Magnetic Permeability ... I can't find anyone talking about this !!!!!

[The Observer]

Sudo,

You seem to have failed to examine the video where a Scandinavian Dude tests a coil with and without an iron core.

                                     http://www.youtube.com/watch?v=7tIaT_EZbMk

The rise time to max current is faster with the iron core.
                                                                                                        Which is completely opposite your theory.

Let's be clear...

                          You are defending a Conservation of Energy Theory based on Macro Mechanics..
                           Ferromagnetics is WAY more complicated than you acknowledge.
                           There are Quantum Forces acting in very unNewtonian ways..

                          Also, I am talking about ferros displaying
                          LOW MAGNETIC COERCIVITY (check Diagram below)
                          with a very thin Hysteresis Loop.

                          These dipoles spin easily and effortlessly to align...
                                                                                                     Anisotropic Energy to thank...
                                                                                                                                              otherwise you would probably be right !
                           
What you are basically saying is that when a magnet encounters a nail...
there is initially resistance before the attraction.
                                                                                                I hope you agree that is Nonsense.

I ask your definition of Magnetic Coercivity and Anisotropic Energy.
                                                                                                Extra Credit...A Ferromagnetic Hysteresis Loop.

Regards,
               The Observer

[Sudonym]

I am not forgetting anything, the test done by that man was not imperical, nor was it testing what you are trying to straighten in your head.

Instead of citing a poorly done video with equipment never intended to measure what you are looking for, why not try the tests for yourself, it has nothing to do with the attraction of a magnet. It has only to do with how quickly the inductor reaches its maximum current, and the energy contained within the inductor at that point.

Inudctive rise time is inductance / resistance. As resistance increases the current ceiling lowers meaning that the coil reaches "saturation" for that voltage more quickly. It also means that the inductor with all of its "electrical inertia" will come to a halt faster, meaning its inductive discharge time gets faster too. But in all cases increasing inductance causes an increase in inductive rise time. Grab an OSCOPE, Grab a signal generator, or 555 timer, or any current chopping device and test for yourself.

Question....if you make an LC tank circuit, and increase either L or C what happens? the frequency decreases...This is for the very same reasons as I have described prior. say we increase inductance through adding one of two cores, one core has low coercivity, one high, what happens??? The frequency of resonance is equal for both cores, but because of the differing histerisis loops, one will dissipate more energy. The tank circuit Q values will be different but the resonant points will be the same, meaning that inductive rise time has increased in both cases to the same degree.

Now like you said lets be clear....

I am not defending conservation of energy, I am defending the mechanics of inductors. I know personally how complicated ferromagnetics is, as it is my career.

Newtonian mechanics is known to be flawed, I did not defend it....

Also, I have never once claimed that there is a resistance before attraction. I do not know where you heard me claim this, but if you want me to argue it...ok, its called inertia, the nail has mass, and thus takes energy to move....an object in motion will stay in motion and an object at rest will stay at rest until acted upon by an outside source. There is always an innate resistance to motion or change in motion, relative or not, INCLUDING the current in inductor.

I have explained this several times, it is flawless, I have never seen it fail, if you want to prove me wrong, I will gladly accept you showing me otherwise, with a video of your own, proving that adding inductance decreases rise time. In the mean time I will make just such a video showing my point, using met-glass nano crystalline material, best on the market. That will be my last post on the subject, people can read your claims, my claims, and decide for themselves.

I dont think I have to defend my OU beliefs here, and wont be dragged into such an argument, but I will call out bullshit when I see it, because people are hear to learn fact, and most here would be upset if they were misinformed.

I also dont think it is time to start discussing histerisis loops and such concepts when the uber simple concepts have been missed!!!

[The Observer]

Sudo,

I appreciate your time on this.

Let me explain an important difference between Newtonian Magnets and Quantum Magnets.

            If you take 2 compasses and put them next to each other, or nearby, they skew and try to line up N to S.
            If you take 2 ferro dipoles and put them next to each other... they align N to N.. pointing in the same direction..
                     The energy that overcomes magnetic force and makes them align when they "shouldn't" is called Anisotropic Energy.

This energy, combined with the natural magnetic energy of ferros, are what can be tapped into.

Basically... a common speaker uses these energies.
       If you build a speaker without Ferros it takes ORDERS OF MAGNITUDE more energy to run the same volume output.
                Get it?
                 Ferro System Energy - Coil System Energy = Energy Contributed by Ferros

Understanding Coercivity and Hysteresis is imperative to understanding what energy is needed to saturate the core.
          The very thing we are discussing.
              - A Magnet takes ALOT of Energy to turn the dipoles.
              - Iron takes a little energy to turn the dipoles.
                                         
I think the fellows at the National High Magnetic Field Lab at Florida State are probably right.
                                          --------------------------------------------------------

             http://www.magnet.fsu.edu/education/tutorials/magnetacademy/magnets/page4.html

When you put the iron alloy core into a magnetic field
                      all the atoms in the iron align with it and, in so doing,
                               boost the magnet's field strength significantly,
                                              yet without using more electricity!

If it took soooo much more energy to turn the dipoles... don't you think they would mention it

I welcome your experiment, and eagerly anticipate your results.
                                                 If you can show me a ---- 1 second vs. 1 hour rise time ----- (low C core), you got me.
                                                 Good Luck !

Regards,
               The Observer

[Sudonym]

First and foremost...thanks for keeping things civil!

now on to the show....

This video shows the voltage across a pick up coil giving us a peak at the inductive rise of the inductor under test.

http://www.youtube.com/watch?v=3bi3bj9asyY

Because we are using an oscilloscope, we are taking a look at the voltage across the inductor. We can see that voltage is at its peak when the signal generator first turns on giving us a a steep almost vertical component to our viewed wave form. Then as the inductors amperage steadily increases durring its 5 time constant period, the voltage drops in the expected way. As it levels off, the signal generator reverses polarity and we get a mirror image on our trace.

The the time it takes for the inductor to go from its highest peak, back down to zero, is 5 time constants.

If we have no core, or in this case only half of a core, we have the steep vertical component, followed by a quick fall to zero, this indicates that all 5 time constants are squeezed into a very small time frame. As we add ferromagnetic material into the center, the time it takes to fall to zero increases, which  is literally equivalent to saying...as we add ferromagnetic material into the inductor, the time it takes the inductor to reach maximum current increases. In both cases maximum current is the same, the only difference is how long it takes to get there, and how much energy it holds when its all done (see previous mathematical proof).

This is ONE proof, that addition of ferromagnetic material increases the inductive time constants, or in other words, makes it take longer to reach its "current ceiling". But as pointed out earlier, this equates to more total energy stored within the inductor, so it is a trade off. More energy is stored, but it takes longer to get there. As I showed earlier in my mathematical proof, this equates to nothing gained, nothing lost.

Another proof is to do the same test with an LC circuit. Measure the resonant frequency of the LC when the inductor is an air core. Add a core, and watch as the resonant frequency drops considerably, because we have added to the time constant factor of the coil. Remember frequency will drop because it is an inverse function of time meaning that as the cycles take longer and longer the frequency gets lower and lower.

Here is a good website I found after the fact, which will show the same results I showed in the video with explanations as well.

http://webpages.ursinus.edu/lriley/courses/p112/labs/node9.html

here is a good quote from it that states what I just said in different words.....

The moment the switch in the circuit shown in Figure 20 is closed, there is no current flowing, and the voltage across the inductor is the same as the emf of the voltage source. The current immediately starts to increase from zero, changing rapidly at first, and leveling off as it reaches its steady-state value. The potential difference across the inductor decays exponentially with the rate of change of the current

I hope this clears things up a bit for the curious mind. Keep in the back of your head though that this is standard inductor behavior and applies to standard coils and standard cores, this does not apply to anything "exotic"

[The Observer]

Sudo,

Great Video !

It's getting late here, so I think I'll call er a day..

Thank you,
                  The Observer