The generator is driven by a V-belt from the engine crankshaft.
The generator is a three-phase synchronous electric machine with electromagnetic excitation. To convert alternating current into direct current, a diode rectifier is built into the generator. Voltage regulation is carried out by a built-in microelectronic 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, its magnetic poles periodically change under each stator tooth, as a result of which the magnetic flux passing through the teeth continuously changes in magnitude and voltage. This variable magnetic flux creates an electromotive force (EMF) in the stator winding. The wedge-shaped rotor pole pieces are selected in such a way that it allows obtaining a nearly sinusoidal EMF curve.
At high rotor speed, when its generator output voltage begins to exceed 13.6-14.6 V, the voltage regulator is locked and the current does not pass through the excitation winding. When the voltage decreases, the regulator is unlocked again, providing freedom of current flow through the excitation winding. The higher the rotor speed, the longer the regulator remains locked and, accordingly, the more the voltage at the generator output decreases. The process of locking and unlocking the regulator occurs with a high frequency, so the output oscillations remain almost unnoticeable and the generator voltage can be considered constant, maintained at a level of 13.6-14.6 V.
The charging system does not require periodic maintenance, however, the drive belt, battery and its wiring must be checked/replaced on a regular basis in accordance with the Maintenance Schedule (see Chapter Schedule of current maintenance).
When the ignition is switched on, the charge indicator lamp on the instrument cluster should be briefly activated (see Chapter Controls and safe operating techniques). If the lamp does not turn off shortly after starting the engine or is activated during operation of the latter, it is necessary to check the condition of the components of the charging system. Failure to activate the lamp when the ignition is turned on indicates its failure, damage to the corresponding electrical wiring, or malfunction of the generator (including drive belt breakage).
Safety precautions when servicing a generator
- Never disconnect the battery or voltage regulator while the engine is running;
- Never short the generator excitation terminal or the cable attached to it to ground;
- Do not confuse the order of connecting the voltage regulator wiring;
- Remember that turning on a voltage regulator shorted to ground will cause it to fail immediately;
- Never remove the alternator while the battery is connected;
- Do not confuse the polarity of the battery connection;
- Never use voltage meters/test lamps connected to household power (110/220 V) when testing on-board electrical equipment;
- When checking the condition of the diodes, do not apply a voltage higher than 12 V to them and do not use mega-ohmmeters that also have a high output voltage - a breakdown of the diodes will lead to a short circuit. Remember that when checking the insulation of the wiring with a mega-ohmmeter, it is necessary to disconnect all the wiring from the generator;
- When charging the battery without removing it from the car, make sure that both wires are disconnected from it. Do not confuse the polarity of the charger connection;
- Before carrying out any electric welding work on the vehicle, do not forget to disconnect the electrical wiring from the generator and battery;
- Any checks of the circuits and components of the on-board electrical wiring should be carried out with the engine not running and the battery disconnected;
- Remember that reversing the polarity of any connections carries the risk of irreversible failure of the rectifier and generator voltage regulator.