How to check the anchor of a power tool at home. How to check the generator for performance? Self-check and repair of the generator How to check the mass on the generator

The alternator is the main source of current that feeds the electrical appliances of the car. A malfunctioning car alternator entails insufficient charging of the battery, which leads to a drop in voltage, a blackout and a complete stop in the operation of electrical appliances. For this reason, it is necessary to regularly check the health of the generator and immediately respond to malfunctions in its operation.

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Various signs and symptoms can indicate a decrease in performance and failure of the generator. The main ones are the appearance of noise of a different nature coming from the generator, insufficient battery charge or its complete discharge. In cases where the battery is insufficiently charged, the vehicle either cannot be started or the engine may stall after a short period of time. This may also indicate that the battery has served its useful life.

Signs of mechanical damage to the generator

You can find out about the presence of mechanical damage to the generator by the nature of the sounds it makes during operation. It can be squeaks, whistles, rattling, howling, knocking. More often the problem in this case is wear or insufficient lubrication of the bearings. If, after changing the lubricant, suspicious noises do not disappear, it may be necessary to complete replacement bearings.

The presence of extraneous noise can also be a consequence of the interturn short circuit of the stator winding. In a similar way, a malfunction of connections and contacts is manifested, a short circuit of the winding on the case. All this indicates a malfunction of the interaction of parts during the operation of the generator. You can identify them by visual inspection of the mechanisms. It is easy to detect unwanted winding short circuits, bad contacts and connections. Depending on the degree of identified faults, you can decide whether to fix them yourself or seek help from specialists.

Car alternator voltage diagnostics

The reasons malfunctioning generator may consist not only in mechanical damage to its parts. To detect them, you should also check the indicators of its output voltage. For this purpose, it is necessary to use electrical measuring instruments. Sometimes ohmmeters or multifunction testers - multimeters are used for this.

However, most often it is enough to use a voltmeter. It must be connected to the terminals of the various poles of the battery and the car engine started.

The voltage at the battery terminals when starting the engine should not be less than 8 volts. At the same time, the accuracy of measurements will be higher if they are carried out at an ambient temperature of +20 C and an already warm car engine.
After fixing the indicators when starting the engine, you should gradually increase its speed to 3000 per minute. When such a load is reached, the readings of the voltmeter must be taken into account again. Fixing measurements of less than 12.5 volts will indicate a malfunction of the generator and the need for its repair.

A faulty generator must be dismantled by first disconnecting it from battery terminals. Then you should unscrew the voltage regulator fasteners with a screwdriver. After that, carefully inspect and determine the degree of wear of the generator brushes, as well as its slip rings, and clean them if carbon deposits are present. Often the reason for the loss of performance of the generator is a malfunction of the voltage regulator. Therefore, it must be periodically checked and changed in case of problems.

After troubleshooting, a serviceable generator is mounted in the reverse order of its dismantling. The final action of this process must be the careful connection of the mass.

After installing the generator, you should re-check the voltage readings at the poles of the battery. When the engine is running at 3000 rpm, they should vary from 13.5 to 14.5 volts. These values ​​mean that the generator has been restored and is working properly.

Checking the voltage regulator

The next stage of diagnostics will be a voltage stabilization check. To do this, turn on the high-beam headlights and use a voltmeter to measure the voltage at the battery poles. The deviation of values, not exceeding 0.4 volts from the previous measurements when starting the engine, indicates the health of the generator. Deviations upwards indicate the unstable operation of the generator, the search for the causes of its malfunction will have to be continued.

Checking the car's power circuits

A further search for the reasons for the loss of generator performance is to diagnose the vehicle's power supply circuits. For this purpose, you will also need a measuring electrical device. With it, you first need to check the diode bridge. In this case, the voltmeter is connected to the generator and ground terminals. Instrument values ​​greater than 0.5 volts indicate a diode failure. To determine their breakdown, you should connect a measuring device between terminal "30" and the disconnected connecting wire of the generator. In this case, an electric current strength of less than 5 mA is acceptable.

Then the voltage regulator is checked. In this case, the engine should be warmed up for about a quarter of an hour at medium speed. In this case, all vehicle lights must be turned on. The field of this is measured on the mass and output "30". The optimal performance of the device in this case may differ depending on the type and brand of the car, which can be found in its technical characteristics.

Also, the indicators of the regulated voltage depend on the modification of the car and its parameters, which can be measured by connecting the tester to the battery. Such a measurement is made at maximum engine speed with all the electrical appliances of the car turned on.

The serviceability of the excitation winding is checked by measuring its resistance. To do this, you can use a multimeter or ohmmeter. At the beginning of such an operation, the voltage regulator and brush holder are removed. The winding and its integrity are visually inspected, if necessary, slip rings are cleaned. The meter is connected to the rings. The optimal resistance of serviceable parts should be from 5 to 10 ohms.

A multimeter is needed when diagnosing a short to ground. To do this, we put the tester in the "ringing" mode, touch the armature body with one probe, and the contact ring with the second. It's simple: it doesn't ring - it's working, it rings - it's faulty.

Conclusion

Guided by these recommendations, it is quite possible to diagnose a car generator yourself. To do this, you only need certain skills in mastering the simplest tools for dismantling and mounting, as well as the use of electrical measuring instruments. However, for a more accurate check and thorough diagnosis, you should contact certified car services, whose qualified specialists with the help of special equipment quickly identify and eliminate all problems in the operation of the generator.

Video: how to check the generator

As the saying goes, "No one is indispensable." But in the case of a car, you can make an exception. Have Vehicle such a detail, which is the most important part and truly irreplaceable, is a generator, which is a kind of small power plant. This is the main source of electrical power. If any malfunctions occur in it, this will cause poor battery charging or even the absence of one. Therefore, every motorist must be sure that the generator in his "favorite" is functioning properly. So that such confidence does not leave you, it is necessary to periodically diagnose this element. In this article, we will tell you how to correctly diagnose a car generator with your own efforts.

It's no secret that the priority place for checking a car generator is a specialized car service. But this does not mean at all that it is unrealistic to conduct a correct diagnosis of the unit in the conditions of your own garage, using your knowledge, skills and strengths.

Before you start diagnosing a car generator, you need to purchase a special device that measures voltage. And we are talking, of course, about the multimeter. There are many places where you can find recommendations obliging car owners to stock up on a tester, avometer, voltmeter and ammeter, but we declare with confidence that all these devices are almost identical, and minor differences are only in the set of additional functionality. Choose what is more familiar and convenient for you, each of the listed devices is suitable for conducting an independent voltage test on a car generator.

While checking the mini power plant of your car each owner is obliged to know and remember what is forbidden to do:

1. Check the level of generator performance by short circuit.

2. Connect terminals such as "30" and "67", which are responsible for the mass (in some cases they are encrypted as "B +" and "D +").

3. Forcibly turn on the generator without consumers connected to it. Disconnecting the battery is strictly prohibited.

4. Welding a car body with wires connected from a battery and a generator.

Yet motorist must not forget that:

Naturally, someone else's help is required. The assistant will not have to do anything super complicated, so you should not get hung up on finding specialist mechanics. This is just the case when you can even ask your other half to help you.

Checking the generator valves should be carried out under voltage not exceeding 12V.

If you need to replace the wiring of the generator, then you need to select only those wires whose cross-sectional and length indicators are similar.

Before diagnosing all the elements of a mini power plant, it is recommended to check all connections and the tension of its belt. If the first part is clear, then we will concretize regarding the belt. The correct tension of the alternator belt can be considered rightfully correct only if, when you press on its middle with a force of 10 kg / s, it bends by a maximum of 15 mm, but no more.

Visual diagnostics of the generator

Sometimes one or the other possible problems with a generator can be determined thanks to the battery charge control indicator. If the indicator lamp does not light up when the ignition is turned on, this phenomenon may be accompanied by:

Faulty battery;

Faulty control lamp;

Violation of the integrity of the wires of the indicator circuit or contacts;

Wear of the generator brushes or poor contact on the brush assembly;

Faulty voltage regulator.

In cases where the indicator is constantly lit, regardless of the operating mode power unit, the following problems may occur:

1. Worn or loose alternator drive belt;

2. Breakdown of diodes in the diode bridge circuit;

3. Short circuit of the stator winding, as well as a possible break;

4. Malfunction or failure of the voltage regulator settings.

How to check the generator with your own hands?

Correctly diagnosing a car generator is a rather complicated task, so a clear sequence of certain actions is necessary here. First of all, you need to check the generator relay, then the diode bridge, then the stator, and finally the rotor. In this situation, it is better not to improvise and not to invent, but to act strictly according to plan.

An overvoltage in the vehicle's on-board network can cause many devices to stop working. A relay-regulator is necessary to maintain the correct potential difference. To check this element for normal operation, you must:

1. Switch the multimeter to voltage measurement mode.

2. Start the car engine.

3. Measure the voltage level at the battery terminals or at the generator terminals. The voltage should fluctuate between 14-14.2 V.

4. Click on . This is what the same assistant we mentioned earlier will have to do. The voltage should move upwards by no more than 0.5 V. If the deviation exceeds the norm, then the relay-regulator is faulty.

This device consists of six diodes combined into plates, one of which is negative, and the second, therefore, is positive. The mass of three diodes is on the cathode, the other three are on the anode. The check is carried out according to the following scheme:

1. Turn the multimeter into ohmmeter mode.

2. Connect one probe to the positive terminal of the device, and connect the other in turn to the following terminals: "F1", "F2", "F3" and "0". That is, the first probe remains connected to the plate with a positive value, and the second probe in turn touches the terminals of the diodes pressed into this plate.

3. Swap the probes and repeat the procedure. In one case, the multimeter should show conductivity, that is, resistance of any kind, and in the other it should not. This test is carried out on the positive plate with diodes.

4. Attach one probe to the negative plate, the other to the diode leads.

5. Repeat the same operations as in the case of the positive plate. And again, conductivity will be in one of the cases. So passed the test of the negative plate.

Please note that the resistance must necessarily exceed the zero value. If this is not the case, then there is a high probability that the diode has broken through. This phenomenon can also be indicated by the fact that there is no resistance in both directions during the connection process. The diode bridge can give out insufficient charge even with one good diode, so it is urgent to replace this element.

This block looks like a hollow metal cylinder with generator windings neatly stacked inside it. Checking this element should take place according to the following plan:

1. Disconnect the starter terminals from the diode bridge.

2. Visually check the condition of the winding. It must not show any damage of any kind.

3. Put your multimeter in resistance test mode.

4. Check the winding for breakdowns: measure the resistance between the stator housing and any winding terminal. This value, oddly enough, belongs to the category "the more the better." The ideal option is the desire for infinity with a multimeter going off scale. The device must give a resistance of at least 50 kOhm. Otherwise, the car generator will soon fail.

This element looks like a metal rod, on which the winding is wound, and rings are attached to its ends, along which the generator brushes slip. To diagnose the rotor, you must follow these instructions:

1. Remove the rotor and inspect the condition of the bearings along with the winding.

2. Attach the multimeter leads to the rings. The device must also be in ohmmeter mode. The values ​​obtained should be in the range of 2.3-5.1 ohms.

if the resistance is not measured at all, then somewhere in the winding there is a break.

If the resistance is higher, then there is a bad contact somewhere or the winding leads are incorrectly soldered to the rings.

If the resistance is less, then there is a possibility of an interturn circuit.

This algorithm for carrying out diagnostic work is suitable for many cars, both modern foreign cars and domestic old-timers. But we repeat once again: the main condition is the voltage of the on-board network, equal to 12 V.

The main source of power in the car is the generator, it is such a "mini-power plant". Incorrect or unstable operation of this node is fraught with bad (battery). A failed generator does not provide charging, therefore, the on-board network of the car will work on a battery that will not last for a long time. As a result, the battery is completely discharged, the engine "stalls" somewhere outside the city, and you have a new "headache" and the need to replace the generator.

In order to prevent such a scenario, it is necessary to regularly monitor the status of this device, as well as the charging it gives. If you notice any interruptions in work, you need to check the generator, and you will now learn how to do this.

But before that, I consider it necessary to talk about precautions and certain rules that must be observed when checking this electrical appliance in order not to damage it.

!!! It is forbidden:

• Check the performance of the generator by short circuit, that is, "to a spark."
• Connect terminal 30 (in some cases B+) to ground or terminal 67 (in some cases D+).
• Allow the generator to work without consumers turned on, it is especially undesirable to work with the battery disconnected.
• Carry out welding work on the car body with the wires of the generator and battery connected.

• !!! Important:
• Checking is done with a voltmeter or ammeter.
• Checking the valves is carried out with a voltage not higher than 12 V.
• In the case of replacing the wiring of the electric generator, it is necessary to select wires of the same cross section and length.
• Before checking the device, make sure that all connections are working and that the tension is correct. drive belt. A belt is considered correctly tensioned, which, when pressed on the middle with a force of 10 kg / s, bends by no more than 10-15 mm.

How to check the generator with a multimeter or voltmeter?

Checking the voltage regulator

1. In order to check the voltage regulator, you will need a voltmeter with a scale from 0 to 15 V. Before starting the test, warm up the engine for 15 minutes at medium speed with the headlights on.
2. Measure the voltage between the terminals of the "mass" of the generator and "30" ("B+"). The voltmeter should show normal voltage for the particular vehicle. For example, for a VAZ 2108, it will correspond to - 13.5–14.6 V. If the voltage is lower or higher, most likely the regulator needs to be replaced.
3. In addition, you can check the regulated voltage by connecting a voltmeter to the terminals. It should be noted that the result of such a measurement will not be accurate if you are sure that the wiring is 100% correct. In this case, the motor should operate at medium speeds close to those with the headlights on and other consumers of electricity. The voltage size must match a certain value for a particular car model.

Checking the diode bridge of the generator

1. Turn on the voltmeter in the AC measurement mode and connect it to the "ground" and terminal "30" ("B+"). The voltage should be no more than 0.5 V, otherwise there is a possibility of diode failure.
2. To check the breakdown to "ground", it is necessary to disconnect the battery, as well as remove the generator wire that goes to the "30" ("B+") terminal.
3. Then connect the device between terminal "30" ("B+") and the disconnected wire of the generator. If the discharge current on the device exceeds -0.5 mA, it can be assumed that there is a breakdown of the diodes or the insulation of the generator diode windings.
4. The recoil current strength is checked using a special probe, which is an addition to the multimeter. It is something like a clamp or tongs, which covers the wires, thus measuring the strength of the current that passes through the wire.

Checking the recoil current

1. To measure the recoil current, you need to cover the wire with the probe, which goes to the terminal "30" ("B+").
2. Then, start the engine and take a measurement, during the measurement, the engine should run at high speeds. Turn on electrical appliances in turn and take measurements for each consumer separately.
3. Then count the readings.
4. The following test must be carried out with all power consumers switched on at the same time. The measurement value should not be lower than the sum of the readings of each of the consumers, when you measured each of them in turn, a discrepancy of 5 A downwards is allowed.

Checking the generator excitation current

1. To check the excitation current of the generator, start the engine and give it high speed.
2. Place the measuring probe around the wire connected to terminal 67 (“D +”), the readings on the device will correspond to the value of the excitation current, on a working generator it will be equal to - 3-7 A.

To check the excitation windings, you will need to remove the brush holder and voltage regulator. It may be necessary to clean the slip rings, also check for breaks in the winding or shorts to ground.

The generator plays a very important role in the car, for the engine it is like a mini power plant that supplies the entire on-board network of the car, including the battery (battery). A malfunction of the generator will lead to the inevitable complete discharge of the battery, after which the engine of your car will simply stop working, as well as the entire on-board network. As a result, you will either have to look for a new source of energy. It is very important to detect a generator malfunction in time in order to prevent the above scenario. In order to diagnose the generator, you need to have certain skills and tools. In this article, I will tell you how to check the generator at home with a multimeter.

To begin with, about precautions and safety rules during the inspection

You need to be extremely careful and understand what you are doing in order not to inadvertently damage the generator or its parts (regulator relay, rectifier bridge diodes).

Forbidden:

1. Check the operability of the generator by checking it "for a spark", that is, by the short circuit method.
2. Connect terminal 30 (sometimes referred to as B+) to terminal 67 (D+) or ground.
3. Allow the generator to operate when consumers are turned off, for example, when it is disconnected from the battery.
4. Check generator valves for voltages above 12 V.

It is possible and necessary:

1. Check generator health using a voltmeter or ammeter.
2. During welding work on the car body, it is necessary to disconnect the wires from the generator and battery.
3. During the replacement of wiring in the generator system, the wires must have the same cross section and length as the "native" wires.
4. Before checking the alternator, make sure that the alternator belt is properly tensioned, and that all connections and terminals are in good condition. The tension of the belt is considered normal, at which pressing the middle of the belt with your thumb, it will bend no more than 10-15 mm.

Do-it-yourself car generator check

To check the voltage regulator, you will need a voltmeter with a scale from 0 to 15 V. Before proceeding with the test, let the motor run at medium speed with the headlights on for about 15 minutes. Check the voltage between the "mass" of the generator and the terminals "30" ("B+"), on the voltmeter you should have a normal voltage for your car (for the owners of the "nine", for example, the voltage is considered normal - 13.5 - 14.6 V ). If the voltage is higher or lower than that set by the manufacturer, the regulator will most likely need to be replaced. It would not be superfluous to also check the regulated voltage, for this, connect a voltmeter directly to the terminals. True, the results of such a check cannot be considered 100% correct, because there is a possibility of problems with the wiring. If you are confident that the wiring is correct, then the results can be trusted. The motor must operate at high speeds, which are close to maximum, the headlights and other consumers of the car's electricity must be turned on. The voltage size must match the parameters of your car.

Diode bridge

Checking the diode bridge refers to a set of checks on the generator. In order to check the diode bridge, connect a voltmeter or multimeter to the “30” (“B+”) terminal of the generator, as well as to the “ground”, and turn on the device in the AC measurement mode. Alternating current on the diode bridge should not exceed 0.5 V, if you have more - most likely the diodes are faulty.

Actual:

Breakdowns to "mass"

Checking penetration for “mass” will not be superfluous if “the gene composts brains”. To do this, disable battery and the generator wire that goes to terminal "30" ("B+"). After that, connect the device between terminal "30" ("B +") and the disconnected wire of the generator. We look at the readings - if the discharge current on the device exceeds 0.5 mA, most likely there is a breakdown of the diodes or the insulation of the generator windings.

Recoil current

The recoil current of the generator is checked using a special probe ("lotion" addition to the multimeter in the form of a clamp or tongs), with which the wire is covered, thereby measuring the strength of the current flowing through the wire.

1. To check the recoil current, you need to clasp the wire that goes to the “30” (“B+” terminal) with a probe.
2. Start - during the measurement, it should work at high speeds.
3. Turn on the electrical consumers in turn and read the readings of the device separately for each consumer.
4. At the end of the measurements, you need to calculate the sum of the readings. Next, turn on all consumers (which you turned on one by one) at the same time and measure the multimeter readings. The value should not be less than the sum of the readings of separately measured indicators, the allowable discrepancy is 5 A.
5. Generator excitation current is checked by starting the engine and then running it at high speed. After that, the measuring probe is placed around the wire leading to terminal 67 (“D+”). Serviceable generator should show the magnitude of the excitation current - equal to 3-7 A.

Winding check

To check the excitation windings, you will need to remove the voltage regulator, as well as the brush holder. If necessary, clean the slip rings and check the winding for breaks and shorts to ground. It is necessary to check with an ohmmeter, its probes are applied to the slip rings, after which readings are taken. The resistance should be between 5 and 10 ohms. Then connect one electrode of the device to any of the slip rings, and the other to the generator stator. The display should show an infinitely high resistance, otherwise, the excitation winding closes to ground somewhere.

How to check the generator at home video:

Do-it-yourself generator check and repair video:

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