Car generator working principle and precautions

Car generator working principle and precautions

The Car generator is the main power source of the car. Its function is to supply power to all the electric equipment (except the starter) while the engine is running normally (idle speed), and charge the battery at the same time.

On the basis of the three-phase stator winding of the common alternator, increase the number of winding turns and lead the terminal, and add a three-phase bridge rectifier. At low speed, the primary winding and the winding are output in series, and at higher speeds, only the original three-phase winding is output.

working principle

How the overall alternator works

When the external circuit energizes the field winding by the brush, a magnetic field is generated to cause the claw pole to be magnetized to the N pole and the S pole. When the rotor rotates, the magnetic flux alternately changes 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 principle of power generation of an alternator.

The synchronous generator rotor, which is driven by the prime mover (ie, the engine), is rotated at a speed of n (rpm), and the three-phase stator winding senses the alternating potential. If the stator winding is connected to the electric load, the motor has AC power output, and the AC power is converted into DC power from the output terminal through the rectifier bridge inside the generator.

The alternator is divided into two parts: a stator winding and a rotor winding. The three-phase stator windings are distributed on the housing at an electrical angle of 120 degrees from each other, and the rotor winding is composed of two pole claws. When the rotor winding is turned on, it is excited, and the two pole claws form an N pole and an S pole. The magnetic lines of force start from the N pole and enter the stator core through the air gap and return to the adjacent S pole. Once the rotor rotates, the rotor winding cuts the magnetic lines of force, producing a sinusoidal electromotive force of 120 degrees of electrical angle difference in the stator windings, that is, three-phase alternating current, and then becomes a direct current output via a rectifying element composed of diodes.

At present, the alternator is widely used in automobiles, and the following points should be noted when using:

1 Frequently clean the scale and dust on the exterior of the generator, keeping it clean and well ventilated.

2 Always check the fastening of the fasteners associated with the generator and tighten the screws in time.

3 The tension of the drive belt should be appropriate. Too loose, easy to slip and cause insufficient power generation; too tight, easy to damage the belt and generator bearings.

4 When installing the battery, do not install the wrong one. Usually, the positive line is installed first, and the iron wire is not installed. Otherwise, the diode is easily burned out.

5 When the integrated circuit regulator is used, the ignition switch should be turned off immediately when the engine is not running.

6 Never use the “scraping” method to test whether electricity is generated.

7 When the generator has a fault and does not generate electricity, it should be eliminated in time, otherwise it will cause more serious faults.Car generator