Always check the following before testing:
- installation of the generator and connection of wires;
- alternator drive belt tension;
- fusible insert;
- the absence of extraneous noise from the generator when the engine is running.
Turn the ignition key to position «OFF».
Disconnect the wire from (–) battery terminals.
Disconnect the standard wire from the output «IN» generator. Connect ammeter (DC, with a range of 0-100 A) in series between output «IN» generator and its standard wire. (Connect (+) ammeter wire to terminal «IN» generator and then wire (–) ammeter to the wire disconnected from the generator).
Note. We recommend using an ammeter with an inductive type sensor («current clamp»), which allows you to measure the current without disconnecting the wire from the output «B» generator. The use of this device eliminates the possibility of voltage drops due to poor connection to the terminal «B» generator.
Pic. 7.22. Generator output voltage drop test circuit
Connect a digital voltmeter between the terminal «IN» generator and (+) battery terminal. Connect (+) voltmeter lead to terminal «IN» generator and then wire (–) voltmeter to (+) battery terminal (pic. 7.22).
Connect the previously disconnected wire to (–) battery terminal.
Connect a control tachometer or tester.
Start the engine.
While maintaining the engine speed at about 2500 min-1, turn on and off the headlights and outdoor lights, thereby adjusting the load on the generator so that the amount of output current (shown on the ammeter) would be slightly higher than 30 A.
Limit value: 0.3 V maximum.
Note. If the output power of the generator is high and you cannot reduce the ammeter reading to 30 A by turning on the load, then set the generator output current to 40 A. The maximum allowable voltage drop for a 40 A output current is 0.4 V.
If the voltmeter readings exceed the maximum permissible value, then there is probably a malfunction in the output circuit of the terminal «B» generator. In this case, you should check the circuits between the output «IN» generator and (+) battery terminal (including fusible link). If the wire to the alternator terminal is loose, or if the wire insulation in the harness has changed color due to overheating, repair the problem and recheck.
After completing the check, let the engine idle.
Turn off all exterior lights, then turn the ignition key to the «OFF».
Disconnect the control tachometer or tester.
Disconnect the wire from (–) battery terminals.
Disconnect the voltmeter and ammeter.
Connect the standard wire to the output «IN» generator.
Connect the wire to (–) battery terminal.