What causes skin effect in AC currents?

  • #1
Qmavam
14
2
My assumption has been it is the electromagnetic field starting from the center of the wire that pushes the electrons outward.
However, this would also be true of a DC current, but it isn't.
So why does an AC current cause electrons to move toward the skin of a wire?
I don't recall ever seeing this explained.
Thanks, Mikek
 
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  • #2
Qmavam said:
So why does an AC current cause electrons to move toward the skin of a wire?
It does not.
The current starts on the outside surface, and moves slowly into the conductor.

The incident loop of magnetic field, around the wire, causes a current to flow along the wire.
That causes an opposite magnetic field loop, that cancels most of the incident field, which reduces the magnetic field entering the conductor, and so the current stays on the surface.
 

What is skin effect in AC currents?

Skin effect is a phenomenon in which alternating current tends to flow more towards the outer surface of a conductor, rather than evenly throughout the entire cross-section. This is due to the magnetic field generated by the current, which causes the electrons to be pushed towards the outer edges of the conductor.

What causes skin effect in AC currents?

Skin effect is primarily caused by the self-inductance of the conductor. As the current flows through the conductor, it generates a magnetic field around the conductor. This magnetic field interacts with the current, causing it to be concentrated towards the outer edges of the conductor.

Why is skin effect more pronounced at higher frequencies?

Skin effect becomes more pronounced at higher frequencies because the rate at which the current changes direction increases. This results in a stronger magnetic field around the conductor, which in turn pushes the current towards the outer surface more effectively.

How does skin effect affect the resistance of a conductor?

Skin effect increases the effective resistance of a conductor at higher frequencies, as the current is concentrated towards the outer edges. This means that more of the current is flowing through a smaller cross-sectional area of the conductor, leading to higher resistance and increased power losses.

What are the practical implications of skin effect in AC power transmission?

Skin effect can lead to increased power losses and inefficiencies in AC power transmission systems, especially at higher frequencies. To mitigate these effects, engineers may use specially designed conductors or hollow conductors to reduce skin effect and improve the overall efficiency of the system.

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