The economic rating of motors and transformers and the economic flux density in large supply transformers

Physical and economic ratings are compared, and the scope and limits of economic choice are discussed and illustrated. A method of economic selection is proposed through the use of larger standard machines, and a technique is developed for investigating the economy of changes in rating. Tables of data and results are given at the end of the paper, and the methods employed in these tables are explained in some detail. The results are expressed in the form of an ¿economic advantage¿ obtainable through under- or over-running, and show the former to be highly advantageous in a large number of cases. Methods of implementing the results are discussed.