Patent ID: 8154373
Filing Date: 2012-04-10
Classification: H01F

Abstract:
1. A current transformer apparatus for fault powering electronics coupled to the current transformer apparatus and for sensing a range of currents, the current transformer comprising a core including a plurality of solid laminations and a plurality of gapped laminations arranged back-to-back in a stack, wherein all of said plurality of gapped laminations are arranged back-to-back and all of said plurality of solid laminations are arranged back-to-back, each of the solid laminations having a central opening and each of the gapped laminations including a central opening and a gap or a notch formed along the surface of the gapped lamination, the number of the gapped laminations and the gap dimensions being selected to retain fault powering for solid-state electronics coupled to the current transformer and to sense the range of fault currents in response to a primary current being applied to a wire wound around the core, wherein the range of currents includes a lower current threshold and an upper current threshold, the ratio of the upper current threshold to the lower current threshold being at least 100:1.