Start the engine, increase the speed to 3000 rpm -1.
Turn on all consumers: exterior lighting, high beam headlights, heated rear window, heater fan, windshield wiper, hazard warning lights, etc.
Use a voltmeter to measure the voltage at the battery terminals, which should be above 13 V.
If this is not the case, the generator windings, voltage regulator, brush assembly are faulty, or the contact rings of the generator rotor are oxidized.
To make sure that the voltage regulator is working properly, turn off all consumers except the high beam headlights and measure the voltage again.
It should be within 14.4 - 15.1 V. If the voltage is different, the regulator must be replaced.
To check the valves of the generator rectifier block, it is necessary to disconnect the wires from the battery, generator and the “+” terminal of the voltage regulator.
Connect the plus of the battery through a light bulb or probe to the “B+” terminal of the generator, and the minus to its body.
If the lamp is on, there is a short circuit in the valve block.
To check the short circuit in the “positive” valves “+” of the battery, connect through a lamp to the “B+” terminal of the generator, and “—” to the terminal of one of the phase windings of the stator.
If the probe lamp is on, one or more positive valves (diodes) are broken.
To check for open circuit in the stator windings, connect the tester probes (in ohmmeter mode) to the terminals of the stator winding.
If the ohmmeter shows infinity, then there is a break in the winding.
We check the other two windings in the same way.
To check for a short circuit between the stator windings, connect the tester probes between the terminals of the two windings.
The ohmmeter should show infinity, otherwise the windings are short-circuited.
Check the other two windings in the same way.
To check the short circuit in the “negative” valves, connect the “+” valves of the battery through a probe to the output of one of the phase windings of the stator, and connect the “-” valves to the generator housing.
If the probe lamp is on, one or more negative valves are broken or the stator windings are shorted to the generator housing.
To check if the stator winding is shorted to ground, connect the tester probes to the winding terminal and the generator housing.
The ohmmeter must show infinity, otherwise the winding is shorted to ground.
Check the other two windings in the same way.
Inspect the stator windings.
There should be no signs of overheating on the winding insulation, which is a consequence of a short circuit in the valves of the rectifier unit.
If there are signs of overheating on the windings, the stator must be replaced
To check for a break in the rotor winding, connect the tester probes to the slip rings.
If the ohmmeter shows infinity, then there is a break in the winding.
To check the short circuit of the rotor winding to ground, connect the tester probes to the slip ring and to the rotor shaft (or pulley).
The ohmmeter should still set to infinity, otherwise the winding is shorted to ground