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My generator brushes keep burning and burning, I even had to stock a box of brushes, cleaned the contacts, still burning. Yesterday I found the problem. The story: The first time I noticed my brushes were worn was last month near Christmas, I decided to change points because they were no longer touching the contacts on the armature also the generator light would blink or stay on . The armature was blackened so I cleaned it with light sandpaper. Two weeks ago my brushes were worn down again and a spot on the armature was once again blackened. Yesterday I decided to perform some more meticuluos surgery, Took the generator apart, cleaned between the copper contacts from copper powder and carbon from the brushes; sanded the contacts with very fine sandpaper , then polished with rubbing compound until I can see myself and finally cleaned the contacts with electrical contact cleaner spray to remove all my work's residue. I was proud of myself to perform this proceedure as my dad instructed me . He has done this before in the 50's when generators were common and this proceedure made the brushes last many times longer than just changing them. One must make sure their are no deep gouges present and epecially no sharp corners at the edge of every contact; good rubbing with rubbing compound takes care of ths last problem. I was proud of myself until my dad pointed out that there was a flat spot on the armature contacts; this was the spot that would get blackened very quickly. My brushes bobbed up and down and I never noticed it because I was not looking for it. I must now either get it lathed or machined or buy a rebuilt one. I was told that the cause of the flat spot was a short with contamination in the form of brush powder or other stuff shorting two contacts. This in turn would caused sparking which I saw alot.; eventially the copper would burn off showing as a flat spot. This flat spot even when clean will make the brushes float, this floating again would cause the brushes to almost touch the contacts and in turn cause arcing. This arcing would burn away the brushes and some copper. This would leave copper pits and carbon deposits on the contacts which I did have. This is the moral of the story make sure to perform maintenance and inspection to the copper contacts when replacing bushes, It should be absolutly clean on the surface and shiney (polish it, it's like micro polishing), you should be able to see the dark insulation bettween the the contacts. Clean the insulation area with a sharp tool but do not gouge the insulation out. doing so will leave a neat place for conductive contamination to accumulate and short out contacts. Leave no sharp edges between insulators because these may even grind down brushes in one day. Do not forget to polish with tooth paste or rubbing compound to remove and soften all scratches and sharp edges. Last, clean your work with some kind of cleaner. Do not forget to test your contacts for shorts with a resistance meter. I think the proceedure is in the Bently manual, I am not sure . This will make the brushes last long time. LEON MARTINEZ martinezl@ftscpac.navy.mil 1969 SQUAREBACK EFI/AUTO SAN DIEGO AND TIJUANA ------------------------------------------------------------------- Too much? Digest! mailto:type3-d-request@vwtype3.org Subj=subscribe