Cool! Learn something new every day!
You say it stiffens the lines... is that due to electromagnetism?

 

Cool! Learn something new every day!
You say it stiffens the lines... is that due to electromagnetism?

I thought they were using double lines for reliability issues, and also because a wire of the proper gauge would be impractically thick and heavy...

 

Skin effect. 9 mm conductive layer for copper, 11 mm for aluminum (@ 60 Hz.).
Reference: http://en.wikipedia.org/wiki/Skin_effect

 

Skin effect. 9 mm conductive layer for copper, 11 mm for aluminum (@ 60 Hz.).
Reference: http://en.wikipedia.org/wiki/Skin_effect

Fascinating article, I found the Litz wire rather interesting too.
So that would mean that the maximum practical cooper wire gauge working @ 60 Hz would have a diameter of 18mm, right? How about making a hollow wire with a 9mm wall thickness, would that work as well?

 

I believe it would work. The principle of skin effect is that the core might as well not be there because it is not contributing to the job.

 

Fascinating article, I found the Litz wire rather interesting too.
So that would mean that the maximum practical cooper wire gauge working @ 60 Hz would have a diameter of 18mm, right? How about making a hollow wire with a 9mm wall thickness, would that work as well?

Cables are designed with this in mind -- the core is there primarily for strength without much, if any, concern given to conductivity.

 

Cables are designed with this in mind -- the core is there primarily for strength without much, if any, concern given to conductivity.

So now I wonder, are there cables whose core is of a different and cheaper material than its skin?

 

So now I wonder, are there cables whose core is of a different and cheaper material than its skin?

There are cables that have no core. I saw a picture of the feed line to a 50kW AM radio transmitter antenna and it looked like a big copper dryer vent hose. I'm guessing it was a foot or so in diameter and very thin walled. I don't know if that style is common for such applications or not.

 

There are cables that have no core. I saw a picture of the feed line to a 50kW AM radio transmitter antenna and it looked like a big copper dryer vent hose. I'm guessing it was a foot or so in diameter and very thin walled. I don't know if that style is common for such applications or not.

Now that you mention it, I recall that cooper tubing is used in induction heating applications, which usually run at high frequencies. And this is also taken advantage of by pumping liquid coolant through them.

 

So now I wonder, are there cables whose core is of a different and cheaper material than its skin?

Yes, although the wire I saw was probably more for marketing reasons than any practical application. There was a HiFi shop that had copper core, silver outer cable for speaker connections... almost the thickness of my little finger per "core"... it was also some incredibly crazy price per metre.

 

Yes, although the wire I saw was probably more for marketing reasons than any practical application. There was a HiFi shop that had copper core, silver outer cable for speaker connections... almost the thickness of my little finger per "core"... it was also some incredibly crazy price per metre.

I'd like to have a sample of one of those cables, connect them to my amp and speakers, and test them with an oscilloscope... see if the frequency response is noticeable

 

I'd like to have a sample of one of those cables, connect them to my amp and speakers, and test them with an oscilloscope... see if the frequency response is noticeable

I can almost guarantee that the difference in response will be hardly noticeable -- it might me measurable, but it is very unlikely that any human would be able to really tell the difference. There have been a number of controlled studies and the audiophiles have not fared well in any that I am aware of.

But because audiophiles believe that they are so sophisticated that they can tell the difference, they are easy marks for scams. Basically, someone tells them that their latest and greatest wowium-plated cables at $100/ft are the newest, hottest, best thing around and they will buy them and convince themselves that they are, indeed, far superior and worth every penny.

 

I can almost guarantee that the difference in response will be hardly noticeable -- it might me measurable, but it is very unlikely that any human would be able to really tell the difference. There have been a number of controlled studies and the audiophiles have not fared well in any that I am aware of.

But because audiophiles believe that they are so sophisticated that they can tell the difference, they are easy marks for scams. Basically, someone tells them that their latest and greatest wowium-plated cables at $100/ft are the newest, hottest, best thing around and they will buy them and convince themselves that they are, indeed, far superior and worth every penny.

And if this were Star Trek, they'd buy duranium alloy speakers...

 

profbuxon.....that is not my concept....that is electric law.

If the question is...do you need a completed circuit for charge flow...then the answer is no.

An antenna for example.

Now the transmission line is designed to deliver power.......of course to do that we need a completed circuit for the transmission line to work properly.

Do you believe that there is an alternating voltage on your un-connected wall receptacle?

Or do you believe the alternating voltage only appears if you connect a load?

The charge accumulation is happening twice every cycle.....one positive and one negative.

Every un-connected circuit in your house has charge flow.

 

So what is the current flow in an unconnected wall receptacle? 1A? 1mA? What?

 

SWER is single wire, the return path is earth ground.

http://en.wikipedia.org/wiki/Single-wire_earth_return

saves money, only one wire needed on the pole.

 

Every un-connected circuit in your house has charge flow.

Would you please elaborate?

 

A conductor has free electrons. If the conductor is free of external fields, the free electrons will be spread evenly on the surface. The number of free electrons is small compared to the un-free surface electrons.

Most surface electrons are not free.

These free electrons do not form a film like water......it's more like a equidistant grid of marbles.

This is because of charge repulsion.

Then why in the hell are they all on the surface?

This is because of charge repulsion also.

On the surface....the free electron can shine half of it's field out into space with no kick back.

Only a surface particle can do that.

Plus....if there is an internal disturbance, only half of it's field is bothered by the internal fields.

The surface is the calmest, safest place for them..........for the time being.

On a clean(neutral, no external fields) conductor....this grid is wide and sparse. Neutral charge.

The grid wraps around the conductor.

One grid line is related to amplitude, the other is related to phase. The grid lines are square and equidistant at neutral.

As charge moves back and forth on the conductor, this grid of electrons rotate as they move back and forth. The electric friction between the non free surface electrons and the rotating grid is the impedance of the conductor.

The free electrons follow the phase grid line. The angle of this grid line(to the longitude of the conductor) ....sets the rotation rate of the grid around the conductor.
This grid angle is usually set by the power source. This grid angle can be maintained and/or modified with reactance.

This distance between the amplitude grid lines determines charge amplitude. This is also usually set by the power source. This grid distance is modified with resistance and reactance. Amplitude grid lines that are close together have large charge. Grid lines that are wider have less charge. The polarity of the charge depends on the longitudinal direction of the grid.

These two grid lines act like springs, contracting and expanding longitudinally around the conductor.
Remember....there are millions of free electrons, on a grid.

We can have contraction and expansion at different areas on the conductor at the same time.
It depends on phase, length, external fields,etc..

These two grids can act as one or in harmony(frequency and/or phase related).

This isolated neutral grid pattern can be distorted with an external field.

When you shine an negative electric field on one end of the conductor......some electrons will be pushed to the far end .....because of repulsion. This is charge separation.
The number of electrons that stack up at the far end...depends on the strength of the field. This leaves a positive charge on the near end.

The conductor as a whole is still neutral...... but it is polarized. It is shelf charged. But no net charge.

The same thing happens on the output plate of an open capacitor.

The output plate is polarized and charged. Polarization charge, not current charge.

Now when we connect the conductor to the source, but keep the far end open.....things change a little.

Now the charge source provides the polarization. Plus the source can donate and except electrons to the conductor.

There is no separation of charge on the conductor(unless conductor is very long). The conductor as a whole has either a surplus or a deficit of charge(unless conductor is very long). The polarization is much stronger now. You can pick it up with a pocket sensor now.

The voltage of the source and the surface area of the conductor(plus wire characteristics), should determine the polarization current. If you can't measure it at the breaker box......try a longer circuit.

On second thought, don't try this with line voltage. Use a transformer....and use 12 AC, with a long conductor.

On second, second thought, don't use 12 AC. Don't try and measure the current.

Assemble an audio generator, audio amp, baking dish, speaker and ferrofluid(printer toner and vegetable oil).
60 Hz. is too fast for the fluid. Try 1 Hz. and change out speaker for appropriate resistor. Dip speaker(resistor)wire in fluid in baking dish. Bend and adjust wire to keep on surface of fluid. Adjust amplifier amplitude for to see rotating grid action.
It will not be the same as I explained. This is because the ferrofluid is reacting to the magnetic field of the grid, not the electric field. But you should see a rotating, back and forth movement. Because of low frequency and short wire length, there will not be much rotation. Try increasing frequency to spot twist before fluid falls apart.
Also try wire in vertical position in fluid. The fluid should spiral up and down the conductor with polarity change.

The polarization current(disconnect the resistor) will be very small compared to conduction current.

But if you make the conductor long enough........it will take all of the source output just to polarize it.

I am sorry if my rotating grid is confusing. The charge separation and the polarization should be clear.

Ferrofluid videos will show you some of what I am trying to explain.

 

It didn't give me a giggle... it gave the willies... I'm afraid of heights... and I'm afraid of high voltages... and I'm afraid of high voltages on high heights...

A little off-topic, but speaking of high heights...

 

And in the spirit of this thread, check this linked-in vid about workers doing their thing on tower power cables:

https://www.linkedin.com/posts/cels...ssas-vidas-activity-6703311914031706113-SH9x/