A 1mm diameter wire will have skin effect at 10khz. The resistance impact will be roughly 100 milliohm increase per 1000 feet.
The inductive impact will be a reduction of internal inductance to the tune of 2 to 5 nanohenries per foot.
Neither is very significant, and I suspect I could not measure it with current SOTA.
Skin effect is the redistribution of current density (not charge density) as a consequence of the conductivity of the metal and time rate of change of magnetic field trying to penetrate the metal. Eddy currents sum with the transport current to redistribute the effective current density.
It's just the current trying to follow the path of least impedance, nothing more, nothing less.
Jn
The inductive impact will be a reduction of internal inductance to the tune of 2 to 5 nanohenries per foot.
Neither is very significant, and I suspect I could not measure it with current SOTA.
Skin effect is the redistribution of current density (not charge density) as a consequence of the conductivity of the metal and time rate of change of magnetic field trying to penetrate the metal. Eddy currents sum with the transport current to redistribute the effective current density.
It's just the current trying to follow the path of least impedance, nothing more, nothing less.
Jn
So a picture of a power line shows skin effect?
??? Did you just make that up? Ever heard of 3 phase power lines? 1 phase per wire sometimes plus ground?
You can't hide IT follows you. There's no skin effect at audio frequencies, RG58 is not a transmission line at audio frequencies, it just keeps on going.
jneutron,
charge density refers to ionic charge, in common parlance: current. Ionic charge is not at all uniformly distributed within the conductor and it moves more easily in the surface layers.
It seems to me that you have not pondered this matter thoroughly enough and have long way to go.
charge density refers to ionic charge, in common parlance: current. Ionic charge is not at all uniformly distributed within the conductor and it moves more easily in the surface layers.
It seems to me that you have not pondered this matter thoroughly enough and have long way to go.
Scott,
I know. Saw somebody over at ASR say you can't parallel multiple coax to reduce the effective impedance. Sigh, just not worth engaging. What did someone say.... ankle biters.
I remember when I first entered the world of Internet forums... I really thought knowledge would progress fast, and that everybody would participate to grow what is known and learn what is unknown.
That was when I was young, stupid, and naive. I'm much older now.
Probably should tell the pulsed magnet guys that what they did cannot work, so might as well pull the multiple paralleled cables out..
Trying to design up a test to measure midband speaker impedance during low frequency excursion. The complexity of the problem is exhilarating. When I figure it out, have no idea who to collaborate with.
Jn
I know. Saw somebody over at ASR say you can't parallel multiple coax to reduce the effective impedance. Sigh, just not worth engaging. What did someone say.... ankle biters.
I remember when I first entered the world of Internet forums... I really thought knowledge would progress fast, and that everybody would participate to grow what is known and learn what is unknown.
That was when I was young, stupid, and naive. I'm much older now.
Probably should tell the pulsed magnet guys that what they did cannot work, so might as well pull the multiple paralleled cables out..
Trying to design up a test to measure midband speaker impedance during low frequency excursion. The complexity of the problem is exhilarating. When I figure it out, have no idea who to collaborate with.
Jn
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I assume you can provide some textbook references?
And yah, I rarely ponder this electrical stuff, I'm surprised my employer continues to pay me.
Jn
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No, read the caption. Note the three wires in this one "conductor" help avoid the limits of skin effect. (in one of the three phases)
It is really big "Litz" (in the US sense), without the braid. You get more skin for the same amount of metal.
People who do math may object that the increased heat dissipation is the more compelling reason for three wires per phase. Or that a district load grew over decades and it was better use of capital to install one wire in 1980, a second in 2003, and a third in 2016. (My street is wired 2/3 wYe, just waiting for the demand boom they expected in 1983.)
As indra1 said...
It's not skinning, it is voltage gradient in the surrounding air. With a megavolt conductor, say #12 AWG, the voltage gradient in the air next to the conductor is high enough to ionize the air. By going to larger diameter, the gradient is reduced.
The pic is an example of using multiple conductors to reduce the air gradient.
It has nothing to do with skin effect.
Jn
It's not skinning, it is voltage gradient in the surrounding air. With a megavolt conductor, say #12 AWG, the voltage gradient in the air next to the conductor is high enough to ionize the air. By going to larger diameter, the gradient is reduced.
The pic is an example of using multiple conductors to reduce the air gradient.
It has nothing to do with skin effect.
Jn
It seems to me that you have not pondered this matter thoroughly enough and have long way to go
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