swapped.

The problem can be judged if there is no conductivity (in other words, if the multimeter shows resistance in both directions). Also, the zero resistance of the multimeter indicates the breakdown of the diodes.

Attention. As a rule, if one diode of the group is broken, the battery constantly shows an undercharge.

Additional diodes

Testing the booster diodes is also an essential part of testing a generator piece by piece. They (additional diodes) are installed on all modern cars, including domestic VAZs of a new type.

To test the short circuit on auxiliary diodes, it is not at all necessary to dismantle the entire unit. It is just important not to forget, before checking, remove the terminals from the battery and disconnect the wiring.

So, the connection is carried out, as in the diagram above. Plus from the battery goes to the 61 output of the generator, and in the middle a 1 or 3-watt indicator light is cut in the middle (number 2 in the diagram). The negative wire goes to one of the generator mounting bolts.

The closure is judged by the glow of the light bulb. If it is on, then a short circuit is observed in one of the additional diodes.

The test can be carried out without removing and disassembling the generator, however, in order to identify which particular resistor has failed, you should dismantle the rectifier and test each of the components separately using a measuring device.

Additional resistors can be tested using various meters. For example, it could be a voltmeter. If the voltage on it shows less than 14 V, this is a clear breakdown.

Battery

Checking the generator, in most cases, is caused by the illumination of Control Ind on the dashboard. However, this does not at all prove that the generator is faulty. The indicator signaling on the "tidy" may indicate a battery malfunction.

Why does the battery lose its charge? Isn't this a consequence of the generator output? Of course not. This can be caused, for example, by damage to the regulatory relay.

We learned that the generator can be correctly tested not only with the help of a light bulb, but also in other ways. It is best to check the unit separately, because it is precisely such diagnostics that give a full-fledged result.

The main source of electricity in a car is the generator. It starts simultaneously with starting the engine, after which it generates energy and charges the battery. If it fails, the battery charge will not be enough for the long-term operation of the car, so the driver is obliged to monitor the condition of the generator.

There are a lot of problems due to which the generator can fail during operation. These can be both mechanical and electrical problems. A generator malfunction also manifests itself in various symptoms, among which the most common are:

• The appearance of extraneous sounds emanating from the generator;
• Battery problems: discharging, overcharging, boiling off the electrolyte;
• Reducing the brightness of the headlights with increasing revs. This situation is considered normal if it occurs for a short time when switching to first gear from idle on a "cold" engine;
• Warning lamp signaling about the discharge of the battery while the car is moving;
• Electronic malfunctions, including dim headlights and weak beeps.

If the symptoms described above occur, the vehicle's alternator should be checked. Diagnostics, most often, is performed according to four parameters:

• Checking the recoil current strength;
• Diagnostics of the diode bridge operation;
• Checking the generator voltage regulator;
• Excitation winding check.

Depending on the identified problem during the diagnosis, the issue of the expediency of repairing the generator is resolved.

Generator Inspection Safety Rules

Before you start checking the car generator, you should familiarize yourself with the basic safety rules that will allow you to preserve the health of the diagnostician and not damage the unit. The basic rules for the safe inspection and repair of a generator are as follows:

Please note: If not only the generator is being checked, but also welding work on the car body, it is necessary to disconnect the generator and the battery completely from the vehicle's on-board network before starting them.

Checking the generator recoil current

For this generator check, you will need a multimeter equipped with a special probe to measure the current flowing in the wire. This probe looks like a clamp that wraps around a wire, and most often it comes with a diagnostic device. To check the generator recoil current, you need to:

1. Put the clamp on the wire that fits the contact "B +" ("30") of the generator;
2. Next, start the engine and set high revs;
3. After that, one at a time, it is necessary to turn on the electrical consumers on the car - a radio tape recorder, air conditioning, steering wheel heating and others. When each consumer is turned on, readings from a multimeter should be recorded;
4. Next, you need to measure the recoil current when all consumers are turned on together (which were included in the previous test).

When all measurements are obtained, it is necessary to compare the total indicator of the alternate switching on of consumers and the indicator of instantaneous switching on of all consumers. It is considered unacceptable if the indicator, upon instantaneous switching on of all consumers, is 5 or more Amperes less than the sum when switched on alternately.

Checking the diode bridge of the generator

To check the condition of the diode bridge of the generator, you must put the multimeter in the alternating current measurement mode. Connect one test lead of the diagnostic tool to the "B +" ("30") output, and the other to ground. The voltage with such a connection of the probes should be no more than 0.5 volts. If the voltage is higher, the diodes are likely to be short-circuited.

You can also check the diodes for breakdown. To do this, disconnect the battery from the generator and also disconnect the wire that goes to the "B +" ("30") terminal. Next, the multimeter is connected between the disconnected generator wire and "B +" ("30"), after which readings are taken. If the discharge current of the multimeter shows more than 0.5 mA, there is a high probability of diode breakdown.

Checking the generator voltage regulator

To diagnose the condition of the car generator regulator, you must use a voltmeter or multimeter in voltmeter mode. Before starting the measurements, you need to start the engine, turn on the headlights and let the engine run for 15-20 minutes. The measurement itself is carried out with probes, which are connected between the ground and the "B +" ("30") terminal of the diagnosed automobile generator. The obtained values ​​are recorded, after which they must be compared with the normal figures for a particular car model. These figures can be found in the technical documentation of the machine. For most machines, the normal voltage ranges from 14 to 16 volts. If there are deviations from the standards set by the car manufacturer, there is a high probability of failure of the voltage regulator, in such a situation it will need to be replaced.

Excitation winding check

To check the serviceability of the excitation windings of the automobile generator, it is first necessary to remove the regulator and the brush holder in order to gain access to the slip rings. For diagnostics, an ohmmeter is required, the probes of which should be applied to the slip rings of the generator. As a result of the test, the resistance should be at a level of 5-10 ohms. You also need to make sure visually that there are no breaks in the winding.

To diagnose the short circuit of the excitation winding "to ground", you will need to connect one ohmmeter probe to any slip ring, and attach the second to the generator stator. As a result of the measurement, infinite resistance should be displayed on the screen.

When diagnosing the generator, it is also necessary to inspect it for mechanical damage. Based on the results of all checks, the expediency of repairing the device or replacing it with a new one is determined.