When the battery charge on the car disappears and the replacement of brushes does not help, it means that the problem is hidden in the generator itself. Troubleshooting should start by checking the diode bridge.
It is necessary
- - A set of keys;
- - screwdrivers;
- - 100W soldering iron;
- - multimeter or ohmmeter.
Instructions
Step 1
Remove the alternator from the machine for troubleshooting. Depending on the make of the machine and the model of the engine, its location may be different, which in some cases greatly complicates the procedure for dismantling the generator. To remove the generator, loosen its hinge bolt, then loosen the belt tension with a wrench, turning the alternator belt tension adjustment bolt in the right direction until you can remove the belt from the pulleys. If you are not going to change the alternator belt, remove the belt only from the alternator pulley if other drive belts interfere with removing it from the drive pulley. Having removed the belt, disconnect the connector with the control wires and unscrew the nut that will pull the power wire to the terminal of the diode bridge of the generator. With the generator free, unscrew the hinge bolt completely and remove the retaining bolt securing the generator housing to the shim. After that, remove the generator from the engine compartment.
Step 2
Disassemble the generator. To do this, use a socket wrench to unscrew the bolts holding the front and rear of the generator, then carefully separate the case. Try to keep the stator on the front wall when disassembling the case, since the stator windings are directly soldered to the diode bridge.
Step 3
Remove the diode bridge from the front of the generator. Use a Phillips screwdriver to unscrew the diode bridge fixing bolts, then use a socket wrench to unscrew the positive terminal fixing nut on the generator. Look carefully, perhaps the negative terminal of the bridge is also attached to the case with a separate nut. If so, unscrew this nut as well. After you have unscrewed all the mounting bolts, remove the front wall of the generator.
Step 4
Unsolder the diode bridge from the generator windings. Preheat a powerful soldering iron, irradiate its tip, after which you can easily unsolder the stator winding leads from the bridge. Unsolder the winding leads, slowly, applying the heated tip of the soldering iron to the soldering point and at the moment the solder melts, using a flat screwdriver, as it were, remove the bridge leads from the winding leads. Unsolder all 4 points, after which the diode bridge will be released and it will be possible to ring it.
Step 5
Using an ohmmeter, check each diode separately, without disassembling the bridge structure, since other diodes, if they are working, do not affect the measurement result. Diodes should show conductivity in one direction only. If you have a digital multimeter, then pay attention to the readings of the device. They should be close. Such a device shows not only the conductivity, but also the voltage drop across the diode junction. The normal voltage drop is 170-250 millivolts and depends on the specific brand of diodes. In the opposite direction, there should be no conductivity.
