Patent ID: 6429765
Filing Date: 2002-08-06
Classification: H01F

Abstract:
A controllable inductor comprising at least a tubular core, a main winding wound substantially tangentially around said tubular core and a control winding passing axially through said tubular core, a yoke of a material having a high magnetic permeability, said yoke extending outside the core and the main winding and together with the core forming a closed loop having at most insignificant air gaps for a magnetic flux generated in the core by a current in said main winding, wherein the control winding comprises first plates extending axially through the core and being of a conducting material; wherein the control winding also comprises second plates (8) extending outside the core and the main winding and being of a material having a good electric conductivity, said plates being electrically connected to said first plates (6) and adapted together therewith form closed loops for a current flow in the first plates through the core; and furtherwherein a yoke comprises plates (18) being arranged to extend substantially in parallel with each other at each end of the core and being with their large surfaces thereof in parallel with a plane defined by a radius of the core (3) and the axis of the core, that said yoke plates have an edge (21) thereof located in the immediate vicinity of the respective core and so as to receive the main magnetic flux from the core without any substantial air gap therebetween, and that said second control plates (8) are arranged in a space between yoke plates arranged side by side and have substantially the same direction in the room as the yoke plates, so that the yoke plates and these control plates form a sandwich construction; and being connectable to a multiphase alternating-current network and it has one core (3) and one main winding (1) for connection to each phase.