Mutual inductance current transducer, method of making, and electric energy meter incorporating same

Abstract From the Canadian patent

54,408, ABSTRACT, A mutual inductance differential current transducer employs a toroidal coil mounted coaxially and generally centrally of the length of an alternating current conductor with a conductive sheet therebetween surrounding the conductor and of substantially the same length and in insulated relationship from the conductor. The axial length of the coil is less than approximately one-third the length of the conductor, and the toroidal crosssection has a longer leg parallel to the axis of the conductor and a cross-sectional area eliminating the need for external capacitive and magnetic shielding. The coil is wound with an integer number of layers of the same number of turns per …