These were low voltage high current machines. I'm not sure of all the things they were used for, but some powered arc furnaces to refine metals.
The pole pieces for the model were made from 1/2" steel plate machined to shape. Above you see some of the forming taking place on a rotary table mounted on the milling machine.
The commutator was built by turning a copper sleeve and epoxy gluing it on a turned Micarta insulator sleeve , and then sawing a slit between the segments.
Several castings were needed, but I only had to make a pattern for the base. The other patterns were pulled out of my pattern pool.
If you note the brushes are set up like the original, so they can be rotated around to find the place of greatest efficiency. The field magnetism is provided by a stack of ceramic magnets clamped between the pole pieces. The armature is wound with regular magnet wire.
The generator was under construction during most of the month of October, and was finally completed yesterday. Below is a short video of it doing it's thing.