On the subject of Leroy Somer furling motors, we learned a bit about them this year--way more than we wanted to.
For the first time since we owned Harmonie, the outhaul motor exhibited classic signs of needing new brushes: irregular operation. When I removed the brush holders, oddly, the brushes looked fine. Upon further disassembly the rest of the story was obvious. 25 years of accumulated carbon dust had obstructed the rotation of the armature to the point that the friction shattered the internal magnets. This motor was dead.
Amel shipped us a new motor which fit and works just fine. Key point here: Whenever changing brushes do not just pull them out of the holder and drop new ones in, but clean out all the dust. Do not let it accumulate inside the motor! Do not assume that previous owners or mechanics did this correctly.
Lesson learned, we completely disassembled the furling motor (which is identical), and cleaned the inside with vacuum and contact cleaner, dressed and polished the commutator, and tested resistances. All checked out well, so they should be good for the next 25 years...
Notes on the new motor: the new Leroy-Somer motor carried the same part number, and was in all key external dimensions identical to the 25 year old original. It mounted and worked just fine. The internals are quite different, however. Key for maintenance is the fact that the brushes are different. Instead of two externally accessible brushes, the new design requires disassembly of the motor and replacement of the entire internal brush holder assembly because the four (not two!) brushes are welded in place to the holder. This emphasizes the importance of sending pictures of parts to Amel when ordering. If you simply order brushes for Leroy-Somer motor Part Number XXX_XXX you might not get what you need.
Other important lessons that would have saved us this cost:
* Electric motors are (almost) forever if regularly cared for. The furling motors hadn't gotten to the top of our list for a professional rebuild.
* Take stuff apart. You learn a lot, and this problem could have been avoided if this motor had been on my "take it apart and put it back together for no reason" list.