The commonly used transformer core is generally made of silicon steel sheet. Because the silicon steel itself is a magnetic material with strong magnetic conductivity, in the energized coil, it can produce a large magnetic induction intensity, so that the volume of the transformer can be reduced.
As we know, the actual transformer always works in the AC state, the power loss is not only in the resistance of the coil, but also in the core under the alternating current magnetization. The power loss in the iron core is usually called "iron loss". The iron loss is caused by two reasons, one is "hysteresis loss" and the other is "eddy current loss".
Hysteresis loss is the iron loss caused by the existence of hysteresis phenomenon in the process of magnetization of the iron core. The size of this loss is proportional to the size of the area surrounded by the hysteresis loop of the material. The hysteresis loop of silicon steel is narrow, and the hysteresis loss of transformer core is small, which can greatly reduce its heating degree.
The three-limb iron core is made of oblique cut Grain-oriented, seven-step silicon steel laminations insulated on both sides, guaranteeing low losses and low noise. These values are even improved by laser treatment. It is protected on the surface with a flash-proof varnish in order to prevent the sheet from corrosion and to reduce the noise.
