The economic flux density in large supply transformers

Technical developments may at any time make it possible to increase the working densities in our electrical machines, and so enable a larger output to be obtained from a given frame-size and weight of active materials. This paper assumes that an increase of transformer flux density is technically feasible, and tries to discover whether it is economically desirable. Only a single situation, and only two (fairly large) sizes of transformer such as would be used on the lower-voltage sections of the Grid, are examined. The results are emphatically against any such increase, and in favour of lower densities than those in use at present. The economics of higher-grade steel is briefly examined.