Ground Power for Aircraft

The increasing use of electric apparatus on aircraft has brought about the need for rather large sources of electric power for these planes while they are on the ground without engines running. The development of these ground power units from the original storage batteries through the makeshift postwar era to the present highly specialized units is traced in this paper. Units from 5 to 60 kw now are used for this purpose. These units consist of portable engine driven sets as well as induction motor driven units for use in the hangars. These units must all be equipped with special voltage controls and with complete radio interference suppression. The larger units are furnished with a great variety of portability, some being self-propelled. These units must be built in 12, 28, and 120 volt direct current as well as 120-volt 400-cycle alternating current.