The single-phase silicon steel composite itself is also an electrical conductor, and an induced current is generated in the iron core under the action of the alternating magnetic flux. This is unavoidable. If the iron core is a whole, it is equivalent to a large-area conductor, the circuit is short, and its resistance value is very small. Although the induced voltage is not high, the current is large.
However, after the insulating lacquer is applied between each of the single-phase silicon steel composites, the cross section of the core is divided into a plurality of small-section conductors. Thus its resistance becomes larger. Therefore, the painted iron core, although there are eddy current losses, is also much smaller.
Therefore, the thinner the silicon steel sheet, the smaller its loss. Under normal circumstances, the insulating paint of the single-phase silicon steel composite surface has been painted before leaving the factory. When the transformer is working, there is an alternating current in the coil, and the magnetic flux it generates is of course alternating. This varying magnetic flux produces an induced current in the core.
The induced current generated in the single-phase silicon steel composite core is circulated 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 iron core of the transformer is laminated with silicon steel sheets insulated from each other, so that the eddy current flows through the narrow cross section to increase the electric resistance on the vortex flow path; at the same time, the silicon in the silicon steel makes The resistivity of the material increases and also acts to reduce eddy currents.http://www.chenglion.com/