Advantages and Functions of Core Type Transformer
Let us know the advantages of the core transformer.
The actual transformer always works in the AC state, and 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 hysteresis in the magnetization process. The magnitude of this loss is proportional to the area enclosed by the hysteresis loop of the material. The hysteresis loop of silicon steel is narrow, and the core hysteresis loss of the transformer is small, which can greatly reduce the degree of heat generation.
The advantages of core type transformer are that the chip core can reduce another type of iron loss - "eddy current loss". 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 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 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 eddy current path; at the same time, the silicon in the silicon steel increases the resistivity of the material to reduce eddy currents. As the core of the transformer, a 0.35mm thick cold-rolled silicon steel sheet is generally used. According to the size of the required core, it is cut into long pieces and then overlapped into a "the character-ri" shape or a "the character-kou" shape. In theory, if the eddy current is reduced, the thickness of the silicon steel sheet is thinner, the spliced strip is narrower, and the effect is better. This not only reduces the eddy current loss, reduces the temperature rise, but also saves the silicon steel sheet. However, in fact, when making a silicon steel sheet core, it is not only based on the above advantageous factors. Because the iron core is produced in that way, the working time is greatly increased, and the effective cross section of the iron core is also reduced. Therefore, when using a silicon steel sheet to make a transformer core, it is necessary to weigh the pros and cons from the specific situation and choose the best size. The core transformer is made according to the principle of electromagnetic induction. There are two windings on the closed core column, including one primary winding and one secondary winding. When the original winding is connected with the AC power supply voltage, the primary winding establishes magnetic potential. An alternating main flux is generated in the core under the action of the magnetic potential. The main magnetic flux is closed in the iron core through the first and second windings at the same time, and the induced electromotive force is generated in the first and second windings respectively due to electromagnetic induction.
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