I have for long wanted a generator test bed so adjusting the 3rd brush could be done under controlled circumstances after various level of rebuild or repair.
Today I picked up this:
Yes, as is it is for 12 and 24 Volts, but I expect that it can relatively easy be changed to also support 6V. At the end of the day there is a nice rig with a 220V motor and "something" I can mount the T generator in.
It can't be used for Model T's because it's not black!
Good luck and let us know if you get it set up for 6 volts