The Skin Game

[sully]

Next, put them closer together..notice the zero point in the wire continues to move away from the opposite conductor.

Also, notice that the exterior tails are reducing in strength..that is because the external field is being cancelled as the conductors get closer together, while the peak field in the middle rises.

 

[sully]

This is the two placed side by side..note the between field has become linear.

But, look at the external field tails...boy, are they getting small..that is of course consistent with the lowering of external inductance felt by two wires, that log(D/d) term of the inductance equation..

That color bar on the right is the start of my ranging scale...pay no attention to that..

 

[sully]

Here's two like current conductors..notice the field in the middle goes to zero...that is because the field lines here cancel at the center of the wire spacing.

Also note, the zero point of the flux in the wires is being pulled towards the other conductor..

 

[sully]

and last, here are like conductors, closer still. The zero inside is still pulling to the other..and, the external tails have gotten bigger.

Gotta think about that..Hmmmm...the energy stored is 1/2 L I^2. Hmmm...if each wire has 2 amps, each has 2L joules stored energy. But, 4 amps in one would be 8L joules..

It would seem that using multiple spaced conductors to transport current results in lower inductive storage...

Gotta think about that one..

Cheers, John

 

[sully]

Credit where credit due..

In post #157, I attached a pic of the bessel vs exponential solution for skin depth...but didn't remember the source..

It was from Art Ludwig's website......thanks, Bruce..

Cheers, John

 

[spinch]

Around 3000 years ago the Babylonians believed currents in a conductor were caused by little elephants travelling in it. And Red Indians saw horses under steam locomotives pulling their wagons in a train of wags. Our professor remarked that by Fleming's Left Hand Rule electrons travel in a spiral when in motion. The moonshine that skin effect in wires is important at audio frequencies is a result which sells cables - and the popular press spreads such legends much farther.. misinformation sells, not the truth.

 

[jneutron]

Is there a particular reason a post I started 17 years ago suddenly is added to? Other than the fact that a skin effect thread was locked?

Jn (formerly known as sully)
Ps... those sims were Visual Basic 5 on a 486 running 100 MHz. A speed demon in the day.
Pps. Electrons in a vacuum will travel straight unless they are in a magnetic field. Then they will curve. If they are at a non 90 degree angle to the field lines they will indeed spiral.