Generator

[Las32]

How does a generator with only an armature terminal work? (circa 1932)

[Jay Friedman]

I think it works through a cut-out rather than a voltage regulator which was introduced later in the '30s or the '40s. 

[tcom2027]

Yes the the armature lead goes to a cut out and then to the battery.

The generators are three brush or commonly called third brush generators. The adjustable third brush controls the voltage. When the armature starts turning a current is induced which energizes a coil in the cutout relay closing the points. Current then flows to the battery. When the generator stops turning the coil is de energized and the points are separated by a spring, blocking a back current from the battery.