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 imperceptible, and it can practically be considered constant, maintained at the level of 13.6–14.6 V.
When checking the generator, as well as when operating the vehicle, observe the following safety precautions so as not to damage the generator:
Do not operate the generator with the battery disconnected. When the generator is running with a disconnected battery in the vehicle's on-board network, voltage increases occur when any electricity consumers are turned off, leading to failure of the vehicle's electronic equipment, including the voltage regulator and the generator rectifier unit.
Do not test the generator for «spark», even a short-term connection «positive» generator output with «weight». In this case, a significant current flows through the rectifier unit and its diodes are damaged. Check the generator voltage only with a voltmeter.
«Minus» battery terminal must always be connected to «weight» car, and «positive» connect to the generator output. Wrong (reverse) connecting the battery will dramatically increase 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 an ohmmeter, disconnect all wires from the generator.
Be sure to disconnect all wires from the alternator and battery when electric welding body parts.
Check circuits and components of electrical equipment and troubleshoot with the engine off and the battery disconnected.