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An evaluation of the eclypse ESP hand-held standing wave reflectometer

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Abstract

The Eclypse ESP standing wave reflectometer was tested for its ability to locate open and short circuits on pairs of electrical wires. The robust and simple to use hand-held device was shown to operate successfully and quickly on coaxial cables, twisted pairs, shielded cables and pairs of wires within multi-wire looms. For aircraft wire management this offers an improved fault location capability prior to repairs on the flight line or during maintenance. The ESP could also find application in other defence platforms with complex electrical wiring.

Executive Summary

The incidence of faults in the wiring of aircraft is a persistent problem which causes equipment failure and can endanger the life of the platform and its occupants. The Eclypse ESP standing wave reflectometer has been evaluated for its ability to find the location of a short circuit or an open circuit on a pair of wires. An open circuit occurs when a wire breaks and interrupts the connection to the equipment. A short circuit occurs when insulation damage allows the conductors to touch. While the existence of such faults can be readily determined, its location is often difficult to ascertain due to the complexity of aircraft wiring and the fact that the wiring is often inaccessible or hidden within multi-wire looms. A modern aircraft contains some tens of kilometres of wiring and so an aid to wire fault location is highly desirable. Further, aircraft wiring is susceptible to damage from handling and hence any unnecessary disruption of installed wire needs to be avoided. The Eclypse ESP exploits the fact that in many cases the cables are electromagnetic transmission lines which propagate high frequency electrical signals. In the case of coaxial cables and twisted pairs this is intentional as they are designed to transfer signals of this type between avionics equipment. In the case of wires bundled together in a loom the formation of a transmission line is incidental. In both cases the device utilises the fact that a short circuit or an open circuit on a transmission line is a point of reflection for a signal injected by the device. By transmitting signals over a frequency range the device can determine the type of fault and its distance along the wires. Testing in the laboratory showed it to be capable of detecting wire faults in coaxial cables, shielded cable, twisted pairs and a pair of wires in a loom.

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