Commonly used transformer કોરs are generally made of silicon steel sheets. Silicon steel is a kind of steel containing silicon (silicon is also called silicon), and its silicon content is 0.8 to 4.8%. Silicon steel is used as the આયર્ન core of the transformer because silicon steel itself is a magnetic substance with strong magnetic permeability. In the energized coil, it can generate a large magnetic induction intensity, thereby reducing the volume of the transformer.

We know that the actual transformer always works in the AC state, and the power નુકસાન is not only in the resistance of the coil, but also in the આયર્ન core magnetized by the alternating current. The power નુકસાન in the iron core is usually called “iron loss”. The iron loss is caused by two reasons, one is “hysteresis loss” and the other is “eddy current loss”.

Hysteresis loss is the iron loss caused by hysteresis during the magnetization process of the iron core. The magnitude of this loss is proportional to the area surrounded by the hysteresis loop of the material. The hysteresis loop of silicon steel is narrow and small, and the hysteresis loss of the iron core of the transformer is small, which can greatly reduce the heat generation.

Since silicon steel has the above advantages, why not use a whole piece of silicon steel as the iron core, but also process it into a sheet?

This is because the sheet iron core can reduce another kind of iron loss – “eddy current loss”. When the transformer is working, there is alternating current in the coil, and the magnetic flux it produces is of course alternating. This changing magnetic flux induces a current in the core. The induced current generated in the iron core circulates in a plane perpendicular to the direction of the magnetic flux, so it is called eddy current. Eddy current losses also heat the core. In order to reduce the eddy current loss, the iron core of the transformer is stacked with silicon steel sheets insulated from each other, so that the eddy current passes through a smaller cross section in the narrow and long circuit, so as to increase the resistance of the eddy current path; at the same time, the silicon in the silicon steel makes The increased resistivity of the material also acts to reduce eddy currents.

As the iron core of the transformer, cold-rolled silicon steel sheets with a thickness of 0.35 mm are generally selected. According to the size of the required iron core, it is cut into long pieces, and then overlapped into a “day” or “mouth” shape. Theoretically speaking, in order to reduce eddy current, the thinner the thickness of the silicon steel sheet and the narrower the spliced ​​strips, the better the effect. This not only reduces the eddy current loss and temperature rise, but also saves the material used for silicon steel sheets. But in fact when making silicon steel sheet core. Not only starting from the above-mentioned favorable factors, because making the iron core in that way will greatly increase the man-hours and also reduce the effective cross-section of the iron core. Therefore, when using silicon steel sheets to make transformer cores, it is necessary to proceed from the specific situation, weigh the pros and cons, and choose the best size.