Fig. 19.3. Connecting the wires to the generator when checking the voltage drop on the wire connecting the battery to the generator
1. Before testing, check the following items:
- generator status;
- alternator drive belt tension;
- burn-through fuse link:
- absence of abnormal noise from the generator when the engine is running.
2. Turn off the ignition.
3. Disconnect the cable from the negative terminal of the battery.
4. Disconnect the wire from the generator output terminal B and connect a DC ammeter with a measuring range of 0-100 A between the B terminal and the disconnected generator output wire. Connect the positive probe of the ammeter to the B terminal and the negative probe to the disconnected output wire.
5. Connect a digital voltmeter to the B terminal of the generator and the positive terminal of the battery, connect the positive probe of the voltmeter to the B terminal and the negative probe to the positive terminal of the battery.
6. Connect the cable to the negative terminal of the battery.
7. Connect a tachometer or MUT-II device
8. Leave the hood open.
9. Start the engine.
10. Increase the engine speed to 2,500 rpm, turn on the headlights and other lights, and adjust the generator load so that the ammeter shows a current value of slightly more than 30 A.
Read the readings on the voltmeter, it should show a voltage of no more than 0.3 V.
Note: If the generator output current is high and the value displayed on the ammeter does not decrease to 30 A, set the current consumption value to 40 A. Read the readings on the voltmeter, it should show a voltage of no more than 0.4 V.
11. If the voltage shown by the voltmeter is higher than the maximum permissible value, the wire is damaged or is not securely connected to the B terminal of the generator and the battery. Check the reliability of the wire connection to the terminals, and also make sure that the wire insulation has not melted due to overheating.
12. Set the engine to idle mode.
13. Turn off all electrical consumers and the engine.
14. Disconnect the tachometer or MUT-II instrument.
15. Disconnect the cable from the negative terminal of the battery.
16. Disconnect the ammeter and voltmeter.
17. Connect the generator output wire to the B terminal of the generator.
18. Connect the cable to the negative terminal of the battery.