Recent improvements in the insulation of electrical machinery

The paper constitutes a review indicating the more recent developments in the manufacture and use of insulating materials. A survey of the prominent characteristics of such materials is followed by a summary of process improvements. In handling this subject the authors put forward a strong plea for standardization of nomenclature and of test methods for determining essential properties of insulating materials. The paper is accompanied by eight appendixes, which include examples of standardizing of material terminology and a considerable amount of data obtained by test methods as adopted by the E.R.A.