Briefly describe the structure and composition of automobile electric alternator.

Automobile generator is the main part of automobile power supply, which is responsible for supplying power to all parts and charging the battery when the vehicle is running. Automobile generators can be divided into DC generators and AC generators. Because alternator is superior to DC generator in many aspects, DC generator has been eliminated. At present, all cars use alternators. This paper mainly introduces the basic principle and structure of automobile alternator.

First, the basic principle of automobile alternator

Automobile alternator is also based on the principle of electromagnetic induction. When magnetic flux is cut by a conductor moving in a magnetic field, induced electromotive force will be generated in the conductor. If you try to make the magnetic flux cut relative to the conductor, you can generate electromotive force in the conductor. This phenomenon is called "electromagnetic induction". The basic principle of a generator is that the electromotive force generated by electromagnetic induction generates electric energy (voltage and current). Although the movement of a single conductor in a magnetic field can produce electromotive force, it is very small. If two conductors are connected end to end, a secondary electromotive force will be generated, resulting in a double electromotive force. When a conductor in the form of a coil rotates in a magnetic field, it will produce a great electromotive force, thus forming voltage and current. According to this principle, the generator rotates the coil in the magnetic field to generate electric energy, and the generated current is alternating current with changing size and direction.

Because the greater the power generated by the coil, the easier it is for the coil to heat up due to the action of current. Therefore, the coil is installed on the outer layer of the generator, which is beneficial to heat dissipation. Therefore, all AC generator coils (stator core) are in the outer layer, while rotating magnets (rotor core) are in the coils.

Second, the main functions of automobile alternator

1. Power generation

The multi-groove belt is used to transfer the rotation of the engine to the pulley, make the electromagnetic rotor rotate, and generate AC current in the stator coil.

2. correct, correct; Rectification; Rectification; Find the length

Because the electricity generated in the stator coil is alternating current, it cannot be used for DC electrical equipment installed on the vehicle, so the rectifier is used to convert alternating current into direct current.

Regulating voltage

The regulator is used to adjust the voltage of the generator, which can keep the voltage stable even when the speed or load of the generator changes.

Third, the structure of the generator

It is mainly composed of rotor, stator, brush, rectifier, front and rear end covers, fan and pulley.

1. rotor

The function of the rotor is to generate a rotating magnetic field. The rotor consists of claw pole, yoke, magnetic field winding, slip ring and rotor shaft, as shown in the figure.

2. Stator

Stator, also known as armature, is used to generate alternating current and consists of stator core and stator winding.

3. Fan

Installed on the rotating shaft outside the front cover, it cools the generator when working.

4. Rectifier

The function of rectifier is to change the three-phase alternating current generated by stator winding into direct current output; Secondly, it can prevent the battery current from flowing back to the generator. It usually has six silicon diodes connected to form a three-phase bridge full-wave rectifier circuit.

Step 5 brush

Brush is used on commutator or slip ring as sliding contact for introducing and outputting current. It has good electrical conductivity, thermal conductivity and lubricity, and has certain mechanical strength and instinct to reverse sparks.