The no-load loss in the transformer loss, that is, the iron loss, mainly occurs in the UI laminate of the transformer core, mainly due to the loss caused by the alternating magnetic field lines generating hysteresis and eddy currents through the iron core. The earliest material used for the transformer core is soft wrought iron which is easy to magnetize and demagnetize. The transformer core is made of iron wire instead of monolithic iron, in order to overcome the magnetoresistance caused by periodic magnetization in the magnetic circuit. Loss and eddy currents due to the magnetic flux cut by the core.
The iron core made of wire harness can effectively reduce the cross-sectional area of the eddy current path. Later, it was found that adding a small amount of silicon or aluminum to the iron can greatly reduce the magnetic path loss, increase the magnetic permeability, and increase the resistivity and reduce the eddy current loss. . After many improvements, the UI laminate of the transformer core was replaced by a 0.35 mm thick silicon steel sheet instead of the iron wire.
In recent years, countries all over the world are actively researching and producing energy-saving materials. The core material of transformers has been developed to the latest energy-saving material - amorphous magnetic material 2605S2, and amorphous alloy iron core transformers have emerged. The transformer made with 2605S2 has a steel loss of only 1/5 of the silicon steel transformer, and the iron loss is greatly reduced.