Silicon Steel Ei Lamination Transformer Core

silicon steel ei lamination transformer core/transformer lamination cutting

Commonly used transformer iron cores are generally made of silicon steel sheet. Silicon steel is a kind of silicon (silicon also called silicon) steel, and its silicon content is 0.8 to 4.8%. The transformer iron is made of silicon steel The core is because silicon steel itself is a magnetic substance with strong magnetic permeability.In the energized coil, it can generate a large magnetic induction intensity, which can reduce the size of the transformer.

We know that the actual transformer always works in the AC state, and the power loss is not only in the resistance of the coil, but also in the iron core under the alternating current magnetization. The power loss in the iron core is usually called "iron loss". 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 the existence of hysteresis during the magnetization of the iron core. The hysteresis loss of the iron core used as a transformer is small, which can greatly reduce the degree of heat generation.
Since silicon steel has the above advantages, why not use a single piece of silicon steel as the 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 operating, there is an alternating current in the coil, and the magnetic flux it generates is of course alternating. This changing magnetic flux is in An induced current is generated in the iron 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 loss also heats the iron core. To reduce eddy current loss, the iron core of the transformer is used The silicon steel sheets insulated from each other are stacked to make the eddy current in a narrow and long loop, through a smaller cross-section, to increase the resistance of the eddy flow path; at the same time, the silicon in the silicon steel increases the resistivity of the material and also reduces The effect of small eddies.

For the iron core of the transformer, cold-rolled silicon steel sheets with a thickness of 0.35mm are generally used. According to the size of the iron core, it is cut into long pieces, and then overlapped into the shape of "day" or "mouth". In the above, if the thickness of the silicon steel sheet is thinner and the spliced ​​strip is narrower to reduce the eddy current, the effect is better. This not only reduces the eddy current loss, reduces the temperature rise, but also saves the material of the silicon steel sheet. But the actual When making silicon steel sheet iron core, it is not only from the above one of the favorable factors, because making the iron core like that, it will greatly increase the working hours, and also reduce the effective cross section of the iron core. Therefore, when using silicon steel sheet to make the transformer iron core, It is necessary to weigh the pros and cons from the specific situation and choose the best size.