Recent development in grain-oriented electrical steel with low magnetostriction

For precise evaluations of magnetostriction properties, a new magnetostriction measuring system using a laser vibrometer was developed. Frequency analysis of magnetostriction under non-sinusoidal magnetization revealed a nonlinear relation between harmonics in flux and those in magnetostriction. Transformer core vibration was investigated in order to clarify the relations between magnetostriction and transformer noise and to realize low-noise transformers. Resonance was proved to have an important role for core vibration. Domain-refined, grain-oriented electrical steel, which fulfills low loss and low magnetostriction properties simultaneously, is also explained.