Metallic rectifiers for shipboard electric systems

PRIOR TO 1932, all Navy ships had d-c electric plants for supplying power to electric auxiliaries and lighting systems. As the size of electric plants grew, it was recognized that the adoption of a-c systems for shipboard electric plants offered distinct advantages. At the present time, all of the newer Navy shipboard electric generating plants, except for some small ships, are designed to provide 450 volts alternating current. However, some electric auxiliaries used on board ship require direct current for their operation. Direct current is needed for such applications as degaussing, battery charging, carbon-arc searchlights, generator excitation, circuit breaker and reactor control circuits, cathodic protection, guided-missile servicing, aircraft starting and servicing, etc.