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On 31 Jan 2001, at 14:33, Martinez, Leon wrote: > 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: There are lots of tricks to know about commutators. One is the fact that polishing with the wrong type of abrasive will leave bits of abrasive embedded in the copper because the copper is quite soft. The embedded grit will chew away new brushes in no time at all. As a result of this, automotive machine shops just turn the commutator, and usually don't try to polish. It's really not the mirror finish that you're after, it's the roundness. An out of round commutator will certainly give problems. A good machinist can get an amazing finish with a good sharp High Speed Steel tool (don't use carbide.) Of course you should remove the minimum amount of material possible. The whole armature should be tested on a growler before you start. A black spot on the armature is often a sign of an open or shorted section of the armature. This is something that is usually not repairable, but usually results in the generator not working at all. - ******************************* Jim Adney, jadney@vwtype3.org Madison, Wisconsin, USA ******************************* ------------------------------------------------------------------- Pitch in! Send your pledge of support! mailto:support@vwtype3.org