Preventative replacement of alternator?

[josiahg52]

I'm telling you it's not. I've seen it many times in much, much, much larger generators. Increased brush wear or slip ring grooving in between monthly or biannual maintenance periods always attributed to a change in operating conditions or contamination. Flexibrasing or a quick stoning would bring it back where we'd want it and we'd replace the brushes. On DC generators it was more apparent but commutator action is MUCH more aggressive and much more affected by high temperature and contamination. The polarity swap was done on every 36.months on the multi-gigawatt AC generator and 72 months on a moderately sized few hundred-KW AC generator. The larger generator is expected to be in service for 40 years, the smaller one runs continuously and is generally overhauled every eight or nine years. Again, even on these larger generators with much larger current, we'd expect millimeters over their service lives. An alternator's life is too short, and it's just too small for this action to noticeably affect ring wear. Operating conditions have much more of an affect. There's nothing wrong with swapping the polarities, though.