1. Before starting the test, check:
- installation of a generator;
- battery charge level (battery must be fully charged);
- alternator drive belt tension;
- fusible link;
- absence of extraneous noise from the generator when the engine is running.
2. Turn the ignition key to the "OFF" position.
3. Disconnect the cable from the negative terminal of the battery.
Fig. 9.3. Voltage regulator test diagram: 1 – battery; 2 – ignition switch; 3 – red wire; 4 – blue wire; 5 – voltmeter; 6 – generator; 7 – ammeter; 8 – connection point of the tester with the standard wire
4. Connect a digital voltmeter between the generator "S" terminal and ground (connect the "+" terminal of the voltmeter to the generator "S" terminal, and then connect the "–" terminal of the voltmeter to ground or the negative terminal of the battery) (Fig. 9.3).
5. Disconnect the standard wire from the generator terminal "B".
6. Connect a DC ammeter with a measurement range of 0-100 A between the "B" terminal of the generator and the disconnected standard wire (connect the "+" terminal of the ammeter to the "B" terminal of the generator, and the "–" terminal of the ammeter terminal to the disconnected standard wire).
7. Connect the tachometer.
8. Reconnect the cable to the negative battery terminal.
9. Turn the ignition key to the "ON" position and check that the voltmeter reading is equal to the battery voltage.
Attention! If the voltmeter shows 0 V, then there is probably a break in the circuit between the generator terminal "S" and the positive terminal of the battery.
10. Turn off all lights and additional electrical equipment in the vehicle.
11. Start the engine.
12. Increase the engine speed to 2500 min⁻¹.
13. Read the voltmeter readings when the generator output current is less than 10 A.
If the voltmeter readings correspond to the nominal values of the regulated voltage, the voltage regulator is working properly.
If the voltmeter readings do not correspond to the range of nominal values, either the voltage regulator or the generator is faulty.
14. After completing the check, let the engine idle.
15. Turn off the ignition.
16. Disconnect the cable from the negative terminal of the battery.
17. Disconnect the voltmeter, ammeter and tachometer.
18. Connect the standard wire to the "B" terminal of the generator.
19. Connect the cable to the negative terminal of the battery.