Manual switches for aircraft

In the design and application of electrical control equipment the problem of obtaining complete field data and requirements is always present in some degree. The problem is acute in branches of the electrical industry supplying aircraft control. Three factors contribute to the difficulty: 1. The tremendous engineering effort centered in the aircraft industry causes rapid technical changes that soon make accumulated data obsolete. 2. Technical data on utilization devices are not always available to either the aircraft or electrical manufacturer. The mushroom growth and technical advance of the aircraft industry have, in some cases, outdistanced laboratory equipment and personnel capacity so the data an electrical-control manufacturer would like to have are simply not available. 3. The secrecy surrounding many aircraft developments blocks the passing of information from the aircraft manufacturer to the electrical manufacturer. The electrical-control manufacturer can meet this problem, in part, by making available complete performance data on switching equipment offered for sale. Properly chosen, these data enable the aircraft engineer to match control means with his electrical utilization device requirements. In the preparation of such data the following considerations are of primary importance to both the user and producer of switches. The functions of an aircraft switch may be classed broadly as follows: 1. To establish a circuit. 2. To maintain a circuit. 3. To interrupt a circuit. Performance of these functions is importantly affected by the following characteristics of the load: (a). Inrushes. (b). Inductance. (c). Current. (d). Voltage.