What RPM should be used when resting a generator by turning it with a lathe?
This should help:
Is that generator RPM or engine RPM? On a T, the generator turns at 1.5 times the engine speed.
I think that is generator speed.
The chart above, thought interesting if you understand how a third brush regulation generator actually works, has little to do with initially setting up a rebuilt Model T generator.
A tool for that purpose spins the generator armature at 1725 RPM which equates to about 28 MPH and is adequate to set the proper charging rate for today's normal driving conditions.
That should be about 5-6 Amps and will keep the battery charges unless you drive a lot at night using the headlamps.
Hop this helps.
I work on Model T generators most days and if you have further questions give me a call.