Present D-C aircraft electric-supply systems

THE multigenerator aircraft d-c electric system represents an important type which has proved its practicability under military-combat conditions. Proper parallel operation is maintained during extreme conditions of unequal generator speeds and accelerations by using an old but heretofore little-used method, which was first suggested and demonstrated for this application by L. W. Thompson. The successful parallel operation, therefore — the reliability and flexibility of the electric-supply system — is made possible chiefly by the use of voltage regulators, which provide for load division as well as voltage constancy. It was natural that difficulties initially experienced in service were not always clearly understood, and that the equipment and installation in the early stages did not have characteristics which would allow the system to operate with its greatest capabilities.¹ However, with experience and study the causes of these difficulties were determined and remedial measures taken. These changes, although only minor individually, when put into effect collectively, made for a considerable improvement in system performance. The result has been a more reliable system requiring less attention from the crew — a factor of paramount importance for a military plane. This improved reliability in turn contributes to the assignment of more functions to the electric system.