Problems to consider in applying selenium rectifiers

THE PROPER selection of selenium rectifier stacks for d-c power supplies in large scale industrial or military projects usually requires considerably more information than can be obtained from a manufacturer's catalog. The most important problem in applying selenium rectifiers arises in connection with the life requirements for the application. Test data indicate that the life expectancy of selenium rectifiers is affected by the different manufacturing techniques used by the suppliers. With the present art of manufacture, the life expectancy tends to decrease as the cell voltage rating is increased. In addition, the life is affected by the current density and the temperature at which the selenium cells are operated.