Yes, belt driven from main motor, price is USD.
https://www.ebay.com/itm/CATERPILLAR-C-E-NIEHOFF-28V-570-AMP-ALTERNATOR-GENERATOR-76761-N3240/123020419404?epid=2266377430&hash=item1ca496a14c:g:tlkAAOSwCHZaqRVS
In Germany or Austria, there is plenty of 7-12 ton EURO2, 3 and 4 trucks available...