Electrical Insulation Reliability [Dakin´s Corner]

Most of us who are in the field of electrical insulation research, development, manufacture, or application are probably impressed with the value of what we do; but we may not always recognize the numerous, critical characteristics of our insulation that can adversely affect their reliability in service-and, ultimately, the reliability of the apparatus of which the insulation is a part. This column and some succeeding ones will attempt to point out more important insulation characteristics which, if inadequate, can result in insulation failure. This topic divides itself into two principal categories: 1) Initial insulation characteristics which may be marginal or inadequate to meet the demands of the initial test prior to service or the manufacturing application. 2) Characteristics that develop after aging in service for some period of time. If these characteristics are inadequate and unreliable, they can lead to equipment failure and repairs which could be more costly than the original price of the insulation.