During the First World War, the Company’s entire facilities were turned over to the U.S. Navy and U.S. Army Signal Corps for the production of special resistors, charging panels, and controls.

During the war, an urgent demand for resistors exceedingly light in weight fostered the development of Ward Leonard Ribohm® resistors. Made of metal ribbon, channeled, and bent into a “V” shape, these ribbon resistors were first applied on portable battery charging panels designed for the U.S. Army Signal Corps to charge radio batteries used along advanced lines of communications.

The Ward Leonard System was applied to railway locomotive engines during the war.