Air cooled transformer axial cooling channels - has dimensions chosen to prevent air columns resonating at magnetostrictive excitation frequency

摘要

An air cooled transformer which is made with one or several axial cooling channels. The iron core is wound by cylindrically shaped windings or winding sections and the cooling channels run between the winding sections. The geometric dimensions of the cooling channels are such that the natural frequencies of the air columns in the separate cooling channels do not coincide with the magnetostrictive excitation frequency. There are discontinuities in the air columns in the air channels which will prevent the formation of standing sound waves of coresponding frequencies. There are also radial gaps (4) in the cooling channel adjacent to the windings. The cross-section of the cooling channel is trapezoidal.