What are the merits and abuses of the present method of thermal classification of insulating systems?

"Temperature classification" and "thermal evaluation" need to be better understood by everyone in order to avoid abuses and to achieve satisfactory and economical use of electrical insulation in equipment. This can be best achieved by careful reading of AIEE No. 1 and its related appendices (No. 1d and No. 1e). This paper will quote copiously therefrom.