The difference between foil-wound reactors and wire-wound reactors

What is a foil-wound reactor?
The foil reactor is made by winding a sheet of foil with a width equal to the height of the reactor. Under AC conditions, due to the eddy current effect, the current flowing through the foil tends to concentrate at the edge of the foil, resulting in the phenomenon of "flowing out of the foil". The eddy current effect causes the AC resistance of the foil to be much greater than the DC resistance, and the AC power consumption to be much higher than the DC power consumption. To reduce the eddy current effect of the foil reactor, in actual design, it is usually split in the height direction of the reactor and then combined in series and parallel. These measures often require special processes to complete. However, as the number of splitting segments increases, although the eddy current effect is reduced to a certain extent, the braking resistance increases exponentially. It does not play a role in reducing power consumption. The above reasons have greatly limited the manufacturing and application of foil reactors.

Which is better, the foil winding or the wire winding performance of the reactor? What are the differences between them?
The skin effect of the wire-wound type is high, suitable for low-frequency alternating current or for current retention. It is made by winding one or more wires together and is mainly used for low voltage and small capacity. Wire-wound reactors generally are used for currents below 60A and are generally used in series with power capacitors in reactive power compensation systems.
The skin effect of the foil winding is low, making it suitable for high-frequency alternating current. It is generally used for the input and output of frequency converters. The foil winding uses copper foil or aluminum foil with high conductivity as the conductive material. The thickness of the copper foil or aluminum foil is about 0.1 - 2.5 mm. It has good electrical strength, uniform voltage distribution under impulse gradient, and is convenient for winding.
The so-called skin effect: For alternating current in conductors, the current density near the surface of the conductor is greater than that inside the conductor. As the frequency of the current increases, the skin effect causes the resistance of the conductor to increase and the inductance to decrease. In fact, the current inside the wire is very small. The current is concentrated in a thin layer near the surface of the wire. As a result, its resistance increases, and the increase in the resistance of the wire leads to an increase in its loss power. This phenomenon is called the skin effect. The higher the frequency, the more significant the skin effect is.
The main conductor materials include aluminum wire, copper wire, aluminum foil, and copper foil. Among them, aluminum wire has the lowest cost, while copper foil has the highest cost. In terms of material differences: copper winding has much better performance than foil winding; in terms of skin effect: the surface of the electronic conductor of foil has stronger ability to withstand overcurrent; in terms of value: wire winding has higher stability than wire foil winding; in terms of temperature rise: the temperature gradient of wire winding is lower and its thermal stability is better. In terms of appearance: foil winding is more aesthetically pleasing for large current, while wire winding has better flatness for small current and the appearance is consistent.
Overall, for the reactors used in reactive power compensation systems, wound-type reactors are more suitable. Considering their electrical performance and cost factors, Jinneng Electric is a high-tech company specializing in the research and development, design, production, sales and service of a series of products such as low-voltage power capacitors , filtering reactors (using Baowu silicon steel sheets and copper windings, with a temperature rise of 45K), reactive power compensation controllers, thyristor switches, static var generators, and active power filters.