Magnetic core for current transformer, current transformer and watt-hour meter

摘要

A current transformer core made of an alloy having a composition represented by the general formula: Fe 100-x-a-y-c M x Cu a M' y X' c (by atomic %), wherein M is Co and/or Ni, M' is at least one element selected from the group consisting of V, Ti, Zr, Nb, Mo, Hf, Ta and W, X' is Si and/or B, and x, a, y and c are numbers satisfying 10 ‰ x ‰ 50, 0.1 ‰ a ‰ 3, 1 ‰ y ‰ 10, 2 ‰ c ‰ 30, and 7 ‰ y + c ‰ 31, respectively; at least part or all of the alloy structure being composed of crystal grains having an average particle size of 50 nm or less.