What are the structural principles of automobile generators? Graphical analysis

The most fundamental principle of automobile generators is based on the principle of electromagnetic induction. When the external circuit energizes the excitation winding through the brush, a magnetic field is generated, causing the claw pole to be magnetized into the N pole and the S pole. When the rotor rotates, the magnetic flux changes alternately in the stator winding, and according to the principle of electromagnetic induction, an alternating induced electromotive force is generated in the three-phase winding of the stator. This is the power generation principle of automobile AC generators.

The car generator is a key device in the car electrical system. It is responsible for providing power to all electrical devices (except the starter) when the engine is running, and also charging the battery. Its working principle is based on the principle of electromagnetic induction, and the rotating magnetic field of the rotor generates an induced electromotive force in the stator winding.

On the basis of the three-phase stator winding of an ordinary AC generator, the number of winding turns and lead-out connectors are increased, and a set of three-phase bridge rectifiers are added. This design can increase the output current and capacity of the generator to meet the needs of the automotive electrical system.

The structure of an automobile generator usually includes a rotor, a stator, and a rectifier. The rotor consists of a rotor shaft, a rotor core, a rotor winding, a fan, etc. Its function is to generate a rotating magnetic field. The stator is stacked with stator silicon steel sheets. The outer circle of the stator core is punched with several slots to embed the stator winding. The stator winding is a three-phase winding with a phase difference of 120° electrical angle in space. When the generator is running, the three-phase stator winding cuts the magnetic lines to generate three-phase alternating current. The function of the rectifier is to convert the three-phase alternating current of the stator winding into direct current.

The structural principle of automobile generator mainly includes the following aspects:

Rotor: The rotor consists of a rotor shaft, rotor core, rotor winding, fan, etc. The rotor core is generally made of 0.5mm thick silicon steel sheets. The rotor winding is direct current, and a magnetic field is formed after the excitation current is passed. When the generator is running, the rotor will generate a rotating magnetic field.

Stator: The stator is made of stacked silicon steel sheets, and the outer circle of the stator core is punched with several slots to embed the stator winding. The stator winding is a three-phase winding, and the three-phase winding differs by 120° electrical angle in space. When the generator is running, the three-phase stator winding cuts the magnetic lines of force to generate three-phase alternating current.

Rectifier: The function of the rectifier is to convert the three-phase AC power of the stator winding into DC power. The function of the AC generator rectifier is to convert the three-phase AC power of the stator winding into DC power. The rectifier of the 6-tube AC ​​generator is composed of 6 silicon rectifier diodes to form a three-phase full-wave bridge rectifier circuit. The 6 rectifier tubes are pressed (or welded) on two boards.

End cover: The end cover is used to support and protect the stator and rotor, and also serves as a support seat for installing bearings and bearing caps. The end cover is generally divided into two parts (front cover and rear cover), which play the role of fixing the rotor, stator, rectifier and brush assembly. The end cover is generally cast with aluminum alloy, one is to effectively prevent magnetic leakage, and the other is that aluminum alloy has good heat dissipation performance. The rear cover is equipped with a brush assembly, which consists of a brush, a brush holder and a brush spring. The function of the brush is to introduce the power into the magnetic field winding through the collector ring.

When the external circuit energizes the field winding through the brush, a magnetic field is generated, and the claw poles are magnetized into N poles and S poles. When the rotor rotates, the magnetic flux changes alternately in the stator winding. According to the principle of electromagnetic induction, an alternating induced electromotive force is generated in the three-phase winding of the stator. This is the power generation principle of the AC generator.

In addition, automobile generators are also divided into DC generators and AC generators. Among them, AC generators can be divided into synchronous generators and asynchronous generators. Synchronous generators can be divided into ordinary AC generators, integral AC generators, and AC generators with pumps; asynchronous generators are rarely used. In addition, AC generators can also be divided into single-phase generators and three-phase generators. With the continuous development of automobile technology, the performance and efficiency of automobile generators are also constantly improving. In the future, automobile generators will be more efficient, environmentally friendly and intelligent.

The maintenance methods of automobile generator are as follows:

1. Properly adjust the tightness of the generator belt.

2. Pay attention to the degree of bearing wear and replace it in time if there is any problem.

3. Ensure that the rectifier has less scale and can be cleaned regularly.

4. If the brush contact surface is uneven, you can use fine sandpaper to smooth it.

5. If the brush is too short but not damaged, you can use a gasket to insert it into the bracket to make it fit tightly against the rectifier.

6. The brush holder insulator is damaged and needs to be replaced with a new one.

7. If the generator breaks down midway and is not too far from the destination, the wires connecting the magnetic field coil to the voltage regulator can be removed. If it is a three-brush generator, the third brush must be removed so that the generator stops generating electricity and uses battery power. At this time, you should save electricity as much as possible.

8. The dustproof ring on the generator must be firm and should not be removed to prevent dust from entering the interior and causing machine failure.

9. Clean the wires regularly.

10. Remove dirt and dust from the generator surface.