From my generator repair days...
The larger tractor trailers trucks have alternators with a 24 VDC output and a smaller 12 V output. That could used to run the larger UPS.
The '60 and '70 cadillacs used to use 100+ Amp alternators.
There also was a cheap engine driven welder that was nothing more than a little Briggs engine driving a rewound alternator. Maybe the name was Honeybee?