Enamel insulated aluminum foil conductor

Insulated aluminum foil has proved itself superior to round and rectangular copper wire for conductors in electrical coils such as are used in distribution transformers because of its desirable electrical and thermal characteristics as well as decided economic advantages. This paper traces the development of an enamel insulating process for aluminum foil from the initial R&D laboratory work, through the pilot stages and into the beginnings of a high-speed production line. The coating process is described in detail with particular attention to the problem of insulating the edges of the foil. Quality control tests are listed.