Try measuring the field coil resistance with an ohmmeter, from the "F" terminal to the insulated brush holder. Use your known 12V field coils as a reference. If there's a noticeably lower resistance, you've got a 6 volt field coil set. I don't know of a quick way to identify a 6 volt armature.
Jerry
Edit: With no wires connected and the armature turning, a polarized generator will produce about 2 volts at the armature terminal, but there's no way to predict where the voltage will go with the field grounded and the armature terminal open-circuited. It would have to be connected to a battery so it can generate some current. Open-circuit voltage can go above 50 volts, and it just keeps increasing as speed goes up.
Last edited by Hotrod Lincoln; 02/19/2010 5:47 PM.
