Assessment of grain-oriented transformer sheets with respect to transformer noise

Abstract

Sheet mills supplying transformer sheets usually specify the ac magnetostriction amplitude as an acoustical characteristic. With grain-oriented sheets this is no longer adequate; the assessment of the sheets can be greatly improved by focussing attention on measurements of the A-weighted vibration velocity. The measurements can be carried out with existing test equipment. The importance now attached by transformer manufacturers to the magnetostrictive properties of core sheets increasingly puts sheet suppliers under an obligation to specify the A-weighted vibration velocity.