- condition of the brushes, degree of their wear, fit of the brushes to the rings and spring pressure;
- appearance of the contact rings. Contact rings can only be cleaned with a clean rag soaked in gasoline or trichloroethylene. Contact rings can only be cleaned with fine-grained sandpaper. It is prohibited to use emery cloth for these purposes;
- condition of the bearings. They do not require maintenance, as they contain long-lasting grease;
- outer shaft of the rotor and stator. Make sure that their windings have no breaks or signs of burning.
Note: The electrical characteristics of the generator should never be tested in a circuit with a voltage greater than 40 V. Otherwise, some elements of the generator may fail. Test the diodes only in a circuit with a DC voltage of no more than 12 V.
Rectifier diodes are sensitive to high temperatures, so soldering when replacing them should be done as soon as possible, using pliers with sponges. It is recommended to use an electric soldering iron with a power of no more than 300 W for these purposes, since if the soldering iron insulation is damaged, the diodes may be damaged.
To clean the generator parts, use white spirit or trichloroethylene; immediately after cleaning, dry the parts, especially the windings, with compressed air.