Abstract
The purpose of this study is to solve the structural noise level caused by electromagnetic force of coils, for front loading design the transformer noise. To research the phenomenon of the electromagnetic induced vibration, firstly, we observed radial and vertical direction vibration of coils, and we confirmed both direction vibration amplitudes almost same order. So, for the analysis of the electromagnetic induced vibration noise, we found the continuum mechanics model is necessary, and old analysis model using mass and springs, can not simulate the vibraion. Secondly, we made the proposed model of continuum mechanics and old model using mass and springs for a transformer, and calculate the vibration modes and responses of coils. The calculation results of the proposed model was good agreement with experimental results, but the old model was not good agreement. At last, we calculated the vibration level with the proposed model of the transformer and the tank, and the vibration level of the tank by coupled fluid analysis and structure born sound analysis. And we calculated the noise level around the tank which equipped the transformer with the boundary element analysis. Considering the vibration mode differences between calculation model and practical model, we could analyze the noise level within 5dB error. And we become able to get the highest level if the vibration mode agree with 2 times of the driving frequency when we design the transformer.
