Removal and installation the generator (BMW 5 Series E12)

Warnings:

• It is prohibited to connect the excitation terminal of the voltage regulator or the connecting wire to ground.
• It is not allowed to swap the wires connected to the voltage regulator.
• Do not disconnect wires from the voltage regulator or battery while the generator is running.
• Never remove the generator from the vehicle without disconnecting the wires from the battery.
• The voltage regulator must not be operated without being connected to the generator ground. This will result in immediate failure of the regulator.
• It is forbidden to check (on a car or on a stand) generator-voltage regulator unit without including the battery in the circuit.

When checking the generator, the battery must be in good condition and fully charged.

If you need to charge the battery in a car using a charger, be sure to disconnect the wires from the "+" and "-" terminals of the battery that connect it to the car's electrical circuits.

When connecting the battery, its "-" terminal must be connected to the car's "ground". Changing the polarity will damage the rectifier diodes and voltage regulator.

Before performing electric welding work on a vehicle, disconnect the battery from the ground and disconnect the wires from the generator.

Disconnect the wires from the battery terminals, unplug the generator multi-pin connector.

Disconnect the red wire from the generator "B+" terminal.

Loosen the generator clamp mounting bolts.

Lift the generator and remove it.

The generator is installed in the reverse order of removal. In this case, adjust the drive belt tension, see the "Engine" section "Cooling system".

Replacing generator brushes (without removing the generator)

Disconnect the generator multi-pin connector.

Remove the brush holder.

Unsolder both brush leads.

Install new brushes and solder their terminals.

Disassembly and assembly of the generator

When disassembling and assembling the generator, follow the exploded view provided. Check:

• condition, degree of wear, brush fit to rings and brush clamping force;
• appearance of the contact rings. Contact rings can only be cleaned with a clean rag soaked in gasoline or trichloroethylene. Clean contact rings only with fine-grained sandpaper. Do not use emery cloth for this purpose;
• condition of the bearings. They do not require maintenance, as they contain long-lasting grease;
• appearance of the rotor and stator. Make sure that their windings have no breaks or signs of burning.

The electrical characteristics of the generator should never be tested in a circuit with a voltage greater than 14 V.

When testing the diode rectifier, the DC voltage should not exceed 12 V.

To clean the generator parts, use white spirit or trichloroethylene, then immediately dry them, especially the windings, with compressed air.

Rectifier diodes are sensitive to temperature. Therefore, when replacing them, solder as quickly as possible using pliers with sponges. Using an electric soldering iron is not recommended (its power should not exceed 300 W), since if its insulation is damaged, a short circuit may occur in the rectifier diodes.