In a three-phase and three-leg core structure of a core-type transformer comprising three main legs of a substantially circular cross-sectional shape and a yoke of a non-circular cross-sectional shape for magnetically connecting the three main legs, each of the three main legs having a cross-sectional area substantially equal to the cross-sectional area of the yoke, wherein at least joints between the steel plate laminations of a center main leg and the adjoining steel plate laminations of the y...

A single-phase three-legged core for a core type transformer in which a plurality of steel sheets constituting each layer of laminations of a main leg are jointed at their diagonally cut sides to corresponding sides of a plurality of steel sheets constituting each layer of laminations of yokes to form a plurality of joints. At the inner corner portion of each joint, a recess is provided along the main leg or yoke steel sheet having a greater width than the other, so that a plurality of main leg ...