FAQ | Feb 15,2023
First of all, we know the first what is the eddy current. Because of the change of magnetic flux in the core, the transformer will also generate induced current, which exists in the core is called eddy current.
So how do we reduce the eddy current? We can reduce the strength of the magnetic field. Or we can reduce the plate area. Or we could change the rate of change of flux. In most cases, however, it is impossible to reduce the strength of the magnetic field or change the rate of change of the flux. At the same time, reducing the metal area is not an ideal method. For example, reducing the size of a 420kV transformer due to eddy current losses is not a wise choice. Huge scale is a rating requirement. Further reductions are impossible.
This is the core of a transformer (shown above) surrounded by a coil carrying AC current. This creates an electric current in the core, as we can see. Since this core provides very low resistance, it turns red due to the heat generated by the eddy. Therefore, to reduce this eddy current loss, the resistance of the magnetic core must be increased. So, let’s divide this core into two parts. Let’s put an insulating layer between the two parts.
Now, the resistance has definitely increased. The induced voltage in each section is now half of what it was before.As a result, the eddy current will also decrease significantly. If the core is further subdivided, eddy current loss will gradually decrease. This is why the cores of transformers or AC motors and generators are always laminated.
--- END ---
COPYRIGHT © HEYI ELECTRICS SOLUTION
