Nonintrusive Measurements for Detecting Progressive Equipment Faults

The gradual environmental degradation of materials can lead to corrosion and mechanical failures of electrical loads. Vibration and corrosion both contribute to the failure of electrical connections and conductors, and electrical arcs destroy materials in ways that enhance the opportunities for further damage. These failures lead to loss of system capability and the possibility of electrical fires. The signatures of these impending electrical failures, which may occur over weeks or months, can be detected in many systems through nonintrusive electrical monitoring. This article demonstrates techniques for decoding the type of electrical signatures that lead to progressive failure. Example applications of these techniques are illustrated with observations of the degradation and failure of copper-sheathed jacket water (JW) heaters aboard a United States Coast Guard (USCG) vessel. Electrical, material, and vibration analysis are presented to demonstrate the basis for diagnostic electrical signatures.