When transformer starts to work, the coil will produce alternating current and flux is also alternating. The iron core would produce induced current in varying flux. The iron core produce induced current which is perpendicular to the flux direction and circulate in the plane. So we call it eddy. Eddy loss also make iron core heat. To decrease eddy loss, the iron core is made of silicon steel sheet laminated. The eddy in the narrow loop and pass through the small section to enlarge the resistance of eddy access. At the same time the silicon also make the specific resistance increased to decrease the eddy. To decrease the eddy, the thickness of silicon steel sheet is thin, the joint slip is narrow, the result is better. It not only decrease the eddy loss and temperature rise, it also save the silicon steel sheet material. It doesn’t consider one side to make iron core. Because to make iron core need more time and decrease the active section of iron core. So when we make iron core of transformer, we need to consider actual situation to decide the proper size.
