Friday, May 22, 2015


    In the same book where I found the Bourbouze motor there were other electrical devises, one of them called the Pacinotti Machine. It looked interesting and after a bit of reading about it, I found that it was invented by Antonio Pacinotti, a professor of physics at the college in Pisa, Italy about 1860. The original machine was designed as a dynamo, but Antonio found that it would also operate as a motor. The invention turned out to be quite significant, although Antonio did not realize what he had stumbled onto until several years after he built it. The principals are still in use today.
     The illustration in the book was enlarged to the size that I wanted to build the device, so that I could simply take measurements right off the picture. For your reference the rotor is about 2 1/2" diameter.
    Construction began by making rotor and stator parts out of 1/4" thick steel plate. The stator part needed to be a ring with the two halves separated by nonmagnetic material.  Antonio used brass so I did the same.
    The 16 coils on the rotor were separated with wood wedges, same as the original. If not the first, this was one of the very first devices to use a commutator. I made this one by cementing copper strips to an insulating hub, and then wrapping with thread cemented in place. I would suspect that is pretty close to how the original was made.
    Finally on the 19th of May it was completed, but I simply could not get it to run as a motor. Then this morning at the suggestion of my friend Paul Spencer, I checked the wiring connections, and I had two of the wires connected wrong. Soon as I exchanged them it took off running like a champ. Here is a video. I have no idea what caused it to slow down near the end, perhaps a poor connection to the power source or something?