When you say it brakes does it come in pieces, or the carbon pick-ups on the part wear out? I roughly translate that part to "modulator" as I am from Greece, but have seen a broken one. The ones I have seen either the diodes on the alternator don't work properly and "burn" the round black thing, the bearings or the carbon parts fail due to age.

Still none of this is relevant if you have fitted a new alternator.

Im afraid I can't be of any help