I guess I'm stuck with trying to use the DC alternators
Just to put you out of your misery.
They is no such thing as a DC alternator.
You have AC alternators and DC generators.
You can get DC from an AC Alternator by putting the output through a rectifier to get DC.
And the other way round you can take the output of a DC generator and put it through a inverter to get AC.
Electric generator - Wikipedia, the free encyclopedia