Fast numeric calculation of massive conductor 3D magnetic field

Preliminary results, theoretical and experimental, dealing with magnetic field in high current three phase net are presented. The simple formula was derived for magnetic field of thin conductor of finite length. According to the formula the flux density decreases at long distance by the second power of distance. The formula makes possible fast numerical calculation of the 3D magnetic field of massive conductors in three phase net. Then the animation of the field flux density is not a problem. The agreement with preliminary experiment is satisfactory, if we take into account a relatively low accuracy of the preliminary experiment. The simple model can be extended by skin-effect and eddy currents effects to be more realistic and allow the estimation of the force between conductors, for instance