The operation of the voltage regulator consists of continuously automatically changing the excitation current of the generator in such a way that the generator voltage is maintained within specified limits when the rotation speed and load current of the generator change.
To check and replace the voltage regulator with a capacitor and brush holder on a car, you will need: flat- and Phillips-head screwdrivers, a 12 mm wrench (two), a DC voltmeter, and a megohmmeter.
1. Remove the rubber boot and connect the "+" wire of the voltmeter to the "B+" terminal of the generator, and connect the "-" wire to the generator body.
2. Start the engine and turn on the headlights.
3. After 15 minutes of engine operation at medium speed, measure the voltage; it should be within 14.4-15.1 V. If undercharging or overcharging is observed, (voltage is not within specified limits), replace the voltage regulator.
4. The capacitor's serviceability can be checked with a megohmmeter or tester (on a scale of 1-10 MOhm). Connect the tester probes to the capacitor terminals. Before connecting, the device shows infinity. At the moment of connection, the resistance decreases and then becomes infinite again. In this case, the capacitor is OK. The faulty capacitor must be replaced.
5. Disconnect the wire from the negative terminal of the battery.
6. Disconnect the connector with wires from the generator terminals.
7. Unscrew the nut and disconnect the wires from the contact stud.
Note: The work on replacing the voltage regulator is performed on the generator installed on the vehicle. For clarity, the generator has been removed from the vehicle.
8. After pressing the three latches, remove the plastic cover from the generator.
9. Disconnect the connector with the wire from the generator diode bridge terminal...
10. ...holding the nut with one key, unscrew the sleeve from the "B+" terminal bolt with the other...
11. ...and remove the bushing, spring and flat washers.
12. Remove the two screws securing the voltage regulator to the generator...
13. ...and remove the voltage regulator.
14. Check the ease of movement of the brushes in the brush holder and their protrusion. If the brushes protrude from the brush holder by less than 5 mm, replace the voltage regulator with the brush holder.
15. Install the voltage regulator on the vehicle in the reverse order of removal.