JPS6447008A - Current transformer - Google Patents

Abstract

PURPOSE:To contrive reduction in parasitic inductance by a method wherein the middle leg of the primary winding passes through the center part of a core, the primary winding is constituted by an E-shaped conductor formed by short-circuiting a pair of external legs positioned outside the core, one lead-out wire is provided to the middle leg, and the other lead-out wire is provided to the outer leg. CONSTITUTION:The middle leg 4a of the E-shaped conductor 4 of the primary winding 2 is a little shorter in length than the outer legs 4b and 4c, and a tabular conductor 4d is provided in right-angled direction on the end part of the middle leg 4a. The middle leg 4a of the E-shaped conductor 4 penetrates the center of a toroidal core 1b, and the outer legs 4b and 4c are arranged in such a manner that they are positioned on the outside. When the primary current I is supplied from the leg 3a of a T-shaped core 3, it passes the arms 3b and 3c of the conductor 3, passes the outer legs 4b and 4c of the E-shaped conductor 4, passes the middle leg 4a, and the primary current flows out from the conductor 4d, magnetic field is generated, but as the magnetic field in the windows 5a and 5b, formed by the arms 3b and 3c and each leg of the E-shaped conductor 4, face in the opposite direction with each other, and thus direction makes a round of the toroidal core 1b. As the magnetic field on the part aparted from the primary winding is facing reversely, they are made weak each other, and the magnetic flux generating in the air gas other than the shield case 1e and the toroidal core 1b is reduced.