1. Cover of the generator from the side of slip rings. 2. Bolt for fastening the rectifier unit. 3. Contact rings. 4. Ball bearing of the rotor shaft on the slip ring side. 5. Capacitor 2.2uF±20% to suppress radio interference. 6. Rotor shaft. 7. Common output wire for additional diodes. 8. Clamp «30» generator to connect consumers. 9. Plug «61» generator (common output of additional diodes). 10. Output wire «B» voltage regulator. 11. Brush connected to the outlet «IN» voltage regulator. 12. Voltage regulator. 13. Brush connected to the terminal «W» voltage regulator. 14. Hairpin for fastening the generator to the tensioner. 15. Generator cover on the drive side. 16. Fan impeller with generator drive pulley. 17. Pole tip of the rotor. 18. Bearing mounting washers. 19. Distance ring. 20. Ball bearing of the rotor shaft on the drive side. 21. Steel bushing. 22. Rotor winding (excitation winding). 23. Stator core. 24. Stator winding. 25. Rectifier block. 26. Coupling bolt of the generator. 27. Buffer sleeve. 28. Sleeve. 29. Clamping sleeve. 30. Negative diode. 31. Insulating plate. 32. Phase output of the stator winding. 33. Positive diode. 34. Additional diode. 35. Positive diode holder. 36. Insulating sleeves. 37. Negative diode holder. 38. Cover. 39. Positive conclusion. 40. Barette. 41. Negative conclusion. 42. Cork. 43. Indicator for checking the electrolyte level. 44. Separator. 45. Positive plate. 46. Negative plate. 47. Corps. 48. Battery discharge warning lamp. 49. Fuse box. 50. Ignition relay. 51. Ignition switch. 52. Battery. 53. Generator.
Generator
Technical specifications:
- Maximum recoil current (at 13 V and 5000 rpm), A - 55
- Limits of adjustable (voltage, V — 14.1±0.5
- Direction of rotation (drive side) - Right
- Generator weight, kg - 4.85
On VAZ-1111 vehicles, a three-phase alternating current generator of type 37.3701 is used with a built-in rectifier unit and a microelectronic voltage regulator. It serves to power the consumers of the car with electric current and to charge the battery.
The generator is installed on the left side of the engine (front, when viewed in the direction of the car). With a bolt passing through the paws of covers 1 and 15, the generator is attached to the bracket on the cylinder block, and with a pin 14 - to the tension bar. The cover 1 has a buffer device consisting of steel 28. rubber bushings 27 and clamping bushing 29. When tightening the nut of the generator mounting bolt, the clamping bushing abuts against the end of the rubber bushing, deforms it and presses the bushing 28 to the mounting bracket. As a result, the axial clearance between the paws of the generator covers and the bracket is selected, and the covers are unloaded from the axial tightening force, which can deform or break off the paws of the covers.
The generator is driven from the crankshaft pulley by a V-belt transmission with a gear ratio of 1:2.04. Belt tension is adjusted by turning the alternator relative to the mounting bolt to the bracket. The belt tension should be such that under the action of a force of 10 kgf, the belt bends by 10... 15 mm. With a weak tension, the belt may slip on the pulleys, which leads to a decrease in the generator voltage and recoil current. In addition, the pulley, shaft and bearings of the generator are very hot, the grease in the bearings overheats, and they can fail. Excessive belt tension increases the load on the bearings and causes premature wear.
The main parts of the generator: a rotor, a stator, a cover 1 with a rectifier unit 25, a cover 15 with a bearing 20, a pulley with a fan 16 and a brush holder with a voltage regulator 12. The covers and the stator are pulled together by four tie bolts 26.
The generator rotor is a rotating electromagnet. Steel beak-shaped pole pieces 17 and bushing 21, pressed onto the rotor shaft 6, form the core of the electromagnet. Between the pole pieces in a plastic frame is the winding 22 of the rotor, called the excitation winding. The current is supplied to the winding through copper contact rings 3, to which the winding leads are soldered. The rings are located on a plastic sleeve, also pressed onto the rotor shaft.
The rotor shaft rotates in two ball bearings: 4 and 20, installed in covers 1 and 15. Sealed type bearings. The lubricant incorporated in them during manufacture is sufficient for the entire service life of the generator. The rear bearing 4 is pressed onto the rotor shaft, and its outer race is pressed by a rubber ring placed in the cover groove. The front bearing 20 is pressed into the cover 15 and, for reliability, is clamped between two steel washers 18, tightened with four screws. The ends of the screws are punched. The inner race of this bearing, together with the distance ring 19, is clamped by the pulley fastening nut between the pulley hub and the shaft step.
The generator stator consists of a core 23 with a winding 24. The core is made of plates of electrical steel, connected in four places by electric welding. On the inner surface of the core there are 36 semi-closed grooves, insulated with a fluoroplastic film. The stator winding is laid in the grooves, the ends of which are connected in a star without a zero point output.
Fan 16 is used to cool the rectifier, stator and rotor, which heat up when the generator is running under load. The cooling air enters the windows of the cover 1, passes between the stator and the rotor, and is thrown out through the windows of the cover 15 by the fan impeller. The fan and pulley are made of sheet steel and connected by electric welding.
The rectifier that converts the alternating current of the generator to direct current is made in the form of a rectifier unit 25. It consists of two aluminum plates with six diodes of the VA-20 type pressed into them - semiconductor devices that pass current in only one direction. To simplify the design of the rectifier, diodes of different polarity are used - «positive» and «negative». For positive diodes on the case, a «plus» rectified voltage, and for negative - «minus». Positive diodes are pressed into plate 35 of the rectifier unit, and negative diodes into plate 37.
The rectifier unit is attached to the cover 1 with three bolts 2, insulated together with the positive diode plate 35 from the cover with plastic bushings. The nuts of the bolts 2 simultaneously clamp the leads of the diodes and the stator winding. Clamp connected to plate 35 «30» (8) generator, which is the output «plus» rectifier. Conclusion «minus» is the mass of the generator.
Three additional diodes 34 are also installed on the plate 35 of the rectifier unit. The voltage removed from these diodes is used to power the excitation winding 22 and the generator health monitoring circuit using a battery discharge indicator lamp 48.
The generator voltage is regulated by a microelectronic non-contact voltage regulator 12, fixed with a screw on the cover 1. This is a non-separable and unregulated unit, and it completely lacks any electromagnetic relays with contacts. Closing or opening of the power supply circuit of the excitation winding of the generator occurs due to the opening or closing of a powerful output transistor in the regulator, depending on the magnitude of the control voltage at the output «B» regulator.
A plastic brush holder with two brushes 11 and 13 is inserted into the groove of the voltage regulator, through which the excitation winding of the generator is fed. Brush 11 is connected to the output «IN» voltage regulator, and brush 13 - with an output «W». This output is located on the inside of the regulator and is not marked on its body.
Generator operation
Contacts close when ignition is turned on «15/1» and «30/1» ignition switch, then contacts «30» and «87» ignition relay 50, and a current begins to flow through the excitation winding of the generator, closing along the path: «plus» battery 52 - contacts «30» and «87» ignition relay 50 - fuse 2 fuse blocks - control pump 48 - output «61» generator - output «IN» voltage regulator 12 - excitation winding 22 - output «W», the output transistor of the voltage regulator is ground.
The control lamp of the 48th battery discharge is on, indicating that the excitation winding is powered by the battery.
The current flowing through the excitation winding creates a magnetic flux around the rotor poles. After starting the engine, the generator rotor rotates and under each stator tooth passes either the south or the north pole of the rotor. Therefore, the magnetic flux passing through the stator teeth varies in magnitude and direction. This variable magnetic flux crosses the turns of the stator winding and creates an electromotive force in it.
The alternating voltage and current induced in the stator winding are rectified by the rectifier unit, and the rectified direct current taken from the terminal is used to power the consumers «30» generator. At the same time, a rectified voltage is removed from the common output of additional diodes 34 to power the excitation winding of the generator.
At a working serviceable voltage generator at the clamp «30» and on the common output of additional diodes (plug «61») are equal. Therefore, no current flows through the control pump 48 and it does not burn. In this case, the excitation winding of the generator is powered by a rectifier with three additional diodes, and the battery is charged by the generator.
If the control lamp 48 is on, this indicates a malfunction of the generator, that it does not give voltage or it is lower than the battery voltage. In this case, the voltage at the plug «61» (generator voltage) below clamp voltage «30» (battery voltage). Therefore, a current flows in the circuit between them, passing through the control lamp, and it burns.
With an increase in the rotor speed, the generator voltage increases. When it starts to exceed the level of 13.6...14.6 V, the output transistor in the voltage regulator 12 is turned off and the current through the excitation winding is interrupted. The generator voltage drops, the transistor in the regulator opens and again passes current through the excitation winding.
The higher the frequency of rotation of the generator rotor, the longer the time of the closed state of the transistor in the regulator, therefore, the more the generator voltage decreases. The described process of locking and unlocking the regulator occurs with high frequency. Therefore, voltage fluctuations at the output of the generator are imperceptible, and practically it can be considered constant, maintained at the level of 13.6... 14.6 V.
In 1996, the device of the voltage regulator and brush holder was changed. Now the voltage regulator is placed in a metal case (like a powerful transistor) and riveted to the brush holder, i.e. forms an inseparable knot with it. The new voltage regulator is missing a pin «B», and voltage is applied only to the output «IN». According to their characteristics, the old and new voltage regulators are the same and, assembled with a brush holder, are interchangeable.
Accumulator battery
Rechargeable battery - lead-acid, type 6ST-36A, low-maintenance. It is designed to supply consumers of the car with electric current when the engine is not running, as well as to power the starter when starting the engine. Batteries are made by several factories and therefore may have slight differences in design.
The battery is made up of six batteries connected in series, each of which has an EMF of 2.1 V in a charged state. Thus, the total EMF of the battery is 12.6 V. The nominal capacity of the battery is 36 Ah at a 20-hour discharge mode with a current of 1.8 A.
The accumulators of the battery are placed in a polypropylene translucent case 47, divided by partitions into six compartments. The jumpers connecting the individual batteries to each other pass through the partitions of the compartments and are welded to the bars 40. From above, the batteries are closed with a common polypropylene cover 38, welded to the body by ultrasonic welding. The cover has openings for filling the electrolyte and for the passage of the polar terminals of the battery.
Each battery consists of a block of alternating plates - positive 45 and negative 46. Plates of the same polarity are welded to barets 40, which serve to fasten the plates and output current. The plate gratings are cast from an alloy with a low antimony content. As a result, the processes of electrolyte decomposition and battery self-discharge slowed down. This made it possible to check the level and density of the electrolyte much less often, which is why the batteries began to be called low-maintenance or maintenance-free.
The plates in the blocks are isolated from each other by thin and microporous separators 44, made in the form of envelopes, into which the positive plates are inserted. The small thickness and large porosity make it easier for the electrolyte to penetrate through the separators, which reduces the internal resistance of the battery and allows you to get a large discharge current.
The battery refers to chemical current sources. The electrolyte in it is a solution of sulfuric acid in distilled water. The density of the electrolyte of a fully charged battery at 25°C should be 1.28 g/cm3 year-round for the central and southern regions of the country, and for the northern (with an average January temperature from -50 to -30°С) in winter 1.30 and in summer 1.28 g/cm3.
When the battery is discharged, the sulfuric acid of the electrolyte interacts with the active mass of the plates and turns it into lead sulfate, while the amount of acid in the electrolyte decreases and its density decreases. Therefore, the density of the electrolyte can be used to judge the degree of discharge of the battery. For example, a decrease in density by 0.04 g/cm3 corresponds to a battery discharge of 25%, and 0.08 g/cm3 — by 50%. A battery discharged by more than 50% in summer and 25% in winter must be recharged.
When a battery is charged, the current flowing through it converts lead sulfate into lead peroxide in the positive plates and into spongy lead in the negative plates. In this case, sulfuric acid is released into the electrolyte, and its density increases.
The normal electrolyte level in the batteries should be between the marks «MIN» and «MAX», on the translucent battery case. If there are no marks, then the level should be 5...10 mm above the edge of the separators and not rise above the lower edge of the indicator 43.