Contribution of magnetostriction to transformer noise

An important source of transformer noise is magnetostrictive vibration of the magnetic core. This paper outlines some important effects of mechanical building stress on magnetostriction. Harmonic analysis of magnetostriction is necessary to quantify its influence on acoustic noise but it implied here that the most important magnetostrictive parameter has not yet been identified. A route is proposed for obtaining a definite, quantified relationship between defined magnetostrictive characteristics of core laminations and noise by systematically assessing noise and vibration modes of simple, small transformer cores.