Non-destructive detection of voids in plastic materials

摘要

A sensitive yet non-destructive method and apparatus for detecting the presence of voids contained within dielectric materials is disclosed which comprises applying a voltage across the dielectric material to create an electric field therethrough, increasing this voltage to create a partial electrical discharge and monitoring the field current to detect the voltage at which partial discharge occurs. When the partial discharge is detected, the voltage applied across the test material is recorded. Reference can then be made to mathematical charts and formulas readily available to determine the size and shape of the detected void.