STP327

    Corona Detection Techniques as a Nondestructive Method for Locating Voids in Filament-Wound Structures

    Published: Jan 1963


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    Abstract

    When high voltages are applied across electrical insulating material coronalike discharges will occur in the small gaps or voids within the insulating material, producing radio noise, or corona pulses, as a result of the high-frequency components in the current generated by the discharge. These voids within the electrical insulating materials can be found by probing the surface of the materials with high voltage and determining the areas that produce corona. Some indication of the size and shape of the void can also be obtained by studying the characteristics of the corona pulse being produced within the void. Thus, corona test methods can be used to locate voids within dielectric materials and to indicate the size and shape of such voids. Moreover, because corona testing is nondestructive, its usefulness as a tool for the filament-winding industry becomes very apparent.

    The various corona detection circuits are reviewed and the feasibility of corona test methods as a nondestructive test for locating voids or flaws within filament-wound structures are discussed. The various types of corona detectors used for flaw detection, the present art in relating the size and shape of the void to the corona pulse characteristics, and the areas where investigation and development are necessary in order to perfect the test method are pointed out.


    Author Information:

    Lindsay, E. W.
    Senior Engineer, Westinghouse Electric Corp., Materials Research Laboratories, East Pittsburgh, Pa.

    Works, C. N.
    Senior Engineer, Westinghouse Electric Corp., Materials Research Laboratories, East Pittsburgh, Pa.


    Paper ID: STP44443S

    Committee/Subcommittee: D20.70

    DOI: 10.1520/STP44443S


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