Preparing for the test
Before starting the test, perform the checks listed below.
Check that the battery installed in the vehicle is fully charged. Refer to the battery test procedure for «Accumulator battery».
Check alternator drive belt tension.
Turn the ignition key to position «OFF».
Disconnect the wire from (–) battery terminals.
Connect a digital voltmeter between the terminal «S (L)» generator and «weight».
Connect (+) voltmeter lead to terminal «S (L)» generator, then (–) voltmeter wire to a suitable «mass» (to the body) or to (–) battery terminal.
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 disconnected regular wire.
Connect (–) ammeter wire to the disconnected standard wire.
Pic. 7.21. Voltage regulator test circuit
Connect a reference tachometer in accordance with the instrument manufacturer's instructions. Connect wire (–) battery terminals (pic. 7.21).
Verification procedure
Turn the ignition key to position «ON» and check that the voltmeter reading matches the specified voltage value.
If the voltmeter shows 0 V, then either an open circuit has occurred between the output «S (L)» generator and (+) battery terminal, or the fusible link is blown.
Start the engine. Turn off all lights and additional electrical equipment.
Set the engine speed to about 2500 min-1. Read the voltmeter reading when the generator output current is 10 A or less.
Analysis of results
If the voltmeter readings correspond to the nominal values \u200b\u200bof the regulated voltage given in the table, then the voltage regulator is working. If the voltmeter readings do not correspond to the range of nominal values, then either the voltage regulator or the generator is faulty.
After completing the test, gradually reduce the engine speed to idle, then turn the ignition key to the «OFF».
Disconnect the wire from (–) battery terminals.
Disconnect the ammeter, voltmeter and reference tachometer.
Connect the standard wire to the output «IN» generator.
Connect the wire to (–) battery terminal.