IMHO alternators are not the best approach to battery charging
. The copper wired stator (armature) has a positive temperature coefficient which means the hotter it gets, the higher the wire dissipation will be causing it to get hotter. Positive feedback.
There is a good chance the armature is toast. Bearings normally last years under normal conditions. When operated in a high temperature environment
, life could be much shorter. So if you have your failed alternator
rebuilt and if the stator-armature needs rewinding I suggest that you learn ahead of time what type of magnet wire is used. Magnet wire is the varnish
like insulated wire used for these applications and it comes in many temperature classes
. The lowest class that you should consider is E which is rated for 120 degrees C.
alternators could easily be improved with water cooling
. This is not an insurmountable task for manufacturers.