Signs of a malfunctioning generator and how to eliminate them. Generator

The electrical equipment of the car fails quite often, so auto repair shops usually put such malfunctions in a separate category. In most cases, the problem lies in the breakdown of energy sources or the failure of current consumers. The sources are batteries and generators, and the consumers are headlights, ignition, air conditioning, etc.

If the battery or alternator is not working, you will not be able to use the vehicle normally. As a rule, the car cannot move at all. If one of the sources of electrical energy in the car fails, expect problems with the other.

A simple example: the destruction of the battery will increase the charging current of the generator. In the end it all ends in failure. diode bridge.

Another option: if the voltage regulator that the generator produces fails, the charging current very often increases. This, in turn, causes the battery to be regularly recharged, causing the battery to rapidly degrade.

Common battery problems

As a rule, motorists are faced with the following battery malfunctions:

plate damage (chemical or mechanical);
short circuit of the plates or electrodes of the battery;
damage to the battery case, due to which the battery banks lose their tightness;
chemical oxidation of the terminals at the battery terminal.

In most cases, battery failures occur for the following reasons:

Battery misuse.
End of battery life.
Manufacturing defects.

It's time to go directly to . Generator breakdowns are much more common, which is caused by the more complex design of this element. Yes, and finding problems can be much more difficult.

Specialists often deal with such generator malfunctions:

failure of the voltage regulator;
damage to the diode bridge (aka rectifier);
wear of current-collecting brushes;
defects in the wires of the charging circuit;
damage or operational wear of the pulley;
wear of slip rings or collector;
short circuit of individual turns on the stator winding;
bearing failure.

Every self-respecting motorist should understand what causes of generator malfunctions are most common, and how they can be dealt with. It is also necessary not to forget that timely prevention helps to avoid serious problems. Towards the end of the article, we will also look at some tips that will help you learn how to test the generator yourself. But let's first learn about the inner workings of a node.

There are constant and alternating current. In our time cars are equipped with AC devices with an integrated rectifier, which is also called a diode bridge. It is this part that ensures the conversion of alternating current into direct current, which is necessary for the functioning of electrical devices in the car. In most cases, the diode bridge is located in the generator housing or cover. As a rule, it is built into one of these parts.

The electrical equipment of a modern car can only operate in a given range of voltage currents. Very often, the working voltage is considered to be from 13.8 to 14.7 Volts. Since the generator is connected to the engine crankshaft using a special belt, its operation directly depends on the speed of movement. vehicle and current engine speed.

In order to smooth the received current, a voltage regulator relay is used. In fact, it is used as a stabilizer and helps to equalize the operating voltage, in which there should be no dips and jumps. Many automotive alternators are equipped with integral-type voltage regulators, which motorists call “pills” or “chocolates”.

Generator fault classification

Since the car generator is an electromechanical device, its main malfunctions are divided into two categories - electrical and mechanical. Electrical faults are breakdowns of the diode bridge, interturn short circuits, damage to the windings, breakdown of the relay-regulator, burnout of the brushes and their wear, as well as breakdowns.

But mechanical malfunctions include damage to fasteners, problems with bearings, destruction of the generator housing, disruption of the correct operation of the belt drive, and other malfunctions that have nothing to do with the electrical “stuffing” of the generator.

Very often, the signs indicating a breakdown of the generator are caused by completely different problems that appeared earlier. For example, a generator malfunction may be the result of burnt contacts located in the ignition lock housing. Sometimes the light, indicating that the generator is not working, is on due to a broken relay.

Typical signs of a malfunctioning generator in a car:

The battery is being recharged or .
When the engine is running, either lights up.
A significant increase in the brightness of the headlights with an increase in speed. This can happen during regassing after idle move, however, the brightness of the headlights cannot increase continuously.
The sound signal is too weak, the headlights are not bright enough when the engine is running.
The presence of specific sounds that the generator makes.

Troubleshooting Methods

Many motorists are accustomed to checking the generator with old methods that are forbidden to use on modern cars. For example, some "garage" masters advise to throw off the terminal from the battery. Such a solution can cause the failure of various car electronics, so it's not worth the risk.

Diagnostics of generators today is carried out by determining the voltage in the mains or checking the device using special equipment. At the first stage, the specialist determines the voltage at the battery terminals. Then he starts the engine and performs a measurement already on the running engine.

With the engine turned off, the voltage should be approximately 12 volts, but after starting the unit, the indicator should reach 13.8-14.7 volts. If the voltage is higher, this is a sign of "overcharging", which is caused by a breakdown of the relay regulator. If there is a downward deviation, no current is applied. The reason may be the failure of the circuits or a malfunction of the generator.

Causes of malfunctions

As a rule, the main causes of generator failure are the appearance of corrosion processes and normal operational wear. Almost all mechanical failures are the result of prolonged use of the unit. In new cars, alternators are equipped with closed-type bearings, which periodically need to be replaced. The same applies to the electrical component of the device - often they just have to be changed as an assembly.

Additional factors that cause breakdowns:

poor quality of parts;
abnormal operating conditions;
exposure to elevated temperatures, salt, dirt, liquids and road chemicals.

Do-it-yourself generator check

The simplest option for those who do not know how to check the generator is to inspect the fuse. If the element works, go to the generator itself. It must be checked that the belt is not broken, the rotor rotates freely, and the housing is not damaged. Next, the diagnosis of slip rings and brushes is carried out. Brushes need to be changed periodically. If you notice too much sparking, this indicates the need to purchase new generator brushes. Sometimes malfunctions of the autogenerator are caused by the failure of the stator.

Experts note that most often bearings break from the mechanical components of the generator. You can determine their wear by the characteristic whistling sound during the operation of the generator. Worn bearings must be replaced without fail. Sometimes the alternator does not work efficiently because the drive belt is too loose. Very often this appears during acceleration of the car.

Diagnostics of the rotor field winding is performed using a multimeter. On the device, select the resistance detection mode and connect it to the contact rings of the unit. The resistance should be in the range of 1.8-5 ohms. If you see lower readings, there is a short circuit in the coils. If the indicators are higher than the mentioned values, the winding has broken.

To check the generator stator windings for a "breakdown to ground", we disconnect them from the rectifier unit. If the multimeter displays resistance readings with infinitely large parameters, there is no normal contact of the windings with the case (i.e. "ground").

The diodes in the rectifier unit are also tested with a multimeter (we first disconnect them from the stator windings). Select the operating mode "diode test". The red probe should be connected to the “+” or “-” of the rectifier, but the black probe (negative) is connected to the phase output.

Then the probes should be swapped. If, when performing such a procedure, the readings of the device differ significantly from the previous ones, the diode is working normally. If there are no differences, the diode is out of order. A malfunction of the diode bridge of the generator is also confirmed by the oxidation of the contacts as a result of overheating of the radiator.

Generator repair and troubleshooting

Breakdowns of a mechanical type are “cured” by the banal replacement of inoperative components with new or working ones. On older generators, slip rings are often machined. Alternator drive belts should be replaced if they break, stretch excessively, or show visible defects. Rotors and stators, the windings of which have been damaged, are recommended to be changed, since almost no one is engaged in rewinding.

The generator is one of the most important components of any car, the breakdown of which is guaranteed to immobilize your vehicle in just a few tens of kilometers. Any malfunction of this part requires immediate attention. Otherwise, the car often faces costly repairs. It is important to notice and eliminate the malfunction of the generator in time. We counted seven breakdown symptoms that will help you in this difficult task.

Generator device

Before talking about the symptoms of a breakdown, it would be useful to recall how the alternator works and functions. This part consists of an aluminum housing, inside of which there is a stator coil and a rotor on bearings. The rotor shaft is driven by a drive belt from crankshaft engine. The alternating current taken from the stator winding is converted into direct current by a powerful diode rectifier. Carbon brushes transmit control current to the rotor from the voltage regulator. Thanks to its operation, the generator constantly produces about 13.8–14.7 volts at the output, regardless of engine speed. This current is used to power the on-board network of the car and serves as a source of recharging the battery. A breakdown of the generator or its incorrect operation leads to a rapid discharge of the battery or its complete failure, as a result, the machine is de-energized and loses the ability to move independently in space.

Generator malfunctions

All generator malfunctions can be conditionally divided into two groups - mechanical and electrical. The first includes the destruction of the body of the device, breakage of fasteners, bearings, clamping springs of brushes, overrunning clutch or pulley and other parts, and the second - breaks and short circuits of the winding, breakage of the diode bridge and relay-regulator, wear of carbon brushes. There are several common signs of impending trouble with the generator - these are dim or flickering headlights, problems starting the engine and a wink or constant burning of the control lamp on dashboard.

The car's battery and alternator work in tandem. At the same time, it is the generator that is the main source of power for the electrical network, while the battery acts as a backup source of energy and is needed primarily to start the engine and power electronic devices with the engine not running.

Generator malfunctions manifest themselves in different ways, but in most cases they do not come suddenly; the driver has time to notice the impending breakdown and minimize trouble.

Difficulties when starting the engine

One of the sure signs of a generator failure is an uncertain start of the car engine. When the alternator stops working correctly, the battery loses its charge and loses its ability to crank the starter normally. A discharged battery is usually a direct consequence of a broken alternator. In this case, the battery can not only receive less charge, but, on the contrary, be recharged.

This happens due to a breakdown of the electronic unit of the relay-regulator: the generator produces more current than required, and this leads to the boiling of the electrolyte and the rapid failure of the battery. Note that many modern cars stop starting when the voltage in the on-board network drops below 12 volts. In this case, the battery is able to scroll the starter.

Dim or flickering headlights

The second symptom becomes noticeable at night. The vehicle's headlights dim or dim depending on engine speed and load on the electrical system. This behavior of the lighting fixtures clearly hints that it is urgent to revise and diagnose the generator and its drive belt - the device cannot cope with the load assigned to it. Also, problems can be noticed by the backlight of the dashboard and interior lighting devices - they all change brightness in the same way.

The icon on the dashboard is on

A lit or flickering battery icon on the dashboard indicates that your car has a serious problem - the battery is not charging properly. The on-board system independently warns the driver that the car will not pass for a long time. As a rule, we are talking about several tens of kilometers - the car will be able to drive smoothly until the battery is completely discharged and stops sparking on the spark plugs. In such a situation, much depends on the condition of the battery itself, as well as on the number and power of consumers involved. Try to turn off everything unnecessary, including music, headlights, electric heating and even interior ventilation, and go to the nearest car service or turn off the engine and call a tow truck. Many modern batteries become completely unusable after the first deep discharge, which means that the services of a tow truck can pay off.

Whistling drive belt

Often, an unpleasant whistle is heard from under the hood of an unheated car. It occurs if the drive belt that drives the generator rotor is loose. It is necessary to establish the cause of the weak belt tension and eliminate the malfunction. Otherwise, the generator will not rotate at the proper speed and charge the battery normally. On many modern vehicles, this same belt drives other devices, such as the power steering pump and air conditioning compressor, and tensions automatically. On simpler models, the auto-tensioner is not provided for by the design - over time, the belt stretches and requires manual tension adjustment.

Belt overheats or breaks

A characteristic smoke and an unpleasant odor emanating from the drive belt, or detachment of tracks and pieces of rubber from it, is a sign of wedging of some mounted unit (including a generator) or bypass rollers. On some models, a broken drive belt not only turns off the generator, but also causes much more serious troubles (scraps can get under the timing belt, which will lead to a violation of the valve timing or engine breakdown). If the belt overheats or spontaneously breaks, check the alternator pulley - it should rotate easily and not warp under load.

Ringing or rustling sound from under the hood

Rolling bearings are installed inside the generator. These parts are subjected to high loads and operate at elevated temperatures. Their resources are relatively small. After some time, these parts wear out and lose lubrication, which leads to noise, misalignment and wedging of the rotor, or complete destruction of the bearings. Another cause of noise can be a worn freewheel or damper clutch. It also works for a relatively short time, can be deformed and cease to fulfill its function. Both malfunctions cannot be eliminated without removing and disassembling the generator.

electric hum

The nature of extraneous sounds becomes somewhat different in the event of a short circuit in the stator winding. It manifests itself with a characteristic electric howl, similar to that which comes from the electric motors of public transport - trolleybuses, trams or electric trains.

Going on a long trip, especially to sparsely populated and hard-to-reach places, make sure that your car's generator is in good condition. Its breakdown is no less insidious than a gearbox malfunction or a broken timing belt. You simply cannot solve the problem on your own on the road without a special tool, spare parts and experience. Therefore, make it a rule to carry out troubleshooting and repair of the generator with removal from the car at least once every 100 thousand kilometers. You can do this yourself, but it is much more convenient and faster to use the services of special firms. The help of professionals in this matter will not be superfluous.

October 19th, 2016 Admin

Among car breakdowns, the most common failure of electrical equipment. All electrical equipment can be divided into current sources, current consumers and auxiliary devices. Current consumers include optics, ignition, climatic equipment, anti-lock wheel system, security systems, lighting fixtures and other equipment. All of these systems will not work without trouble-free operation of power supplies.

As a power source in passenger cars, a three-phase alternating current synchronous generator is used, which is driven from the main engine. Its power is 700-1000 watts. The automotive industry switched to installing alternators on cars (it used to be DC generators) when powerful diode rectifiers appeared. This made it possible to reduce the weight of the node by a factor of three. Some consumer systems (car radio, anti-theft system, brake lights, lighting, and others) must also work when the engine is off. Their continuous operation is provided by a car battery. It is charged from a running generator, smoothes out voltage drops during the connection of energy-intensive consumers.

It is impossible to understand the malfunctions of the generator without knowing what it consists of and how it works.

Automobile generator - device and principle of operation

A three-phase diode rectifier and a voltage regulator are built into the body of modern generators. Below we will look at how a car generator works.

Pulley transmits rotation by means of a belt drive from the motor output shaft to the rotor.

Rotor- this is the generator shaft, to which rotation is transmitted from the engine. Two beak-shaped steel bushings are mounted on it, between which there is an excitation winding. The output contacts of the excitation winding are brought to slip rings.

stator is a package of steel sheets assembled in the form of a pipe. There is a three-phase winding in the stator slots. She generates power.

Rectifier block (diode bridge) consists of two heat sinks (positive and negative), each of which is connected to three powerful diodes. The node serves to convert the alternating current of the generator into a direct current, or rather, into a pulsating one with a high frequency, which is necessary for voltage consumers.

Protective cover for diode module

Voltage regulator- a device that maintains a certain voltage change interval, safe and sufficient for the operation of auto current consumers, when the motor shaft speed changes, and hence the rotor, electrical load, ambient temperature.

brush knot- a design that ensures the contact of spring-loaded brushes with the rotor rings. The design is made of plastic, removable.

generator housing unites all its nodes, has output contacts for connection to the electrical system, is mounted on the car engine, consists of two covers.

We have dismantled the device of a car alternator, now we need to figure out how it works.

When the ignition is turned on, the generator rotor is driven by the motor. The excitation winding creates an electromagnetic field that induces electricity in the stator windings. Then the voltage regulator corrects the jumps to 13.8 ÷ 14.2 V. The corrected voltage is supplied to the battery.

The most common generator malfunctions:

pulley damage or wear crankshaft, which transmits rotation from the engine to the rotor;
malfunctions in the brush assembly or wear of the current-collecting brushes;
malfunction of the voltage regulator;
breakdown of the diode bridge;
destruction of the rotor shaft bearing;
violation of the integrity of the wires of the charging circuit or output terminals.
breakage or short circuit of the windings;
contamination of contact rings, including due to burning;

The most common battery failures are:

The car battery is used in the car as an additional power source when the engine is not running and to start the engine. Batteries with a voltage of 12 V are installed in passenger cars. The type of batteries is lead-acid.

electrode damage (mechanical or chemical);
short circuit of the battery plates;
violation of the integrity of the battery case, depressurization of cans;
oxidation of battery terminals.

Types of generator malfunctions

Mechanical failures include malfunction of bearings, mechanical damage to the housing, fasteners, springs, belt drive, pulleys, etc.

Electrical - this is brush burnout, rotor runout, interturn short circuits, diode bridge breakdowns, breakdowns, winding breaks, relay malfunctions, etc.

Signs of a malfunctioning oscillator:

ABOUT possible malfunctions generator should be considered if

the battery discharge indicator lights up or flashes while the engine is running;
the battery has been discharged or boiled away (recharged);
the brightness of the headlights has decreased;
a squeak, howl, and other extraneous sounds come from the generator.

Diagnostics of malfunctions of the generator

Unstable operation of the generator does not provide recharging of the battery. At the moment when the battery is completely discharged, the engine will stall, the car will stop in the most inappropriate place. In order not to get into such a situation, you should periodically check the health of this unit and the battery.

Generator diagnostics should be done only with a voltmeter or ammeter.

During the diagnostics or repair of the generator, the safety regulations must be strictly observed. In order not to ruin the generator when checking, in no case should you:

Check by short circuit, "for a spark". Significant voltage drops are very likely to disable all the electronic systems of the car.
Connect terminal "30" or "B+" to ground or terminal 67 ("D+").
Allow the generator to operate when the battery is disconnected or without load, that is, when there are no consumers turned on.
Carry out welding of the body with the wires of the generator and battery connected.
When turning on the battery, pay close attention to the polarity of the battery. Otherwise, there is a high probability of damaging the rectifier diodes.
When disconnecting the wires of the generator, you should carefully monitor where they are located so as not to accidentally close them together. Careless wiring can damage the generator components.
If it is necessary to replace the wiring, then it can only be used on wires with similar parameters (section and length).

How to check if the generator is working in the car?

It is carried out in the following order:

1) Checking the fuse. If it is not correct, it is replaced.

2) If the fuse is good, inspect the case, its integrity and location. It is necessary to check the rotation of the rotor, the integrity and tension of the belt, whether the wire connections are damaged.

3) Check slip rings and brushes. During operation, the brushes wear out, they can sometimes wedge. Slip rings become dirty over time, their grooves become clogged with graphite dust.

4) Check bearings and stator. Bearing wear is indicated by a howl or whistle during generator operation.

5) The rotor is diagnosed: the excitation windings are checked for breaks and short circuits. The multimeter must be switched to measure the resistance and connected to the contact rings of the generator. If the measured resistance is below 1.8 ÷ 5 ohms, there is a short circuit in the turns. If it is higher than this interval, there is a winding break.

6) To check the excitation windings "to ground", you must disconnect them from the rectifier. If the multimeter gives an infinite resistance reading, then there is no touch stator windings with the body ("mass").

7) Having disconnected the multimeter from the stator windings, it is necessary to transfer the device to the “diode test” mode. The plus of the multimeter is connected to the rectifier terminal, the minus to the phase output. Taking evidence. Then the probes are interchanged. Taking readings again. A faulty diode bridge will have the same readings. If the readings are very different from each other, then the node is working. The diode bridge fails if the contacts are oxidized due to overheating of the radiator.

Why does the generator in the car break down?

wear during operation, corrosion;
installation of low-quality components;
improper operation outside the recommended operating modes;
the influence of external adverse factors (road "chemistry", high temperature, dirt, salt).

Troubleshooting and repair of automotive alternators

Detected worn or defective parts are replaced with new ones. The previously practiced rewinding of the rotor or stator windings is now unprofitable. More often, brushes, bearings, and a belt require replacement. You can easily do it yourself small works. For example, solder the wires cut off from the output terminals. Rinse slip rings with gasoline and dry.

With a simple repair that does not require professional skills and high qualifications of an auto mechanic, you can handle it yourself. It must be remembered that repairs should be approached wisely, not repairing the part that is easier to buy and replace with a new one. After all, the old one will fail faster, and the repair will turn into an endless process.

Obviously, you can independently diagnose the operation of the generator nodes. This requires desire, quite a few tools and time. If there is no desire or time, then you can always turn to an experienced master. The main thing is not to ignore such an important node so that car trips are a pleasure, and not forced to solve new problems.

The generator is traditionally used in all cars with internal combustion engines, and serves to convert the mechanical energy of the engine's rotation into electricity. The device belongs to electrical equipment with a complex design, and its failure leads to battery discharge and even engine failure. To ensure a long service life of the product, it is necessary to follow the rules for its operation, as well as to identify and eliminate emerging breakdowns in a timely manner.

The principle of operation of a car generator

The car generator is designed to convert the rotational energy of the engine into electric current, which is used to power the electrical equipment of the car. The device is driven from the crankshaft by a belt drive. Its main parameters include rated current and voltage, rated speed and self-excitation, as well as efficiency.

When the ignition switch is on, the current from the battery through the brushes goes to the excitation windings, creating a magnetic field there. The rotor begins to rotate simultaneously with the engine crankshaft, and its magnetic field penetrates the stator windings, creating an alternating voltage. The rectifier unit converts the current into direct current, which feeds the battery and the on-board network.

When the load in the network and the engine speed change, the voltage regulator starts to work, controlling the turn-on time of the field winding. If the current consumed in the car exceeds the value generated by the generator, the lack of electricity is compensated by the battery, as evidenced by the charge lamp on the control panel.

General design of the device

Automotive alternators are available in compact and traditional forms, differing in size, housing design, fan layout, drive pulley and rectifier assembly. Moreover, all devices have the following common components:

Frame. Serves to accommodate most of the structural elements of the device. It consists of a front and back cover, interconnected by bolts, which are made of a non-magnetic alloy that easily gives off heat. Ventilation windows are made on the surface and mounting paws are provided.
Rotor. Designed to create a rotating magnetic field. For this purpose, an excitation winding is mounted on its shaft, which is placed in two pole halves. At the end of the shaft there are two slip rings for powering the excitation winding. Most rotors have a fan impeller and a drive pulley on the shaft. The shaft itself rotates on a pair of ball or roller maintenance-free bearings.
Stator. Designed to generate alternating current, and structurally includes a metal core with windings. The core is made of steel plates, in which 36 grooves are made for the windings. The 3 windings laid in them form a three-phase voltage.
Brush knot. Transmits excitation current to slip rings. It consists of two brushes made of graphite, which press the springs, and a brush holder. On generators of new samples, the brush assembly and the voltage regulator are mounted in a single non-separable housing.
Rectifier. Converts the alternating voltage generated by the generator into D.C. onboard network. Structurally, it is made on heat sink plates with mounted power diodes.
Voltage regulator. It maintains the generator voltage within the specified limits, stabilizes it at different engine speeds, and also changes the battery charging voltage based on the air temperature (the lower the temperature, the higher the voltage).
Generator drive. It is made in the form of a pulley, connected to the crankshaft by a V-belt or V-ribbed belt and rotates 2-3 times faster than the engine crankshaft.

How to choose the right generator

When choosing a generator for a car, in addition to the full compatibility of the device with the original model in terms of dimensions, power, mounting method and other parameters, the product must have a durable housing that is resistant to mechanical stress and provides good cooling of the device, as well as good protection from radio interference.

It is recommended not to buy products that are significantly cheaper than the cost of the original in order to avoid purchasing a low-quality assembly. It is desirable that a suitable alternator model be recommended for installation by the manufacturer of a particular car model.

Installation and replacement of the generator

If it is necessary to replace or repair the generator, it is dismantled in the following order:

Disconnecting the negative battery terminal.
Removing the alternator drive belt from the pulley.
Unscrewing the adjustment bolt and fastening the device to the tension bar.
Disconnecting the wiring harness block from the generator housing.
Disconnecting the wire from the generator output.
Loosening and removing the alternator mounting bolts.
Removing the generator from the engine compartment.

Installation of a new or repaired alternator is carried out in reverse order, after which the correct adjustment of the belt tension is made.

Signs and causes of a malfunctioning generator

Malfunctions of the automobile generator are conventionally divided into electrical and mechanical. Electrical include:

Wear and tear of brushes.
Disruption of contact or breakage of electrical circuits.
Short circuit of the rotor windings.
Damage to the voltage regulator or diode bridge.

Mechanical failures are usually caused by worn bearings, which cause radial runout of the rotor, which will hit the stator winding and cause a short circuit. A malfunctioning generator can be judged by the following signs:

While the engine is running, the low battery light is on or flashing.
Recharging the battery or discharging it regularly.
Dim operation of headlights and electrical appliances while the engine is running.
The intensity of the headlights changes depending on the engine speed.
Extraneous sounds are heard from the generator during its operation.

Diagnostics of generator malfunctions is carried out by checking the removed product on a special stand or by measuring the voltage at the battery terminals with the engine running and not running. If, when the engine is running, the tester shows a voltage of 13.8-14.7 V (depending on the model of the machine), then everything is in order with the generator. A voltage below 12V indicates a breakdown.

Other indications, which also do not correspond to the rating according to the technical documentation, indicate existing problems, in particular, the possible failure of the voltage regulator. In case of mechanical damage, the product is disassembled and worn parts are replaced. If the rotor windings are damaged, they are replaced by rewinding with new ones. If it is impossible to carry out repairs or its cost is comparable to the price of the finished product, a complete replacement is made.

Partial do-it-yourself repair

Some breakdowns of the generator can be repaired on their own. In case of a blown fuse, a failed regulator relay or loose contacts, the repair consists in replacing non-working parts and cleaning the contacts. If a breakdown occurs inside the case, it will need to be disassembled. Generators of different brands of cars are disassembled differently, but the general algorithm is the same, and consists of actions carried out in the following order:

Cleaning the housing from dust and blowing it with compressed air.
Removing the brushes and brush holder held by one screw. At the same time, their condition is checked: if the brushes protrude by less than 5 mm, they must be replaced with new ones. They also clean the mounting sockets, which during operation become clogged with coal dust mixed with oil.
If you need to completely disassemble the device, you need to dismantle the pulley. To do this, use a special grip, made in the form of two half-rings, after having twisted the pulley nut. This work requires certain experience and skill.
Detaching the drive side rear cover and slip rings. The stator, rectifier housing and rotor are also removed.
Disconnecting the wires from the rectifier unit, after which it is removed, and the stator.

In the absence of experience in repairing generators or similar products, do-it-yourself repairs are possible only for minor faults, such as replacing the voltage relay unit, brushes, simple soldering or stripping contacts. Replacement of windings, bearings, repair of the control unit or diode bridge is carried out in a workshop with special equipment by a qualified specialist.

Automotive Alternator Manufacturers

Generators of both our own production and third-party manufacturers are installed on foreign and domestic cars. Replacing a product with a similar one, but from another manufacturer, is possible with a compatible mount, power, similar parameters of the generated current, dimensions and belt drive pulley. Most often, generators of the following companies are installed on cars:

Bosch. It is installed on most European car brands. Differs in simplicity of the device and reliability.
Cargo. Danish company specializing in the production of starters and alternators. Supplies products to many car manufacturers, the price of products is slightly cheaper than the original.
Delco Remy. An American manufacturer that has been on the automotive aftermarket for over a hundred years. The products are of impeccable quality and durability, having all the necessary international certificates.
Lucas. A major British manufacturer of original quality car parts.
Magneton. Czech manufacturer specializing in the production of starters and automotive alternators alternating current. Production is characterized by an optimum ratio of the price and quality.
Valeo. French concern, formed as a result of the merger of several companies producing generators and other components for cars. Products are structurally and operationally similar to Bosch.

Video: Generator device

It's no secret that the generator unit is one of the key components of the vehicle. Therefore, often malfunctions of generators require the immediate intervention of a motorist, since repairs can be expensive if the diagnosis is not timely. Read more about the most common malfunctions and how to solve problems in this article.

Popular faults

If the car cannot start, and you hear the engine compartment buzzing and howling, or the car periodically stalling under load or without it, this may indicate a breakdown of the generator. Removing and disassembling your buzzing generator is the last thing, first you need to understand the main malfunctions and causes. There can be two types of breakdowns that require repair of generators - these are mechanical and electrical types.

The main mechanical damages include breakage of fasteners, device housing, problems in the operation of bearing devices, clamping springs, belt drive. In principle, the causes of a malfunction of a mechanical type generator are very different, but one way or another, they are not related to the electrical part. As for electrical breakdowns, these include malfunctions of the windings, diode bridge, failure of brushes, short circuits, breakdowns, problems in the operation of the relay, etc.

As practice shows, quite often the symptoms indicating the failure of the generating device may appear as a result of other problems. For example, if there is poor contact in the fuse connector, you might think that the problem is with the device. But the same symptom can appear as a result of burnt contacts in the ignition switch. In addition, if the device failure lamp is constantly on, this does not mean that there are problems with the generator, since this may indicate a relay failure.

What are the symptoms of a generator failure?

The low battery light started flashing while the engine was running. It can also burn continuously.
Do-it-yourself generator repair can be carried out when the battery boils away.
When the optics are working, dimmer lighting is noticed. Also, when the engine is running, a bounce may appear. In turn, when the driver presses the gas pedal, that is, the engine speed increases, the brightness of the optics increases significantly. As a rule, this manifests itself during regassing, however, the optics, which began to work brighter, no longer work more brightly.
Generator hums. If the generator howls or buzzes, this first of all indicates its malfunction, which must be solved as soon as possible.
Repair of automobile generators should also be carried out if the car periodically stalls. If the generator howls, while the car stalls right on the go, this may indicate a lack of voltage. Of course, when the car stalls while driving, the driver will first check the battery, but if the battery is charged, it is necessary to diagnose the generator unit (GU).

In what cases is it necessary to replace the generator or repair and service it?

It will be necessary to disassemble the generator in case of such malfunctions:

Mechanical damage or wear of the pulley. If the damage is quite significant, then the alternator pulley is replaced.
Disassembly of the manufacturer's generator in case of wear or damage to the collector brushes.
Breakage of slip rings of the generator (collector wear). Usually the replacement of slip rings is done by hand without problems.
Failure or problems in the operation of the regulator.
Removal of the generator and its repair should also be carried out when the turns of the stator winding are closed.
Maintenance of generators should be carried out in case of complete destruction or wear of bearing parts.
Malfunctions will also lead to its disassembly and repair. The main signs of a diode bridge failure are a weak spark on the candles, as well as a reduced battery voltage.
Various damage to the cables of the charging network.

Troubleshooting and Troubleshooting

What to do if the generator does not start? If the generator whistles? Disassembly and assembly of the generator - in principle, the procedure is not very difficult if you know what to do.

So, how to repair the generator, knowing the main reasons:

Too little battery charge or its complete absence may be the result of the fuse element being burned out or simply moving away due to mechanical shaking. In addition, the lack of voltage in the on-board network may be due to brush wear. In this case, the electrician is very important, since diodes can burn out during power surges, and an open or short circuit can occur in the rotor or stator winding.
To check the performance of the brushes, a visual inspection is usually sufficient. But if there is a break in the wiring or a short circuit in the network, a multimeter may be required for diagnostics. If you do not know how to remove the generator, use the service manual, since the restoration of a broken diode is carried out only by replacing it or soldering it. If it is also necessary to rewind the generator, it will be problematic to implement it at home. To do this, it is better to turn to professionals so that you can be sure that everything will be done correctly. As a rule, the rewinding procedure usually costs less, but if its cost is too high, it may make sense to replace it with a new HU.
As for the repair of the rotor, it can be done on its own. As a rule, the need to repair the rotor is due to a break in the electrical circuit next to the slip rings or unsoldering the ends of the windings. In this case, the repair procedure should begin with the fact that it is necessary to carefully unwind one type of cable. The broken end must be unsoldered, after which, using a soldering iron and consumables, you need to install the finished cable using an unwound coil.
As practice shows, usually it is not even necessary to reduce the number of turns, since the pins are being wired.
To ensure the normal operation of the GU, you can also clean the ring with fine-grained sandpaper. If there are larger damages on the ring, they can be removed using flat files. How to remove the case - again, you need to refer to the service manual, since the dismantling procedure in each case will be different. In the same way, the generator is disassembled or assembled. In the process, you must be careful not to confuse anything. Replacing the slip rings of the generator, as a rule, is carried out in case of their complete damage.
If the GU is very buzzing, most likely the reason is the wear of the rotor bearings. If you notice that the condition of the bearings is rather sad, it may be time to replace them. But it may not be so sad. For example, if the play on the bearings is not particularly critical and is practically not felt, you can simply dismantle the parts and wash them on your own. Before installing the elements, it will be necessary to lubricate the bearings.
The lack of voltage or power surges in the on-board network can usually be solved by changing the regulator relay. It should be noted that the primary cause in this case may be problems in the operation of the diode bridge or some of its components. Diagnostics of the device using a multimeter will allow you to determine the failed diodes.
In the event that the diode icon on the control panel of the instrument informs the driver about problems with the battery voltage, this may indicate a possible breakdown. In particular, we are talking about one of the diodes in the circuit. If you need to get to this circuit with diode components, you will need to unscrew a few nuts from the winding, then remove the nut that secures the positive terminal. When you do this, you will have access to a circuit that can either be replaced or repaired (the author of the video on self-repairing the GU is Vyacheslav Lyakhov).

Conclusion

As practice shows, if you are engaged in self-repair his " iron horse”, then, in principle, you can get rid of most malfunctions on your own. It is important to approach the repair procedure wisely so as not to make it worse, this recommendation is especially relevant for novice motorists. It should also be noted that some repair processes may not be economically effective, for example, we are talking about replacing the stator winding. In this case, it would be most advisable to replace the GU completely. If you doubt your abilities, it is better to entrust the repair procedure to specialists.