Higher-voltage D-C Aircraft Electric Systems

Many of the advantages of 115-volt d-c aircraft electric power are presented with frequent comparisons to 24-volt direct current and 208/120-volt 400-cycle three-phase alternating current. System reliability is emphasized. Weight comparisons favorable to 115-volt direct current are shown for power generation, distribution, and load components. Problems concerning the use of the two high-voltage systems are discussed and compared. The popular belief that 115-volt d-c switching and commutation is unsatisfactory at high altitudes is refuted. It is concluded that 115-volt direct current is the lightest and most practical of the proposed electric systems for both medium and large airplanes.