Evaluation procedures for electrical insulating varnishes

In order to manufacture high quality electrical equipment for our customers and to maintain a strong competitive position in the electrical industry, it has always been necessary to maintain very rigid standards in the selection of new insulating materials for electrical equipment. This paper discusses the best evaluation techniques which have been developed or adopted during the past ten years and are being used in the selection of insulating varnishes for Class H electrical apparatus. This paper also contains a description of the testing methods used in the evaluation of varnishes and includes data which illustrates these methods. These methods can be modified to include all classes of insulating varnishes.