What is the Function of the Core？

What is the Function of the Core？

Transformer cores are mostly made of silicon plates. The actual transformer always operates in the AC state, and the power loss is not only on the resistance of the coil, but also in the core magnetized by the alternating current. The power loss in an iron core is usually called “iron loss”, and iron loss is caused by two factors: “hysteresis loss” and “eddy current loss”.

Hysteresis loss is the iron loss caused by hysteresis phenomenon in the magnetization process of iron core, and 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 smaller, so the hysteresis loss of the core of transformer is smaller, and the heating degree can be greatly reduced. The sheet core reduces another type of iron loss, “eddy current loss”. When the transformer works, there is alternating current in the coil, and the magnetic flux produced by it is of course alternating. This varying flux generates an induced current 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 losses also cause the core to heat up. In order to reduce the eddy current loss, the transformer core with each other insulated silicon steel sheet stacked, so that the eddy current in the narrow and long loop, through a smaller section, to increase the resistance of the eddy current path; At the same time, the silicon in the silicon steel increases the resistivity of the material and also plays a role in reducing the eddy current.