The function of transformer silicon steel sheet

The commonly used transformer cores are usually made of silicon steel sheets.

Silicon steel is a type of steel made of silicon (also known as silicon), with a silicon content ranging from 0.8% to 4.8%. It is used as the iron core of transformers because silicon steel itself is a magnetic substance with strong magnetic conductivity. In the energized coil, it can generate a large magnetic induction intensity, which can reduce the volume of transformers.

We know that actual transformers always operate in AC state, and power loss is not only caused by the resistance of the coil, but also by the magnetization of alternating current

Inside the iron core below. The power loss in the iron core is usually referred to as "; Iron loss "is caused by two reasons, one is" hysteresis loss "and the other is eddy current loss". Hysteresis loss is the iron loss generated by the magnetic hysteresis phenomenon during the magnetization process of the iron core. The size 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 using it as the iron core of transformers has smaller hysteresis losses, which can greatly reduce its heat generation.

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

This is because the sheet-like iron core can reduce another type of iron loss - "eddy current loss". When a transformer is working, there is alternating current in the coil, and the magnetic flux it generates is of course alternating. The changing magnetic flux generates induced current in the iron core. The induced current generated in the iron core flows in a plane perpendicular to the direction of magnetic flux, hence it is called eddy current. Eddy current losses also cause the iron core to heat up. In order to reduce eddy current losses, the iron core of the transformer is stacked with silicon steel sheets that are insulated from each other, allowing eddy currents to pass through a narrow circuit with a smaller cross-section, thereby increasing the resistance on the eddy current path; At the same time, the silicon in silicon steel increases the electrical resistivity of the material and also reduces eddy currents. The iron core used as a transformer is generally made of 0.35mm thick cold-rolled silicon steel sheets. According to the required size of the iron core, it is cut into long pieces and then overlapped into a Japanese or mouth shape. In theory, to reduce eddy currents, the thinner the silicon steel sheet and the narrower the spliced strips, the better the effect. This not only reduces eddy current losses and temperature rise, but also saves materials for silicon steel sheets. But in reality, when making silicon steel sheet iron cores. Not only from the above advantageous factors, but also because making the iron core in that way greatly increases labor hours and reduces the optimal cross-section of the iron core. Therefore, when using silicon steel sheets to make transformer cores, it is necessary to consider the specific situation, weigh the pros and cons, and choose the right size. Transformers are made based on the principle of electromagnetic induction. There are two windings wound around a closed iron core column, a primary winding and a secondary winding. When the primary winding is falsely supplied with AC power voltage, the primary winding flows with alternating current, establishing a magnetic potential. Under the action of the magnetic potential, the core generates alternating main magnetic flux, which passes through the core simultaneously

Article source: Transformer silicon steel sheethttp://www.cheungshun.com