Posted by Sherman in Idaho [24.32.202.166] on Sunday, March 17, 2013 at 12:04:11 :
In Reply to: Re: Maybe it depends posted by bill [173.48.74.244] on Sunday, March 17, 2013 at 11:41:32 :
I'm familiar with them. The industrial supply catalogs still list them. They're rather like a slightly gritty eraser (like an ink eraser) on a long stick. I just have never found a motor or generator of any kind where a "dirty" commutator or slip rings was causing any sort of problem. Either it's been arcing and is pitted and needs some serious work way beyond what you can do with an abrasive stick, or the "dark" coating is normal and isn't causing any real problem. In fact, a fresh commutator will tend to wear the brushes faster until it develops that graphite/copper-oxide coating, just like a fresh ring job in an engine will go through some initial wear until the rings seat and the bore develops a polish.