1. Before the test, check the following:
- Check the fastening of the generator and the reliability of wiring;
- Check the tension of the alternator drive belt;
- Check the fuse box;
- check the noise emitted by the generator when the engine is running.
2. Turn off the ignition.
3. Disconnect the negative battery terminal.
4. Disconnect the terminals "B" of the generator. Connect the DC ammeter to measure the limit of 0-100 A in series between the terminal "B" and disconnected from the alternator wire. Make sure that the negative probe of the ammeter connected to the generator disconnected from the wire.
We recommend using an inductive ammeter, which measures the current flowing through the wire without disconnecting the cable. The use of such an ammeter reduce the possibility of a voltage drop caused by inaccurate connection to the terminal "B".
5. Connect a voltmeter between terminal "B" of the generator and the positive (+) terminal of the battery. Make sure that the positive probe of the voltmeter connected to the terminal "B" of the generator.
6. Connect the cable to the negative terminal of the battery.
7. Connect a tachometer.
8. Leave the hood open.
9. Start the engine
10. Increase the engine speed to 2500 min-1, turn on the headlights and other lights to increase the current produced by the generator, a little more than 30 A. Slowly reduce the engine speed of the engine until the ammeter indicates a current of 30 A. Read the value of the voltage on the voltmeter.
The maximum voltage of the voltage drop: 0.3 V
If the current produced by the generator is high and does not decrease until 30 A, set the current to 40 A, and read the voltage value on the voltmeter.
The maximum voltage drop in this case is 0.4 V
11. If the voltage drop shown by the voltmeter exceeds the desired value, then the wire (including fuse) is damaged or is not securely connected to the terminals of the generator and the battery. Check the connection wires to the terminals and make sure that the insulation of the wire is melted by overheating.
12. Finally, turn the engine in idle mode.
13. Turn off all electric power consumers and stop the engine.
14. Remove the tachometer.
15. Disconnect the negative battery terminal.
16. Disconnect the ammeter and voltmeter.
17. Connect a wire to the terminal "B" of the generator.
18. Connect the cable to the negative terminal of the battery.