When stacking transformer cores, there are three different seam methods. One is direct seam, which is characterized by convenient processing and lamination, and large overlapping area. Therefore, the stacked core structure has good strength and overall Strong, not easy to deform, but can only be used for hot-rolled silicon steel sheet. For example, it is used for cold-rolled oriented silicon steel sheet with good magnetic properties in the rolling direction. Since the magnetic flux at the joint does not pass in the rolling direction, the magnetic properties are deteriorated, resulting in an increase in no-load loss.
The other is a semi-straight and semi-oblique joint, which is used for cold-rolled oriented silicon steel sheet. The characteristic of this joint is that the direct joint and the oblique joint appear alternately in the core lamination, and the width of the core post and the iron yoke are the same At the time, the oblique seam is 45 ° lapped area accounts for 50% of the corner, the magnetic performance is significantly improved than the direct seam, the structure is reliable, the shearing and stacking are also convenient, and the silicon steel sheet utilization rate is high. However, because there is still a part of the direct seam, the directionality of the cold-rolled oriented silicon steel sheet is not fully utilized, so the no-load loss of the iron core cannot be reduced to a small extent.
There is another kind of full oblique joint. In order to further reduce the no-load loss of the iron core and make full use of the characteristics of cold-rolled oriented silicon steel sheet, full oblique joint should be used, so that the direction of magnetic flux and the rolling direction of silicon steel sheet Consistently, the core loss is very small. However, this joint process is complicated and the integrity of the stacked iron core is poor.