The generator is driven by a 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 operating, the electric current flowing through the excitation winding creates a magnetic flux around the rotor poles. When the rotor rotates, the south and north poles of the rotor pass under each stator tooth, and the working magnetic flux passing through the stator teeth changes in magnitude and voltage. This alternating magnetic flux creates an electromotive force in the stator winding. The wedge-shaped form of the rotor pole pieces is selected in such a way that it allows obtaining a curve shape of the electromotive force close to sinusoidal.
At high generator rotor speed, when the generator voltage becomes greater than 13.6 - 14.6 V, the voltage regulator is locked and the 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 lock time, and therefore the more the generator output voltage 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.
(Original posted on the website: www.opelbook.ru)
When checking the generator, as well as when operating the vehicle, it is necessary to follow a number of simple rules in order not to damage the generator:
- Do not operate the generator with the battery disconnected from the generator terminal. Without a battery, dangerous surges of voltage occur in the vehicle's electrical system when any electrical consumers are disconnected. These surge voltages can damage the vehicle's electronic equipment, including the voltage regulator and the generator's rectifier block diodes;
- Do not check the generator's performance for a spark, even by briefly connecting the positive terminal of the generator to ground. In this case, a significant current flows through the diodes, and they are damaged. The generator voltage can only be controlled 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 immediately cause increased current to flow through the generator diodes, and they will fail;
- It is necessary to disconnect all wires from the generator and from the battery when electric welding any body parts;
- It is necessary to check the circuits and components of electrical equipment and troubleshoot any faults with the engine not running and the battery disconnected.
Safety precautions when working with a generator
- When working with a generator, first disconnect the battery.
- Before removing the wires from the generator, it is necessary to mark them so that they can be reinstalled strictly in their proper places.
- Do not disconnect the battery or generator while the engine is running.
- When performing electric welding work, disconnect the battery and generator.
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