Applications of the hot-cathode grid-controlled rectifier, or thyratron

During the past few years a variety of applications have been found for the hot-cathode grid-controlled rectifier. In the present paper a general review is made of those industrial applications which are known to be economically possible. In order that the paper may be kept to a reasonable length and of general interest, a detailed account of the problems arising and results achieved with each application has not been attempted. A brief description of this rectifier (or thyratron) is given, together with some elementary principles which must be observed when designing circuits suitable for use with it. The grid circuit, especially, gives rise to problems and operating features probably not met with hitherto in industrial control apparatus. Though originally developed as a sensitive relay, the thyratron has now reached such a stage that it is able directly to control power of some magnitude, and thus has uses other than relaying. A Table is given showing the four main groups into which applications may be classified. Examples in each of these groups are dealt with briefly. The paper concludes with the disadvantages of thyratron control, and objections which have been raised to it. An answer can be found for most of the objections raised.