Mercury Arc Rectifier Phenomena

Peter Cooper Hewitt invented the mercury arc rectifier in 1902, so that it can hardly be considered a new development. More than a half dozen different manufacturers are producing mercury arc rectifiers of various types and sizes and have been producing such rectifiers for years, so that commercial development is not new, yet technical literature is astonishingly bare of treatments going to the fundamentals of rectifier behavior. Many articles appear, describing this and that installation. Descriptions of structural details are not wanting. For specific glass rectifiers, performance curves are available which give the relation between current and voltage at which failures occur under standard conditions. Even this information does not seem to be published for the iron tank rectifiers. An engineer wishing to familiarize himself with the quantitative relations underlying rectifier design has thus practically nothing to go on. We cannot assume from this that manufacturers the world over have proceeded blindly for nearly a quarter of a century, but if they do know what happens in a mercury arc rectifier they at least have not told the public. The purpose of this paper is to present such information as is at present available to the author. This information does not include the knowledge of very important groups in the industry and would even seem to indicate that a very large aggregate capacity of rectifiers has been designed along incorrect lines.