[rotorwrench]

Ford used 3-brush generator cut outs clear up through 1939 and clear up into the 50s on tractors. Just make sure the generator output stud is well insulated from the generator case and that the foot on the cut out input is not touching any grounds. Also make certain that that battery wire going to the front can't short out on the cut out case. The cut out looks to be a later unit than what a model A would normally use but it should still do the job if it works. Electro-mechanical cut out relays can be tested but it takes some equipment to do that. The points on the relay pole can stick together and not open the circuit and they can get burned and no longer let current pass when the points are in closed position. The top cap would have to be removed to check it out but that may take some grinding since they are resistance welded in a couple of little spots on the bottom where it joins the relay frame.