Generator failure. Generator circuit

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

Let's figure out why you need and how to repair a car generator. Malfunctions in the device occur for many reasons. In addition, if this happened on the way, then a breakdown of this kind causes a lot of trouble. The fact is that the entire load goes to the battery, therefore, it discharges quickly enough.

Generator circuit and operating principle

If you don't go into too much detail, the device works quite simply. Due to the copper winding on the rotor, a rotating magnetic field is created. At the same time, there is a pulley on the rotor shaft, as well as a fan impeller. When the key is turned in the ignition lock, current flows to the copper winding located on the rotor, as a result of which a magnetic field is formed on the winding. Therefore, the rotor is driven along with the engine crankshaft. When a certain speed is reached, the winding is powered not from the battery, but directly from the generator, that is, it switches from the excitation mode to self-excitation.

Since we get an alternating voltage, a rectifier unit is installed, which converts it intopermanent. It is worth noting that the generator circuit is quite simple, so anyone can deal with it. During the movement from the generator receives an electric current and the accumulator battery. You can monitor the performance of the generator using a special sensor on the dashboard of the car.

How do you know if the electric generator is faulty?

There are a huge number of ways to find out if the device is working properly or not. The simplest of them is to look at the battery charge level of the running engine. If the arrow tends up (to full charge), then the generator is working, but if it is in the red zone, then this indicates that all the electrical systems of the car are powered directly from the battery, which is not good.

Also, in fact, there may be no malfunction of the generator, this happens in cases where the sensor itself is faulty. The same applies to the lamp on the dashboard, which may fail. A prerequisite for a breakdown can be an increased noise level, a whistle during the operation of a running engine, and much more. In most cases, the lack of care for this unit is to blame.

Since the device is located in front of the engine, getting to it is quite easy. Therefore, it should not be difficult to periodically lubricate the friction surfaces, tighten / loosen the belt on the pulleys, and also replace it if necessary.

Alternator self-diagnosis

If you don't want to go tocar service, then the device can be checked independently. As an example, let's take the so-called "classic" VAZ-2107 with a typical generator. The first step is to start the engine, and then observe the headlights. If it is stable for several minutes, then there are no malfunctions of the VAZ-2107 generator. If it is dull, then most likely the cause is a loose pulley nut or insufficient or excessive belt tension. If you apply a force to the belt equal to 10 kilograms / forces (kgf), then the total deflection should be no more than 10-15 millimeters.

If the value obtained was more or less, then you need to tighten or, accordingly, loosen the tension. Also, a malfunction can be determined by an incomprehensible noise in the engine compartment. This happens due to the fact that the vibration loosens the pulley nut, as a result of which it starts to work more noisily and less productively. And now in more detail about the main malfunctions.

Control devices not working

As noted at the very beginning of the article, when the key is turned in the ignition switch, the generator control lamp should light up. If this does not happen, then you need to look for the problem. You should not immediately climb under the hood and dismantle the device, because often this is not a malfunction of the generator, and the problem can be solved much easier. It is necessary to check the fuse in the mounting block under the 19th number, if it is blown, then replace it, and the control devices will work.

Another problem is an open circuit, due towhich may not be supplied with voltage from the ignition switch to the mounting block or from the block to the instrument panel. All this is easily removed. The first step is to check the wire "0", and then "TP". One is responsible for supplying current from the block to the panel, the second from the ignition switch to the block.

Indicator lamp off, low battery

Of course, an indicator is used on the instrument panel, which can simply burn out, and there is no need to look for something more in this. Sometimes just replacing the lamp is enough. There are also malfunctions of the car's generator in the form of insufficient pressing of the lamp cartridge to the printed circuit board, as a result of which malfunctions occur on the dashboard.

As we know, everything fails sooner or later, even with the most careful care. This also applies to the generator. The brushes of the device wear out quite quickly, as a result of which there are problems with operation. In this case, they simply need to be changed. The situation is exactly the same with the oxidation processes of the metal, which no one has canceled yet.

Slip rings oxidize and fail. To fix the problem, you must first change the brush holder, and then carefully wipe the oxidized rings with a rag or napkin, for a greater effect, use gasoline or acetone. Worst of all, if the positive diodes are shorted, because in this case you need to completely change the mounting block.

Generator malfunction: battery discharge, lamp burning unstable

Almost every driver has experiencedown example annoying whistle from under the hood. It's the fault of the alternator belt, which slips due to wear or insufficient tension. If you encounter such a problem, then the usual adjustment or replacement of the belt is enough, its cost is low, about 100-200 rubles.

It cannot be said that the main malfunctions of the generator are damage to the diodes of the rectifier unit and the rotor winding. Both in the first and in the second case, this entails not the best consequences. The problem is eliminated by replacing the rectifier unit or, if possible, diodes.

Stator shorts also happen. In most cases, this damage cannot be repaired, and if restoration work is possible, then buying a new stator is much cheaper and easier. A short circuit to the so-called "ground" may occur, in which case the part needs to be changed.

Increase noise floor, recharge battery

First, let's talk about what makes the generator start to work noisier. The fact is that during operation, bearings work out their resource, which is measured in hours. Therefore, after a certain number of hours they fail. These places begin to work unstable, there is play, knocks, etc. Consequently, the noise level increases.

Of course, it is extremely difficult to foresee such causes of a generator failure, however, you need to be able to understand that the bearing is out of order and it is time to change it. When the so-called "howl" of the generator appears, then thisindicates at least the presence of an interturn circuit in the stator. The loosening of the alternator pulley nut is also fraught with consequences, it must be tightened tightly.

A little more about malfunctions

There are also such malfunctions of the generator as overcharging the battery, this can be tracked by the arrow of the voltmeter on the dashboard. The reason for this may be an exceptionally faulty voltage regulator, which does not cope with its intended purpose. It can be repaired or replaced.

Everywhere has its weak point, this also applies to our case. Such a generator malfunction as wire oxidation is more than common. Fortunately, it is enough to have sandpaper or a metal brush with you, which removes oxide. By the way, the presence of oxidative processes can cause a complete failure of the generator, due to deterioration of the contacts.

Don't forget that bearings need to be lubricated to increase their service life. When axial play appears on the armature shaft, this only indicates that it is time to change the bearing. Do not give preference to unknown manufacturers. It is better to buy a bearing from a well-known company, let it be more expensive, but its resource is much longer. In general, there is a special stand on which you can determine the general condition of the device. It displays the generator circuit, open circuits and much more.

Important points

It cannot be said that periodic he alth checksdevice is the key to trouble-free operation. Of course, no one is immune from a short circuit, but it is possible and even necessary to check the belt tension, the condition of the brushes and rings.

Under no circumstances should you work with the generator with the engine running, as this is dangerous to he alth, because we are dealing with high speeds of the crankshaft and fan. As noted above, the generator circuit is extremely simple, so if necessary, it will not be difficult to study it. This will allow you not only to understand how the device works, but also to carry out most of the repair work yourself.

Conclusion

If we are dealing with "classics", then there are quite often problems with wires. They need to be re-soldered and cleaned. The same applies to the alternator belt, which can break due to intense wear. By the way, its rupture while the car is moving is fraught with the fact that there will be a strong blow. As a rule, the hood gets the most damage, there are cases when, due to a strong blow, paint bounced off the front side of the hood.

It would be useful to carry a spare belt with you. This will eliminate some malfunctions of the VAZ-2107 generator directly on the road. You also need to have the necessary tools with you, that is, flat and Phillips screwdrivers, a set of keys, etc. That, perhaps, is all that can be said about what are the signs of a generator malfunction and how to eliminate them.