Patent ID: 8339234
Filing Date: 2012-12-25
Classification: H01F

Abstract:
1. Inductance coil, in particular an inductance coil without an iron core for use in electric power grids, comprising at least two cylindrical winding layers ( 1 ), which are disposed concentrically with respect to a coil central axis ( 7 ) and are connected electrically in parallel, and at least one means for reducing or minimizing sound emissions produced during the operation of the inductance coil, wherein at least the outermost winding layer ( 1 ) is designed as a current-conducting, acoustic shield winding ( 18 ) opposite the adjacent winding layer ( 1 ) in the direction of the coil central axis ( 7 ), wherein said acoustic shield winding ( 18 ) is dimensioned electrically such that it is designed for the transmission of a current intensity, which is between 0.1% to a maximum of 50% of the current intensity, which has to be transmitted by the adjacent winding layer ( 1 ) in the direction of the coil central axis ( 7 ).