Kiyoshi Wakimoto, MEIDENSHA CORPORATION
Transformer stations located near residential districts in urban areas are required to use low-noise transformers. Noise generated by iron core vibration (excitation noise) has taken into consideration such factors as reduction of iron core magnetic flux density, improvement of material properties, iron core structure (joints/clamps) and machine deformations as part of the efforts to move forward with noise reduction. When excitation noise becomes quieter, noise accompanying load current (load current noise) sometimes becomes an issue after having been ignored while excitation noise was being dealt with. As part of initiatives for predicting load current noise or noise reduction, we used JMAG for a coil vibration analysis (frequency response analysis) using electromagnetic force (Lorenz force) during current flow as an excitation force. During this lecture we plan to describe the acceleration of vibration generation when energized in air (actual excitation) as measured on an actual model and the results of a numerical analysis on this. We expect this will contribute to enhanced product competitiveness after replication of test results in CAE analysis becomes possible and analysis will be used to examine design parameters.