Alternator Noise

On Sun, 05 Dec 2004 22:42:57 -0500, Jonathan Goodish
wrote:

My mechanic took a look at the alternator at the last annual inspection
and thought that the cooling fins were backwards (auto style, not
aviation style). Not sure if that's normal for the Cherokees or not,
but I can't believe that Electrosystems would do it wrong.
I also have a Cherokee with a Chrysler alternator. They should be
"aircraft type" as your mechanic puts it. If they are installed
wrong, you will not get good cooling and could have burned something
out prematurely.


How long should I expect this alternator to last? Does this sound like
a rectifier problem that would warrant replacement of the alternator
after just 400 hours? Could it be a regulator problem? Any suggestions?
Alternators life depends on many things, but if your re-build was done
right it should last more than 400 hours. If the fins aren't pushing
air the right way it could warrant another re-build. From just what
you've described, it does not sound like a regulator to me, but I'm no
expert, just someone who got a re-build a couple months ago because of
a whine, and variable voltage output.

If you have a descent rectifier repair shop (alternators, generators,
starters, etc.) in your area, take the alternator to them and have
them bench test it. In about 10 minutes they can tell you anything
and everything that is wrong with it.

HTH and Good luck.
z