Comparison of the Epstein-square and a single-strip tester for measuring the power loss of nonoriented electrical steels

The Epstein-square is used as an internationally accepted standard for the measurement of the iron loss and permeability of electrical steels. In this investigation the power loss of nonoriented electrical steels was measured using the Epstein-square and also a single-strip tester. Single-strip testing showed important differences in anisotropy which are not detected using the Epstein-square in the standard way. Furthermore it is shown that the Epstein standard method on measurement can give a false indication of the quality of some nonoriented steels for many applications. Improved test procedures are suggested to overcome these problems.