The generator is driven by a V-ribbed belt from the engine crankshaft.
The generator is a three-phase synchronous electric machine with electromagnetic excitation. To convert AC to DC, a diode rectifier is built into the generator. The voltage is regulated by a built-in microelectronic voltage regulator.
When the generator is running, the electric current flowing through the excitation winding creates a magnetic field around the rotor poles. When the rotor rotates, the poles of the rotor alternately pass under the stator coils, the magnetic flux changes in magnitude and direction and creates an electromotive force in the stator winding.
At a high frequency of rotation of the generator rotor, when the generator voltage becomes more than 13.6–14.6 V, the voltage regulator is locked and the current does not pass through the field winding. The generator voltage drops, 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 regulator, therefore, the more the voltage at the generator output decreases. The process of locking and unlocking the regulator occurs at a high frequency, so the voltage fluctuations at the generator output are not noticeable, and it can practically be considered constant, maintained at a level of 13.6–14.6 V.
When checking the generator, as well as when operating the car, a number of simple rules must be observed so as not to disable the generator:
- do not operate the generator with the battery disconnected. When the generator is running with a disconnected battery, the voltage in the car's on-board network increases when any electricity consumers are turned off, which leads to failure of the car's electronic equipment, including the voltage regulator and the rectifier unit of the generator;
- do not check the operation of the generator for «spark» even a short connection «positive» generator output with «weight». In this case, a large current flows through the rectifier unit and the diodes are damaged. You can only check the voltage of the generator with a voltmeter;
- «negative» battery terminal must always be connected to «weight» car, and «positive» with generator output. Wrong (reverse) connecting the battery will cause a sharp increase in the current passing through the generator diodes, and they will fail;
- do not test diodes with voltages greater than 12 V or with a megger, as it has too high a voltage for diodes. In this case, when checking, the diodes will be pierced (a short circuit will occur). When checking the insulation of the electrical wiring with a megger, disconnect all wires from the generator;
- it is necessary to disconnect all wires from the generator and the battery when electric welding of components and body parts;
- check electrical circuits and assemblies and troubleshoot with the engine off and the battery disconnected.
Before removing the alternator, disconnect the battery, having previously found out if you have the radio activation code.
Turn off the ignition and disconnect the wire «masses» from the battery.
After installing the generator, connect the wire «masses» to the battery.
Turn on radio and enter the code into it.
Raise the windows with the power windows up to the stop. Then press all power window switches again for at least 1 second to the closed position to activate the power window control unit.
Set the time on the clock.
Six-cylinder petrol engines
Withdrawal
Release the clips and remove the lower mudguard of the engine compartment.
Disconnect and remove the generator air duct.
Unscrew the nuts and disconnect the wires from the terminals «30/B +» And «D +» generator (pic. 18–12).
Pic. 18–12. Arrangement of conclusions of the generator on six-cylinder petrol engines
Pic. 18–13. Location of the front air ducts
Remove front air ducts (pic. 18–13).
Pic. 18–14. Lock Location (1) shroud and direction of rotation for removing the electric radiator fan
To remove the electric radiator fan, disconnect the electrical connector from the fan, remove the cover retainer, turn the cover in the direction of the arrow (pic. 18–14) and remove the fan.
Loosen the screws and remove the V-ribbed belt cover.
Chalk, marker or paint, mark the direction of rotation of the V-ribbed belt. If the V-ribbed belt rotates in the opposite direction during installation, this will lead to its destruction.
Pic. 18–15. Loosening the poly V-belt tension: 1 and 2 - the installation locations of the pins for fixing the tension mechanism. The arrow shows the direction of rotation of the hex wrench to reduce the tension of the V-ribbed belt.
Using a 10 mm Allen wrench, loosen the tension of the V-ribbed belt by turning the tensioner clockwise until the holes are aligned (pic. 18–15).
Lock the tensioner in this position by inserting a 5mm diameter steel rod into the hole.
Remove the V-ribbed belt from the alternator pulley.
Drain the coolant from the cooling system.
Pic. 18–16. An arrangement of collars of fastening of hoses of system of cooling
Loosen the clamps, disconnect the cooling system hoses and move them to the side (pic. 18–16).
Pic. 18–17. Alternator mounting elements on vehicles with six-cylinder gasoline engines: 1 - nut, 45 Nm; 2 - bolt; 3 - bolt, 22 Nm; 4 - generator
Unscrew the nut of the upper fastening of the generator, holding the bolt from turning (pic. 18–17). Remove the upper alternator mounting bolt.
Unscrew a bolt of the lower fastening of the generator 3 and remove the generator.
Installation
Installation is carried out in the reverse order of removal, taking into account the following.
Check that the V-ribbed belt is correctly positioned on the pulleys.
Tighten the lower alternator mounting bolt to 22 Nm.
Tighten the alternator fastening nut to 45 Nm.
Tighten the nuts securing the wires to the terminal «30/B+» torque 16 Nm, to the conclusion «D+» - torque 4 Nm.
Six-cylinder diesel engines
Withdrawal
Loosen the screws and remove the bottom mudguard of the engine compartment.
Pic. 18–18. Tension of the poly-V-belt of the air conditioning compressor: 1 - bolt for fastening the tension roller of the poly-V-belt; 2 - V-ribbed belt of the air conditioner compressor; 3 - torque wrench
Loosen the bolt securing the tension roller of the V-ribbed belt of the air conditioning compressor and remove the belt from the pulleys (pic. 18–18).
Pic. 18–19. The weakening of the tension of the main V-ribbed belt
Using a socket wrench, turn the main V-ribbed belt tensioner counterclockwise, as a result of which the tension will loosen, fix the tensioner in this position with the pin (pic. 18–19) 4 mm in diameter and remove the belt from the generator.
Before removal, mark the direction of rotation of the V-ribbed belt with chalk, marker or paint. If, during installation, the previously used V-ribbed belt rotates in the opposite direction, this will lead to its destruction. Make sure the V-ribbed belt is correctly positioned on the pulleys.
Unscrew the nuts and disconnect the wires from the terminals «30/B +» And «D +» generator (see fig. 18–12).
Pic. 18–20. Bolt location (1 and 2) alternator mountings on vehicles with six-cylinder diesel engines
Remove the alternator mounting bolts and remove the alternator from the vehicle (pic. 18–20).
Installation
Installation is carried out in the reverse order of removal, taking into account the following.
Check that the V-ribbed belt is correctly positioned on the pulleys.
Tighten the right bolt 1 (see fig. 18–20) mounting the generator with a torque of 22 Nm and the left bolt 2 with a torque of 45 Nm.
Eight-cylinder petrol engines (3.7 and 4.2 liters)
Withdrawal
Loosen the screws and remove the bottom mudguard of the engine compartment.
Disconnect and remove the generator air duct.
Unscrew the nuts and disconnect the wires from the terminals «30/B +» And «D +» generator (see fig. 18–12).
Pic. 18–21. Installation of tool 3204 to loosen the tension of the V-ribbed belt on eight-cylinder gasoline engines
Loosen the poly V-belt using tools 3204 and remove the belt from the alternator (pic. 18–21).
Chalk, marker or paint, mark the direction of rotation of the V-ribbed belt. If the V-ribbed belt rotates in the opposite direction during installation, this will lead to its destruction.
Unscrew the nut of the upper fastening of the generator, holding the bolt from turning (see fig. 18–17). Remove the upper alternator mounting bolt.
Unscrew bolt 3 (see fig. 18–17) lower mounting of the generator and remove the generator.
Installation
Installation is carried out in the reverse order of removal, taking into account the following.
Check that the V-ribbed belt is correctly positioned on the pulleys.
Tighten the lower alternator mounting bolt to 22 Nm.
Tighten the alternator fastening nut to 45 Nm.
Tighten the nuts securing the wires to the terminal «30/B+» moment 16 Nm, and to the conclusion «D+» - torque 4 Nm.
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