Transient characteristics of D-C motors and generators

SINCE THE FIRST installation of electric power on board the USS Trenton in 1883, the United States Navy has always been a major user of d-c power. After the introduction of 440-volt alternating current into the Navy with installations on the Farragut-class destroyers in 1932 there was still a continued use of a sizable amount of direct current. All vessels having a-c systems required some direct current for powering excitation supplies, searchlights, battery chargers, and interior communications. Although alternating current had become the accepted standard, smaller vessels, such as landing craft and patrol craft, retained d-c systems in the interest of simplicity. Other vessels, such as large tenders, repair ships, tugs, and submarines, had relatively large d-c power plants installed for electric propulsion purposes.