Partial discharge testing of HV wiring harness for airborne displays

More flexible helmet-mounted CRTs are now being developed, presenting new design challenges. For example, high voltage leads for helmet-mounted displays must incorporate a quick release, load-break mechanism to accommodate pilot ejection. The potential presence of flammable vapors resulted in an arc-suppressing, quick-disconnect, connector design which opens the high voltage via hermetically sealed contacts. The sealed contacts contain any arcing and break the circuit before the connector separates. A prototype harness for a helmet mounted display (HMD) and tracker has been designed jointly by the University of Dayton Research Institute and Reynolds Inc. under the sponsorship of Armstrong Laboratory. The harness routes two 13.5 kilovolt rated direct current leads along with other wiring via the quick-disconnect connector. The high voltage and compact design motivate concerns about partial discharge degradation of the insulation, particularly at sub-atmospheric pressures. The harness has been tested at simulated altitudes up to 70000 feet, at operating voltage. Results of the testing at Wright Laboratory are presented.