You will need: 10 mm wrenches, Phillips and flat-head screwdrivers, ohmmeter (autotester), test lamp
Remove the generator from the car (see "Replacing the Niva Chevrolet generator").
Mark the relative positions of covers 4 and 8 (Fig. 1) of the generator.
Press the three latches.
Remove the plastic casing.
Remove the two screws securing the voltage regulator.
Remove the voltage regulator with the brush holder by disconnecting the wire from the regulator terminal.
Remove the four screws securing the rectifier unit and the screw securing the capacitor.
Bend back the three stator winding terminals so that they allow the rectifier unit to be removed
Remove the rectifier unit with the capacitor
To replace the capacitor, unscrew the nut of the contact bolt, remove the washer and spacer bushing.
Remove the condenser wire tip from the contact bolt.
Unscrew the four clamping screws (the screws are tightened with a large torque).
Spring and flat washers are installed under the screw heads.
Using a screwdriver, remove the generator cover from the slip ring side.
Clamp the generator rotor in a vice (not too tightly, so that the rotor does not turn) and unscrew the pulley mounting nut.
Remove the spring washer and pulley.
Remove the thrust washer.
Remove the rotor from the cover on the drive side.
Remove the spacer ring from the rotor shaft.
Inspect the contact rings.
If they have burrs, marks, scratches, traces of wear from brushes, etc., the rings must be ground.
If the damage to the rings cannot be removed, sandpaper, you can turn the rings on a lathe, removing a minimum layer of metal, and then polish them.
Check the rotor winding resistance with an ohmmeter (tester), connecting it to the slip rings.
If the ohmmeter shows infinity, then there is a break in the windings and the rotor needs to be replaced
Check with a test lamp for a short circuit in the winding to the rotor housing.
To do this, plug the test lamp into a 220 V AC network (you can use a battery and a 12 V lamp).
Connect one wire to the rotor housing, and the second one to each ring in turn.
In both cases, the lamp should not light.
If the lamp lights in at least one case, then
Inspect the stator. There should be no traces of the anchor touching the stator on the inner surface of the stator.
If there is wear, the bearings or generator covers should be replaced.
Check for a break in the stator winding.
To do this, connect the test lamp to the 220 V AC network (you can use a battery and a 12 V lamp).
Alternately connect the test lamp between all the terminals windings.
In all three cases, the lamp should light.
If the lamp does not light, there is a break in the winding.
Replace the stator or winding. There is a short circuit and the rotor must be replaced.
Check if there is a short circuit between the stator windings and the housing.
To do this, connect the test lamp to the 220 V AC network (you can use a battery and a 12 V lamp) B).
Connect the lamp to the stator winding terminal, and the wire from the power source to the stator housing.
If the lamp lights up, there is a short circuit: the stator or winding must be replaced.
Inspect the generator cover from the drive side together with the bearing.
If, when rotating the bearing, you feel play between the rings, rolling or jamming of the rolling elements, the protective rings are damaged or there are signs of grease leakage, and cracks are found in the cover, especially in the places where the generator is attached, you must replace the cover together with the bearing (the bearing is rolled in the cover).
Check the ease of rotation of the bearing from the side of the contact rings.
If, when rotating the bearing, you feel play between the rings, rolling or jamming of the rolling elements, the protective rings are damaged or there are signs of grease leakage, the bearing must be replaced.
To do this, use a puller to press the bearing off the rotor shaft and press on a new one using a suitable mandrel, applying force to the inner ring of the bearing.
Inspect the generator cover from the side of the slip rings.
If cracks are found, the cover must be replaced.
Check the serviceability of the voltage regulator.
Check the serviceability of the capacitor.
Damage to the capacitor or loosening of its fastening on the generator (deterioration of contact with ground) is detected by an increase in interference to radio reception when the engine is running.
The capacitor can be checked with a megohmmeter or tester.
If there is no break in the capacitor, then when the probes of the device are connected to the terminals of the capacitor, the arrow should deviate towards decreasing resistance, and then m gradually return back.
You can check the rectifier unit both with the generator removed and without removing the generator from the car.
The check procedure is the same. For clarity, the test diagrams are shown on a removed generator.
To test on a car, disconnect the wires from the battery and generator, and remove the block with the wire from the voltage regulator terminal.
This is how the diodes of the generator rectifier bridge are located: 1 - positive diodes with a red mark on the housing: 2 - negative diodes with a black mark on the housing: 3 - additional diodes.
Remove the brush holder from the generator.
Check the diodes of the rectifier unit using a 12 V test lamp and a battery.
To check for a short circuit in the positive and negative diodes, connect the "+" of the battery through a test lamp to the "B+" terminal of the generator, and the "-" of the battery to the generator body.
The lamp should not light: if it lights, there is a short circuit.
The unit must be replaced.
To check the positive diodes, connect the "+" of the battery through a test lamp to the "B+" terminal of the generator, and the wire coming from the "-" of the battery to one of the stator winding terminal mounting screws.
The lamp should not light: if it lights, there is a short circuit in the positive diodes.
The unit must be replaced.
To check the negative diodes, connect the "+" of the battery via a test lamp to one of the stator winding terminal mounting screws, and the wire coming from the "-" of the battery to the generator housing.
The lamp should not light; if it lights up, then there is a short circuit in the negative diodes.
The unit needs to be replaced.
To check the additional diodes, connect the "+" of the battery through a test lamp to the contact of the voltage regulator junction block, and the wire coming from the "-" of the battery to one of the stator winding terminal mounting screws.
The lamp should not light; if it lights up, then there is a short circuit in the additional diodes.
The unit must be replaced.
Assemble the generator in the reverse order of removal.
In this case, orient the generator covers in accordance with the previously made marks.
Install the generator pulley spring washer with the convex side facing the nut. Tighten the nut to a torque of 39-62 Nm (3.9-6.2 kgf).