"Thermal Aging of Enameled Wire and Insulating Varnish"

This paper describes and tabulates the results obtained from a high-temperature modification of both the well-established AIFE #57 method and the proposed Curved Electrode method for evaluating wire enamels and insulating varnishes. In most previously reported work, based on both the Voltage Breakdown and Proof Voltage methods, voltage measurements were recorded at - or near room temperature. Since elevated temperature permit a closer approximation of the actual condition that develop in an operating motor or transformer, a more reliable evaluation of the insulation under investigation should result.