The generator is driven by a poly-V belt from the engine crankshaft.
The generator is a three-phase synchronous electric machine with electromagnetic excitation. To convert alternating current to direct current, 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 rotor poles alternately pass under the stator coils, the magnetic flux changes in magnitude and direction and creates an electromotive force in the stator winding.
At high generator rotor speed, when the generator voltage becomes greater than 13.6–14.6 V, the voltage regulator is locked and current does not pass through the excitation winding. The generator voltage drops, the regulator opens and again passes current through the excitation winding. The higher the generator rotor speed, the longer the regulator is in the locked state, and 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 a level of 13.6–14.6 V.
When checking the generator, as well as when operating the vehicle, observe the following safety precautions to avoid damaging the generator:
Do not operate the generator with the battery disconnected. When the generator is running with the battery disconnected, voltage surges occur in the vehicle's electrical system when any electrical consumers are disconnected, leading to failure of the vehicle's electronic equipment, including the voltage regulator and the generator's rectifier unit.
Do not check the generator's operation for a spark, even by briefly connecting the positive terminal of the generator to ground. This will cause significant current to flow through the rectifier unit and damage its diodes. Check the generator voltage only with a voltmeter.
the negative terminal of the battery must always be connected to the vehicle ground, and the positive terminal must be connected to the generator terminal. Incorrect (reverse) connection of the battery will sharply increase the current passing through the generator diodes, and they will fail.
Do not test diodes with voltage greater than 12 V or with a megger, as it has too high a voltage for diodes. In this case, the diodes will be broken during testing (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 generator and battery when electric welding body parts.
Check electrical circuits and components and troubleshoot problems with the engine off and the battery disconnected.