Automotive generator stator: description, principle of operation and diagram

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

No modern car can "live" without electrical equipment. And the main component of all electrical equipment is the most important source - the generator. In turn, it contains an equally important component that contributes to the generation of electricity while the car is moving. This is a generator stator.

What is it for, what is its purpose and what malfunctions can there be? We will talk about this and something else in this article.

Vehicle electrical equipment

All electrical equipment of any car is represented by the following components:

• Power sources:
• battery;
• generator.
• Power consumers:
• basic;
• long;
• short-term.

The task of the battery is to provide consumers with current while the engine is “resting”, during its start or operation at low speeds. While the generator, in fact, is the main supplier of electricity. It not only powers all consumers, but also charges the battery.

Its capacity, combined with the power of the generator, must meet the needs of all consumers, regardless of the engine operating mode. In other words, the energy balance must be constantly maintained. This is important to know, as it will help you understand how the generator stator works.

The main consumers include the fuel system, including injection, ignition, control, automatic transmission. Some cars have electric power steering. That is, everything that constantly uses current, from starting the engine to completely stopping it.

Long-term consumers are systems that are not used very often. And this is lighting, security (passive, active), heating and air conditioning devices. Most vehicles are equipped with anti-theft systems, multimedia equipment and navigation.

As for short-term consumers, these are the cigarette lighter, starting system, glow plugs, signal, as well as comfort systems.

Design features

The generator is present in every car and consists of the following components:

• stator;
• rotor;
• brush knot;
• rectifier unit.

Both the generator stator and everything else is assembled into a relatively compact module that is installed in close proximity to the engine and is powered by the rotation of the crankshaft, which uses a belt drive.

Functional purpose

The stator is a fixed element of the entirestructure and fixed on the generator housing. In turn, there is a working winding in it, and during the operation of the generator, it is in it that electricity awakens. However, this current is variable, and all consumers need a direct voltage. The transformation (rectification, so to speak) occurs precisely thanks to the rectifier unit.

Among the main tasks of the stator is the carrying function to hold the working winding. It also ensures the correct distribution of magnetic field lines. During the operation of the generator, the working winding can become very hot. And here another equally important function comes into play - the removal of excess heat from the winding.

As a rule, all modern cars use the same type of stator design.

Stator device

The design of the generator stator is formed by the following components:

• ring core;
• working winding;
• insulated winding.

Let's take a closer look at these components.

Core. These are ring plates, on the inside of which there are grooves for the location of the winding. The connection of the plates is very tight, and together they form a so-called package. The rigidity of the monolithic structure is given by welding or riveting.

For the manufacture of plates, special grades of iron or ferroalloys are used, which are distinguished by the presence of a certain magnetic permeability. Their thickness ranges from 0.8 to 1 mm. For better heat dissipationribs are provided, which are located on the outside of the stator.

Winding. As a rule, cars use a three-phase generator, where there are three windings, one for each phase. For their manufacture, copper wire is used, which is covered with an insulating material. Its diameter is 0.9-2 mm, and it fits in the grooves of the core in a special way.

Each of the stator windings of the VAZ generator (or any other brand) has a current removal terminal. As a rule, the number of these conclusions does not exceed 3 or 4. However, there are stators that have 6 conclusions. Moreover, each winding has its own number of pins for a certain type of connection.

Insulation. Insulation is placed in each groove of the core in order to protect the wire from damage. In some cases, special insulating wedges can be placed in the grooves for more reliable fixation of the winding.

The stator is impregnated with epoxy resins or varnishes. This is done in order to ensure the integrity and strength of the entire monolithic structure, which eliminates the shift of the winding turns. The electrical insulation performance is also improved.

How does a stator work?

The principle of operation of the stator, and therefore the entire unit (generator), of any modern car is based on one phenomenon that is familiar to each of us from the time of physics lessons. They often mentioned such concepts as generator, rotor, stator. We are talking about electromagnetic induction. Its essence isnext: when any conductor moves in the area of the magnetic field, then a current is born in it.

Or this conductor (stator) can be in an alternating magnetic field (rotor). This principle is used in automotive generators. During engine start, the generator rotor starts to rotate. At the same time, the voltage from the battery reaches the working winding. And since the rotor is a multi-pole steel core, when voltage is applied to the winding, it becomes an electromagnet.

As a result of the rotation of the rotor, an alternating magnetic field is created, the lines of force of which cross the stator. And here comes the core of the "conductor". It begins to distribute the magnetic field in a special way, and its lines of force cross the turns of the working winding. And due to electromagnetic induction, a current arises, which is removed by the stator terminals. Next, the resulting alternating voltage enters the rectifier unit.

One has only to increase the number of revolutions of the crankshaft, the current is partially supplied from the generator stator winding to the rotor winding. Thus, the generator goes into self-excitation mode, and it no longer needs a third-party voltage source.

Main stator failures

As a rule, the main stator failures are:

1. "Open" of the working winding.
2. Presence of a short circuit.

A characteristic sign by which one can judge the incorrect operation of the stator is the loss of the charging current. This may be indicated by an unlit battery discharge indicator.after starting the engine. In this case, the voltmeter needle will be closer to the red zone.

When measuring the battery voltage when the engine is running, the voltage will be less than the required value. For the battery itself, this is at least 13.6 V, and for the generator - 37.3701 V. Sometimes, in the event of a short circuit on the windings, you can hear the characteristic howl emitted by the generator.

During vehicle operation, the alternator may become hot and subject to electrical loads. In addition, he has to work in the negative conditions of external factors. Over time, this inevitably leads to a deterioration in the state of the insulation of the windings, due to which electrical breakdowns occur. Then you can solve the problem by repair (rewinding the generator stator) or by replacing it completely.

Checking the he alth of the stator

Some beginners are increasingly concerned about the question of how you can check if all the parts of the generator are in working order. To do this, you will need special small equipment in the form of a multimeter (popularly just a tseshka). You can use an autotester or another device that has an ohmmeter mode. In extreme cases, a 12 V light bulb with wires soldered to it will do.

First of all, it is worth removing the generator from the car and disassembling it. Depending on the brand of the car, there may be difficulties, because on some models of the Lexus brand, the power source is in a hard to reach place. Having reached the stator and removed it, it is necessary to clean it from dirt. Next, you can go to theverification.

Check for open circuit

How to check the generator stator for an open? To begin with, it is worth transferring the measuring device to the ohmmeter mode, after which we bring the probes to the winding terminals. In the absence of a break, the multimeter will show values \u200b\u200bbelow 10 ohms. Otherwise, the readings will tend to infinity. Thus, the current through the winding does not pass, which indicates the presence of a break. So you need to check all the conclusions.

In the case of using a light bulb, we check in the following sequence. To begin with, we connect the negative terminal of the battery with one of the winding terminals with a wire (better insulated). Plus, the batteries are fed to another output through the lamp. Its light will indicate complete order, but if the lamp does not light up, then there will be a break. This should be done with every conclusion.

Short circuit test

Now it's time to check the stator for a short circuit. In the ohmmeter mode, we bring the negative probe to the stator housing, and the positive probe to any of the terminals of the working winding. Normally, the readings should tend to infinity. Repeat the procedure for each of the pins.

With a light bulb, the generator stator check is as follows:

• We connect the battery minus with a wire to the stator housing.
• The positive terminal is fed to any output through the bulb.

A light bulb will indicate a short circuit. If it does not catch fire, then everything is in order.

Small note

The listed malfunctions are typical not only forthe generator stator, the voltage regulator, the diode bridge, and the generator rotor may be in doubt. At the same time, it is worth noting that the poor performance of the stator is much less common than that of the listed components of any generator.

Therefore, before taking up the stator, it is necessary to check the voltage regulator and the diode bridge. And if they turn out to be in perfect order, then the last thing to do is winding.

For reliable operation of all electrical equipment of the car, regular maintenance should be carried out and, if necessary, immediately replace the generator stator. The price in the end will not seem as high as when replacing the entire generator.

As for the cost, the prices for new parts start at 1,500 rubles with three conclusions. Products with six contacts will cost more - 6-7 thousand rubles, although there are cheaper options. However, it all depends on the brand of car.