Skin Effect

[Malik2013]

someone please explain “Skin Effect”” with an example from real life electrical:::

[tarekibra88]

As the cable cross section(C.S) increases, the
density of current (A/mm²) decreases due to skin effect.

 

	Maximum AMPACITY	Current Density A/mm2
1 mm2	13 A	13
3* 150 mm2	350 A	2.3
3 * 300 mm2	570 A	1.9
3 * 400 mm2	680 A	1.7
3 * 630 mm2	880 A	1.4

the current passes in the outer layers  and decreases gradually to be zero in the
inner layers

[admin]

In DC,

            the current carriying conductor  allows current  to flow overall its area of cross section  (area of cross section completely used to flow of current or uniform current distribution)……

where as AC,

          allows current to flow only in its surface of cross section area (or non-uniform distribution)…

                  which is nothing but skin effect……

[ENOCK MULENGA]

Skin effect is the tendency of an alternating electric current (AC) to distribute itself within a conductor with the current density being largest near the surface of the conductor, decreasing at greater depths. The electric current flows mainly at the “skin” of the conductor, between the outer surface and a level called the skin depth. The skin effect causes the effective resistance of the conductor to increase at higher frequencies where the skin depth is smaller, thus reducing the effective cross-section of the conductor. The skin effect is due to opposing eddy currents induced by the changing magnetic field resulting from the alternating current. At 60 Hz in copper, the skin depth is about 8.5 mm. At high frequencies the skin depth becomes much smaller. Increased AC resistance due to the skin effect can be mitigated by using specially woven litz wire. Because the interior of a large conductor carries so little of the current, tubular conductors such as pipe can be used to save weight and cost.

[Author]

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