The commonly used transformer iron core is generally made of silicon steel sheets. Silicon steel is a type of steel containing silicon, with a silicon content of. 0.8%~4.8%. The iron core of a transformer is made of silicon steel 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 the transformer. The power loss of the transformer in AC state not only occurs in the resistance of the coil, but also in the iron core magnetized by alternating current. The power loss in the iron core is usually referred to as' iron loss', which is caused by two reasons: hysteresis loss and eddy current loss.

Hysteresis loss is the iron loss that occurs during the magnetization process of an iron core due to the presence of hysteresis. The size of this loss is proportional to the size of the area enclosed by the hysteresis loop of the data. The hysteresis loop of silicon steel is narrow, and using it as a transformer core has smaller hysteresis loss, which can greatly reduce its heat generation.

When a transformer is working, the magnetic flux generated by alternating current in the coil is of course alternating. The changed magnetic flux induces current in the iron core. The induced current that occurs in the iron core flows in a straight plane, so it is called eddy current and eddy current loss, which also causes the iron core to heat up. In order to reduce eddy current losses, the iron core of the transformer is made of insulated silicon steel sheets stacked together, allowing the current to flow in a narrow and elongated circuit. The Wuxi ventilation duct passes through a smaller cross-section to increase the electrical limit on the eddy current path; At the same time, the silicon in silicon steel increases the resistivity of the material and also reduces eddy currents

The iron core used for transformers is generally made of cold-rolled silicon steel sheets with a thickness of 0.35mm. Cut it into long pieces according to the required scale of the iron core, and then overlap them 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 reduces eddy current losses, lowers temperature rise, and saves materials for silicon steel sheets. However, in practice, when manufacturing silicon steel sheet iron cores. Not only from the advantageous factors mentioned above. Due to manufacturing the iron core in that way, it requires a significant increase in labor hours and a reduction in the cross-section of the iron core. Therefore, when using silicon steel sheets to manufacture transformer cores, it is necessary to weigh the pros and cons based on specific circumstances and select the optimal scale.

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