Working principle of alternator:
When the external circuit through the brush to energize the field winding, it produces a magnetic field, so that the claw pole is magnetized into N pole and S pole. When the rotor rotates, the flux changes alternately in the stator windings. According to the principle of electromagnetic induction, the three-phase windings of the stator produce alternating induced ELECTROmotive force. This is how an alternator works.
By the prime mover (that is, the engine) drag dc excitation synchronous generator rotor, rotation speed n(RPM), three-phase stator winding resistance induction ac potential. If the stator winding resistance is connected to the electric load, the motor will have AC power output, through the rectifier bridge inside the generator will be converted into DC power output from the output terminal.
The alternator is divided into stator windings and rotor windings. The three-phase stator windings are distributed on the shell according to the electric Angle of 120 degrees difference between each other, and the rotor windings are composed of two polar claws. When the winding of the rotor is connected to direct current, it is excited, and the two pole claws form N pole and S pole. The magnetic field line starts from the N pole, enters the stator core through the air gap and then returns to the adjacent S pole. Once the rotor rotates, the rotor windings will cut the magnetic field lines, in the stator windings of 120 degrees of difference in the electric sine emf, that is, three-phase alternating current, and then through the diode rectifier into direct current output.
When the switch is closed, the battery first provides the current. Circuit is:
Battery positive electrode → charging indicator light → regulator contact → excitation winding resistance → lapping → battery negative electrode. At this point, the charging indicator light will be on because of the current through.
However, after the engine starts, the terminal voltage of the generator increases with the increase of the speed of the generator. When the output voltage of the generator is equal to the voltage of the battery, the potentials of the generator "B" and "D" terminals are equal. At this time, the charging indicator is extinguished because the potential difference between the two ends is zero. Indicates that the generator is working normally and the excitation current is supplied by the generator itself. The three-phase AC electromotive force generated by the three-phase winding resistance in the generator is rectified by the diode, and the output direct current, power supply to the load, and charge the battery.
Product structure of ac generator:
The conversion of high and low speed power supply circuit in work is automatic without any mechanical and electrical control device. Its working principle is analyzed as follows:
The car generator is the main power supply of the car. Its function is to supply power to all electrical equipment (except starter) and charge the battery when the engine is running normally.
Based on the three-phase stator winding of common alternator, a set of three-phase bridge rectifier is added by increasing the winding turns and drawing out the wiring head. At low speed, it is output in series by the original winding and the additional winding, while at high speed, it is output only by the original three-phase winding.
The alternator is generally composed of rotor, stator, rectifier and end cap.
(a) Rotor
The function of the rotor is to generate a rotating magnetic field.
The rotor consists of claw pole, magnetic yoke, magnetic field winding, collector ring and rotor shaft.
The rotor shaft is pressed with two claw poles, each of which has six beak shaped magnetic poles, and a magnetic field winding (rotor coil) and a magnetic yoke are arranged in the claw cavity.
The collector ring consists of two copper rings insulated from each other. The collector ring is pressed on the rotor shaft and insulated from the shaft. The two collector rings are respectively connected to both ends of the magnetic field winding.
When the two collector rings are connected to the direct current (through the brush), a current passes through the field winding and produces an axial flux, so that one claw pole is magnetized as N pole and the other as S pole, thus forming six pairs of alternating magnetic poles. As the rotor rotates, it creates a rotating magnetic field.
The magnetic circuit of the alternator is: magnetic yoke → N-pole → air gap between rotor and stator → stator → air gap between stator and rotor → S-pole → magnetic yoke.
(b) Stator
The function of a stator is to generate alternating current.
The stator consists of stator core and stator winding.
The stator core is made up of silicon steel sheets with grooves in the inner ring, and the conductor of the stator windings is embedded in the groove of the core.
The stator windings are three-phase, and the three-phase windings are star connection or triangle (high power) connection, which can produce three-phase AC.
The three-phase winding must be wound according to certain requirements, in order to make it get the same frequency, equal amplitude, phase difference of 120°three-phase electromotive force.
In domestic JF13 series alternator, the spatial location of six trough a pair of poles (60°electricity per slot Angle), a magnetic pole space position of three slots, so each coil two effective edge location interval is 3 groove, the distance between the adjacent coil beginning each phase winding six slot, the spacing between the beginning of the three-phase winding can be 2 slot, 8 slot, 14 slots and so on.
(c) Rectifier
The function of the rectifier of the alternator is to change the three-phase AC current of the stator winding into direct current. The rectifier of the 6-tube alternator is a three-phase full-wave bridge rectifier circuit composed of six silicon rectifier diodes, which are pressed (or welded) on two plates respectively.
2, Automotive silicon rectifier diode characteristics
(1) Large working current, forward average current 50A, surge current 600A;
(2) High reverse voltage, reverse repeat peak voltage 270V, reverse non-repeat peak voltage 300V;
(3) There is only one lead. And some diode lead is positive, some diode lead is negative, the lead line is a positive tube is called a positive tube, the lead line is a negative tube is called a negative tube, so the rectifier diode has positive diode and negative diode points.
(d) End cover
The end cover is generally divided into two parts (front cover and rear cover), which is used to fix the rotor, stator, rectifier and brush components. The end cover is generally cast with aluminum alloy, which can effectively prevent magnetic leakage and has good heat dissipation performance.
The rear cover is provided with a brush assembly, a brush, brush frame and brush spring. The role of the brush is to direct the power supply through the collector ring to the field winding.
The connection between the magnetic field windings (two brushes) and the generator is different, so that generator can be divided into two types: inner and outer lapping type
Classification of alternators:
Alternator are usually classified in the following three ways:
1. Classification according to the type of electric energy converted
According to the mode of electric energy conversion, it can be divided into ac generator and DC generator.
Alternators are divided into synchronous alternator and asynchronous alternator.Synchronous generator is divided into implicit pole synchronous generator and convex pole synchronous generator. Synchronous alternator are most commonly used in modern power stations. Asynchronous alternator are rarely used.
Ac generator sets can be divided into single-phase generator and three-phase generator. The output voltage of three-phase generator is 380V, and the output voltage of single-phase generator is 220V.
2. Classification by excitation mode
According to the excitation mode, it can be divided into brush excitation generator and brushless excitation generator
The excitation mode of brush-excited generator is other excitation mode, and that of brushless generator is self-excitation mode. The rectifying device of the excitation generator is on the stator of the generator, while the rectifying device of the self-excitation generator is on the rotor of the generator set.
3. Classification by driving power
There are many forms of generator drive power, common power machines are:
(1) Wind turbine
Wind turbine is to rely on the wind driven generator rotation, the generation of current; This kind of generator consumes no extra energy and is a pollution-free generator.
(2) Hydroelectric alternator
Hydraulic generator is a kind of equipment that makes use of green natural resources to generate electricity. It is also called hydrogenerator
(3) Oil-fired generator
Oil-fired alternator rely on diesel or gasoline combustion to generate power to drive the generator set. The use of small oil-fired alternator can play an emergency role. In case of power failure, oil-fired alternator can be started to generate electricity to maintain normal work.
Alternator produced by the factory are manufactured in accordance with the advanced equipment of international standards, which are suitable for engineering parts and car hailing production of various brands, such as Bosch, Denso, Mitsubishi, Deco, Nikko, etc.
When the external circuit through the brush to energize the field winding, it produces a magnetic field, so that the claw pole is magnetized into N pole and S pole. When the rotor rotates, the flux changes alternately in the stator windings. According to the principle of electromagnetic induction, the three-phase windings of the stator produce alternating induced ELECTROmotive force. This is how an alternator works.
By the prime mover (that is, the engine) drag dc excitation synchronous generator rotor, rotation speed n(RPM), three-phase stator winding resistance induction ac potential. If the stator winding resistance is connected to the electric load, the motor will have AC power output, through the rectifier bridge inside the generator will be converted into DC power output from the output terminal.
The alternator is divided into stator windings and rotor windings. The three-phase stator windings are distributed on the shell according to the electric Angle of 120 degrees difference between each other, and the rotor windings are composed of two polar claws. When the winding of the rotor is connected to direct current, it is excited, and the two pole claws form N pole and S pole. The magnetic field line starts from the N pole, enters the stator core through the air gap and then returns to the adjacent S pole. Once the rotor rotates, the rotor windings will cut the magnetic field lines, in the stator windings of 120 degrees of difference in the electric sine emf, that is, three-phase alternating current, and then through the diode rectifier into direct current output.
When the switch is closed, the battery first provides the current. Circuit is:
Battery positive electrode → charging indicator light → regulator contact → excitation winding resistance → lapping → battery negative electrode. At this point, the charging indicator light will be on because of the current through.
However, after the engine starts, the terminal voltage of the generator increases with the increase of the speed of the generator. When the output voltage of the generator is equal to the voltage of the battery, the potentials of the generator "B" and "D" terminals are equal. At this time, the charging indicator is extinguished because the potential difference between the two ends is zero. Indicates that the generator is working normally and the excitation current is supplied by the generator itself. The three-phase AC electromotive force generated by the three-phase winding resistance in the generator is rectified by the diode, and the output direct current, power supply to the load, and charge the battery.
Product structure of ac generator:
The conversion of high and low speed power supply circuit in work is automatic without any mechanical and electrical control device. Its working principle is analyzed as follows:
In the low speed range, due to the low speed of the generator, the three-phase windings in series output, improve the output voltage of the generator, so that the low speed charging performance of the generator is greatly improved. In the high speed range, with the increase of the generator speed, the inductive reactance of the connected three-phase winding increases, the internal pressure drop increases, and the armature reaction is strengthened, so that the output voltage drops. At this time, due to the small internal pressure drop of the original three-phase winding A, B and C, the induced current generated is relatively large to ensure the power output at high speed.
Based on the three-phase stator winding of common alternator, a set of three-phase bridge rectifier is added by increasing the winding turns and drawing out the wiring head. At low speed, it is output in series by the original winding and the additional winding, while at high speed, it is output only by the original three-phase winding.
The alternator is generally composed of rotor, stator, rectifier and end cap.
(a) Rotor
The function of the rotor is to generate a rotating magnetic field.
The rotor consists of claw pole, magnetic yoke, magnetic field winding, collector ring and rotor shaft.
The rotor shaft is pressed with two claw poles, each of which has six beak shaped magnetic poles, and a magnetic field winding (rotor coil) and a magnetic yoke are arranged in the claw cavity.
The collector ring consists of two copper rings insulated from each other. The collector ring is pressed on the rotor shaft and insulated from the shaft. The two collector rings are respectively connected to both ends of the magnetic field winding.
When the two collector rings are connected to the direct current (through the brush), a current passes through the field winding and produces an axial flux, so that one claw pole is magnetized as N pole and the other as S pole, thus forming six pairs of alternating magnetic poles. As the rotor rotates, it creates a rotating magnetic field.
The magnetic circuit of the alternator is: magnetic yoke → N-pole → air gap between rotor and stator → stator → air gap between stator and rotor → S-pole → magnetic yoke.
(b) Stator
The function of a stator is to generate alternating current.
The stator consists of stator core and stator winding.
The stator core is made up of silicon steel sheets with grooves in the inner ring, and the conductor of the stator windings is embedded in the groove of the core.
The stator windings are three-phase, and the three-phase windings are star connection or triangle (high power) connection, which can produce three-phase AC.
The three-phase winding must be wound according to certain requirements, in order to make it get the same frequency, equal amplitude, phase difference of 120°three-phase electromotive force.
1. The distance between the two active edges of each coil shall be equal to the space occupied by a magnetic pole.
2. The distance between the first edge of adjacent coils of each phase winding shall be equal to or multiple of the distance occupied by a pair of magnetic poles.
3. The beginning edge of the three-phase winding should be separated from each other by 2π+ 120°electric Angle (a pair of magnetic poles occupy a space of 360° electric Angle)
(c) Rectifier
The function of the rectifier of the alternator is to change the three-phase AC current of the stator winding into direct current. The rectifier of the 6-tube alternator is a three-phase full-wave bridge rectifier circuit composed of six silicon rectifier diodes, which are pressed (or welded) on two plates respectively.
2, Automotive silicon rectifier diode characteristics
(1) Large working current, forward average current 50A, surge current 600A;
(2) High reverse voltage, reverse repeat peak voltage 270V, reverse non-repeat peak voltage 300V;
(3) There is only one lead. And some diode lead is positive, some diode lead is negative, the lead line is a positive tube is called a positive tube, the lead line is a negative tube is called a negative tube, so the rectifier diode has positive diode and negative diode points.
(d) End cover
The end cover is generally divided into two parts (front cover and rear cover), which is used to fix the rotor, stator, rectifier and brush components. The end cover is generally cast with aluminum alloy, which can effectively prevent magnetic leakage and has good heat dissipation performance.
The rear cover is provided with a brush assembly, a brush, brush frame and brush spring. The role of the brush is to direct the power supply through the collector ring to the field winding.
The connection between the magnetic field windings (two brushes) and the generator is different, so that generator can be divided into two types: inner and outer lapping type
1, Inner iron generator: magnetic field winding negative brush directly iron generator (directly connected with the shell).
2, Outside the iron type generator: the magnetic field winding of the two brushes are insulated from the housing of the generator.
The negative pole (negative brush) of the magnetic field winding of the external iron generator is connected with the regulator, and then the iron is added after passing through.
Classification of alternators:
Alternator are usually classified in the following three ways:
1. Classification according to the type of electric energy converted
According to the mode of electric energy conversion, it can be divided into ac generator and DC generator.
Alternators are divided into synchronous alternator and asynchronous alternator.Synchronous generator is divided into implicit pole synchronous generator and convex pole synchronous generator. Synchronous alternator are most commonly used in modern power stations. Asynchronous alternator are rarely used.
Ac generator sets can be divided into single-phase generator and three-phase generator. The output voltage of three-phase generator is 380V, and the output voltage of single-phase generator is 220V.
2. Classification by excitation mode
According to the excitation mode, it can be divided into brush excitation generator and brushless excitation generator
The excitation mode of brush-excited generator is other excitation mode, and that of brushless generator is self-excitation mode. The rectifying device of the excitation generator is on the stator of the generator, while the rectifying device of the self-excitation generator is on the rotor of the generator set.
3. Classification by driving power
There are many forms of generator drive power, common power machines are:
(1) Wind turbine
Wind turbine is to rely on the wind driven generator rotation, the generation of current; This kind of generator consumes no extra energy and is a pollution-free generator.
(2) Hydroelectric alternator
Hydraulic generator is a kind of equipment that makes use of green natural resources to generate electricity. It is also called hydrogenerator
(3) Oil-fired generator
Oil-fired alternator rely on diesel or gasoline combustion to generate power to drive the generator set. The use of small oil-fired alternator can play an emergency role. In case of power failure, oil-fired alternator can be started to generate electricity to maintain normal work.
Alternator produced by the factory are manufactured in accordance with the advanced equipment of international standards, which are suitable for engineering parts and car hailing production of various brands, such as Bosch, Denso, Mitsubishi, Deco, Nikko, etc.
