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Pic. 28. Generator.
1. Cover of the generator from the side of slip rings; 2. Rectifying unit; 3. Bolt for fastening the rectifier unit and phase leads of the stator winding; 4, 5. Contact rings; 6. Ball bearing of the rotor shaft on the slip ring side; 7. Rotor shaft; 8. Insulating sleeve; 9. Screw for fastening the brush holder; 10. Positive terminal bolt (conclusion "30"); 11. Insulating sleeve of the contact bolt; 12. Plug of the central output of the stator winding; 13. Brush holder; 14. Negative brush; 15. Positive brush; 16. Hairpin for fastening the generator to the tension bar; 17. Impeller pulley; 18. Beak-shaped pole piece of the rotor on the drive side; 19. Generator drive pulley; 20. Pulley fastening nut; 21. Bearing distance ring; 22.Rotor shaft ball bearing drive side; 23. Generator cover on the drive side; 24. Rotor winding frame; 25. Rotor winding; 26. Stator slot insulation; 27. Stator; 28. Stator winding wedge; 29. Stator winding; 30. Beak-shaped pole piece of the rotor from the side of slip rings; 31. Coupling bolt; 32. Buffer sleeve; 33. Sleeve; 34. Negative diode; 35. Insulating plate; 36. Wire of the phase output of the stator winding; 37. Positive diode; 38. Positive diode holder; 39. Insulating sleeve; 40. Negative diode holder.
1. Cover of the generator from the side of slip rings; 2. Rectifying unit; 3. Bolt for fastening the rectifier unit and phase leads of the stator winding; 4, 5. Contact rings; 6. Ball bearing of the rotor shaft on the slip ring side; 7. Rotor shaft; 8. Insulating sleeve; 9. Screw for fastening the brush holder; 10. Positive terminal bolt (conclusion "30"); 11. Insulating sleeve of the contact bolt; 12. Plug of the central output of the stator winding; 13. Brush holder; 14. Negative brush; 15. Positive brush; 16. Hairpin for fastening the generator to the tension bar; 17. Impeller pulley; 18. Beak-shaped pole piece of the rotor on the drive side; 19. Generator drive pulley; 20. Pulley fastening nut; 21. Bearing distance ring; 22.Rotor shaft ball bearing drive side; 23. Generator cover on the drive side; 24. Rotor winding frame; 25. Rotor winding; 26. Stator slot insulation; 27. Stator; 28. Stator winding wedge; 29. Stator winding; 30. Beak-shaped pole piece of the rotor from the side of slip rings; 31. Coupling bolt; 32. Buffer sleeve; 33. Sleeve; 34. Negative diode; 35. Insulating plate; 36. Wire of the phase output of the stator winding; 37. Positive diode; 38. Positive diode holder; 39. Insulating sleeve; 40. Negative diode holder.
The G-221 alternator serves to power consumers of electrical energy and to charge the battery. It is a three-phase synchronous electric machine with electromagnetic excitation of right rotation (drive side). To convert alternating current to direct current, a six-silicon diode rectifier is built into the generator. Maximum generator output current (at 14 V and 5000 rpm) is 42 A.
The generator is mounted on the engine on the right side and is driven by a V-belt from the crankshaft pulley. Through the holes in the ears of covers 1 and 23, the generator is bolted to the engine bracket and with a pin to the tension bar. To prevent the ears of the covers from breaking off when the bolt is tightened, there is a rubber buffer bushing 32 in the hole of the cover 1. Under the action of the tightening force, the clamping steel bushing (in the figure, it is located to the left of the buffer) is displaced, choosing the gap between the lug and the generator mounting bracket, the buffer sleeve 32 is compressed between the steel bushings and the axial tightening force is not transmitted to the lug.
The main parts of the generator are the rotor, stator 27 and covers 1 and 23, cast from aluminum alloy.
The rotor consists of a shaft 7, on the corrugated surface of which a steel bushing and steel beak-shaped poles 18 and 30 are pressed and forming, together with the shaft and bushing, the core of the electromagnet. On the sleeve between the beak-shaped poles in a plastic frame is placed the winding 25 of the rotor, called the excitation winding. The ends of the winding are brought out through holes in pole 30 and soldered to copper contact rings 4 and 5 mounted on a plastic sleeve.
The rotor rotates in two closed type ball bearings 6 and 22. Grease is put into the bearings during their manufacture and does not require replenishment during operation. The inner race of the front bearing 25 is loosely fitted on the rotor shaft and, together with the spacer ring 21, is clamped by the pulley fastening nut between the pulley hub and the shaft collar. The outer race of this bearing is pressed into the cover and fixed between two steel washers tightened with four screws. After tightening the nuts, the ends of the screws are punched to prevent self-unscrewing of the nuts. The inner cage of the rear bearing 6 is pressed onto the rotor shaft, and the outer one enters the seat of the cover 1 and is pressed with a rubber ring.
On the rotor shaft, with the help of a key and a nut, a pulley 19 with an impeller 17 of the fan is fixed, which serves to cool the rectifier and the internal parts of the generator. Air is sucked into the windows of the cover 1, passes between the stator and the rotor, and is thrown out through the windows of the cover 23 by the fan impeller. A spring conical washer is installed between the pulley hub and the nut, with its convex side facing the nut. The pulley and fan are made of sheet steel and connected by electric welding.
The stator core 27 is made of plates of electrical steel with a thickness of 1 mm. In four places on the outer surface of the plate are connected by welding. On the inner surface of the stator there are 36 semi-closed slots, insulated with cardboard. A three-phase stator winding is laid in the grooves, secured against falling out with wedges 28, which are plastic tubes. Each phase winding consists of six coils connected in series. Phase windings are connected in a star with a zero point output to plug 12 (unmarked). This pin is used to connect the battery warning lamp relay. To increase the electrical strength and thermal conductivity of the winding, the stator is impregnated with varnish.
On the cover 1 of the generator, a brush holder 13 with brushes 14 and 15 is fixed with a screw. Through brushes made of a copper-graphite mixture and pressed by springs to the slip rings of the rotor, current is supplied to the excitation winding. Brush 14 is connected through a plate to "weight" generator, and brush 15 - with a plug "67". The rectifier parts are also attached to the cover 1 of the generator. The rectifier converts the alternating current generated by the generator into direct current, which is used by consumers of the car's electrical energy.
The rectifier is assembled according to a three-phase bridge circuit of six silicon diodes of the VA-20 type - semiconductor devices that pass current in only one direction. Diodes are located in a special rectifier block, consisting of two aluminum holders 38 and 40 with diodes. In order to simplify the design of the rectifier, three diodes are on the case "plus" rectified current ("positive" diodes). They are pressed into the holder 38, connected to the output "30" generator. The other three diodes create on the case "minus" rectified current ("negative" diodes). They are pressed into the connected "weight" rectifier unit holder 40 connected to "weight".
The diodes are pressed into aluminum holders in order to ensure efficient heat dissipation from their body to the holders, which are blown through with air for cooling. If the diodes fail, they cannot be replaced individually - the entire rectifier unit must be replaced.
On production generators before 1977, negative diodes were pressed into cover 1, and positive diodes into an aluminum holder connected to the output "30" and attached instead of a rectifier unit to cover 1. With these generators, it was possible to replace individual damaged negative diodes by carefully pressing and pressing them on a press. If the positive diode failed, then it was necessary to replace the entire holder with positive diodes.
The generator works as follows. When the ignition switch is in position 1 (ignition), an electric current passes through the excitation winding of the generator, creating a magnetic flux around the rotor poles. When the rotor rotates under each tooth of the stator, then the south, then the north beak-shaped pole of the rotor passes and the magnetic flux passing through the stator winding changes in magnitude and direction. This variable magnetic flux creates an electromotive force in the stator winding. The beak-shaped shape of the rotor poles is chosen in such a way as to obtain the shape of the electromotive force curve close to sinusoidal.