- condition, degree of wear, fit of brushes to rings and spring pressure;
- 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.
Note: To check the electrical characteristics of the generator, use devices that do not cause voltage in the circuit to exceed 14 V. Otherwise, some elements of the generator may fail.
Rectifier diodes are sensitive to temperature. Therefore, when replacing them, solder as soon as possible using pliers with sponges. It is not recommended to use an electric soldering iron, since if its insulation is damaged, a short circuit may occur in the rectifier diodes.
It is recommended to clean the generator parts with white spirit; after cleaning, immediately dry the parts, especially the windings, with compressed air.