The automobile generator is the main power source of the automobile, and its function is to supply power to the electrical equipment other than the starter and charge the battery at the same time when the engine is running normally. On the basis of the three-phase stator winding of the ordinary alternator, the number of winding turns is increased and the terminal is led out, and a set of three-phase bridge rectifier is added. At low speed, the original winding and the increasing winding are output in series, and at higher speed, only the original three-phase winding is output.
The car generator is the source of power for the electric equipment on the car after the car is started. So, how does a car generator work?
The principle is very simple, that is, the most basic principle of electromagnetic induction (magnetism generates electricity): a part of the conductor in the closed circuit and the magnetic field cut the magnetic induction line movement, and the induced current is generated in the circuit, and the magnetism generates electricity.
When the vehicle is energized, the current of the battery passes through the brush to energize the field winding, and the field winding (stator) generates a magnetic field. After the vehicle is started, the rotor uses the power of the engine (belt drive) to start rotating at the rated speed to cut the magnetic line of induction. At this time, a corresponding voltage is generated in the stator. At this time, the current generated is alternating current and cannot be used directly. It needs to be converted into direct current through a rectifier inside the generator, supplied to various electrical equipment on the car or converted into chemical energy and stored in the battery.
Generally, automobile generators are composed of rotors, stators, regulators, front and rear covers, fans, pulleys and other components. Its working principle is that when the external circuit energizes the field winding through the electric brush, a magnetic field is generated, so that the claw poles are magnetized into N pole and S pole. Battery positive → charging indicator light → regulator contact → excitation winding → grounding → battery negative.
The rotor is the magnetic field component of the generator, and its role is to generate a magnetic field. It is mainly composed of claw poles, magnetic poles, excitation windings, slip rings, rotor shafts, etc. Two claw poles are mounted on the rotor shaft, and excitation windings are installed in the cavity of the claw poles. The slip ring is composed of two copper rings insulated from each other, press-fitted on the rotor shaft and insulated from the shaft, and the two slip rings are respectively connected to the two ends of the excitation winding. When direct current is applied to the two collector rings, current flows through the field windings, and axial magnetic flux is generated, so that one of the claw poles is magnetized as N pole, and the other is magnetized as S pole, thus forming six pairs or Eight pairs of interlaced magnetic poles.
The role of the stator is to generate alternating current, which is composed of a stator core and a three-phase stator winding, and is fixed between the front and rear covers. The stator core is laminated by ring-shaped silicon steel sheets, which are insulated from each other, and the inner circle has slots, and the slots are embedded with three-phase stator windings. For a rotor with 6 pairs of magnetic poles, each group of windings has 6 coils connected in series to form a three-phase winding, which is symmetrically embedded in the slots of the stator core. There are two types of three-phase winding connections: star and delta. Generally, star connection is adopted. Its role is to generate induced electromotive force. The stator is installed outside the rotor and fixed with the front and rear ends of the generator. When the rotor rotates inside it, it causes a change in the magnetic flux in the stator winding, and an alternating induced electromotive force is generated in the stator winding. The stator is composed of a stator core and a stator winding. The stator core is made of silicon steel sheets with grooves in the inner ring and insulated from each other.
The brush assembly is composed of two brushes, a spring and a brush holder; the brush is installed in the hole of the brush holder. The pressure of the spring keeps the brush and the integrated electric ring on the rotor assembly in close contact. The rotor windings provide field current. The lead wires of the two brushes are respectively butt-connected with the ground terminal of the magnetic field terminal of the rear cover.
Rectifier is a component that converts alternating current into direct current. Generally, a three-phase bridge rectifier circuit is used as a rectifier in a generator. The function of the rectifier is to convert the three-phase alternating current generated by the stator windings into direct current. The rectifier is composed of rectifier diodes. The rectifier of the 6-tube alternator is composed of 6 silicon rectifier diodes which are press-fitted or welded to two mutually insulated plates, one of which is a positive plate with output end bolts. ; The other is the negative plate, which is directly connected to the generator shell (grounding), or the back cover of the generator can be directly used as the negative plate. 6 rectifier diode atmosphere positive tube and negative tube. The lead electrode is the positive electrode is called the positive tube, and the lead electrode is the negative electrode is called the negative tube.
The regulator has electric shock type, transistor type and integrated circuit type according to different structures.
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