Direct-water-cooled Germanium power rectifier

SINCE THE DEVELOPMENT of large-area germanium rectifier cells in 1952, over 20,000 kw of d-c power have been installed and are in service. An equally large amount of germanium rectifier units for converting alternating current to direct current are on order with the various manufacturers of this type of equipment. The first commercial germanium rectifier units used a germanium rectifier stack as shown in Fig. 1. The germanium rectifier cell was sealed with lacquer, making it partially impervious to moisture and atmosphere. This stack was then immersed in a tank containing perchlorethylene and connected with other stacks to form a number of 3-phase bridge rectifiers. The tray was then cooled by running tap water through a thin copper tube surrounding the germanium rectifier stacks. Later, the germanium rectifier stacks were installed in a tank and the perchlorethylene recirculated through several tanks and a water-to-perchlorethylene heat exchanger, to remove the losses from the germanium rectifier stacks. A recent tray using this construction is shown in Fig. 2 which forms part of a 65-volt d-c unit at 15,000 amperes.