1500°F filament-wound electrical wire insulation

摘要

By the way of introduction to you who are not familiar with Sandia Laboratory and its operations, I will give you a few pertinent facts about Sandia. We are located in the eastern edge of Albuquerque, New Mexico, and work with the Los Alamos Scientific Laboratory in the design and development of hardware for nuclear bombs and missiles. In general this hardware may be described as ballistic cases, arming and fusing and firing systems, testing and handling equipment associated with nuclear weapons. We have another laboratory located in Livermore, California, which does similar work with the Lawrence Radiation Laboratory at Livermore. Our beginning was back in 1949 when President Truman asked the Bell System to accept a no-fee, no-profit contract with the Government to perform this task. Our accomplishments to date have been due to the careful attention to the series of unique and demanding requirements. Nuclear weapons must 1. be extremely safe to handle, for an unintential detonation would be catastrophic; 2. they must be highly reliable — they must work the first time they are energized after lying in storage for many years; and 3. they must be able to withstand environmental extremes of mechanical shock, temperature, changes, moisture, vibration and acceleration. While most of our work is devoted to nuclear weapons for the government, Sandia Laboratory is now releasing more and more unclassified information for non-military applications. Our 1500°F insulated wire was developed for a specific application within our system; now we fully recognize that these requirements do not represent general use conditions for all wire insulations, but we hope that by sharing this technology with electrical manufacturers that some of the aspects of this process will be useful to your applications. The general design parameters given to us at the beginning of this project were: that the internal hook-up wire to be used in an inertial switch must maintain a dielectric- strength of 200 volts per mil during 1500°F exposure; it must be flexible to permit 90° bending prior to the elevated temperatures; and it must be contamination-free so that it will not outgas or emit particles which could contaminate switching contacts during our operational temperatures between −65°F and 200°F. This process development project has evolved around a thermal barrier silicone rubber (TBS 758)® developed by General Electrical Silicone Products Department, and other materials added for reinforcement and processing aids. The ultimate reinforcing material has proven to be boron nitride long staple fibers (BNF) produced by the New Products Division of Carborundum Company.