Commutation phenomena in electrical machines. Part 3: Experiments using the commutator of a production machine

In earlier parts of the paper, it was established with laboratory turntable rigs that a major mechanism of `flashover¿ involved the generation of a series of intersegmental arcs, and the indluence of various parameters on their generation and behaviour was studied. In the present work, similar experiments have been carried out on the cylindrical commutator of aproduction machine. It has been found that under specific conditions, which are described in some detail, an extensive snd direct arc through the air can be produced between brush arms. The relevance of the work to machine design is indicated.