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

[Charlie_V]

I think what Fritz meant is that a coil with an air core can be more efficient due to the fact that there is not a ferromagnetic core.  Most or all magnetic metals have a hysteresis loop and maintain a small amount of the field after the coil collapses (when the current is zero).  When the current starts to flow in the opposite direction (assuming AC here) a small amount of the energy goes into reversing the direction of the flux.  Just the alignment of the dipoles back and forth produces heat and is considered a loss (look up Magnetocaloric effect). 

There are also eddy currents.  Air cores do not have any of these problems and therefore are less lossy.  However, flux in the air core is not concentrated and this means they are not very good for motors, generators, etc.  You'll find air cores in places where sharp resonant peaks are needed (like radio). 

I've often wondered how good having a liquid oxygen core would be.  It shouldn't suffer from eddy currents or have a hysteresis loop yet should concentrate the flux nicely.  Also, I wonder if you could see a difference with just pressurized oxygen.

[nul-points]

hi Observer

interesting post on a new thread today by Butch LaFonte, about importance of OU inventions not using the wrong core material - struck a chord...

"Of those 30 [permanent magnet/electromagnet designs] I feel we got overunity indications from 3 maybe 4. We put loads on the generators and got no indication of increase in load on the drive motor. We had limited funding and we used solid mild steel for core material. If we had been able to use laminated electrical steel like the type used in transformers we would have seen a very dramatic difference in results."

"We were working with a permeability of 300 when electrical steel would have had as high as 5000. I'm still amazed we got any power at all using the mild steel with the low permeability and problem of eddy current losses due to the steel not being laminated and having high electrical conductivity as compared to silicon electrical steel"
...
"I have attached links that list the permeability of different materials and other useful information on the role of permeability of core material. Eddy current losses are very important also when choosing a material. Our mild steel would get to hot to touch and we had to stop the test runs due to this eddy current induced heat."
...
"Interesting note: Ultra high permeability materials The material with the highest magnetic permeability is Metglas Magnetic Alloy 2714A (Cobalt-based) [7] with a high frequency annealed permeability of 1,000,000 (Maximum DC Permeability (?)). Hydrogen annealed (pure iron - N5 grade) can have a permeability of 160,000 (?) but is very expensive.
Thanks,
Butch laFonte"

almost looks like Butch has been validating your hypothesis for you! 

all the best
sandy

[The Observer]

Sandy,

       Thank you for your references , I will most definitely explore them.

  A few cool guys I have found out about are John Keely who predicted E = M 25 years before Einstien.
    Another is Oliver Heaviside who coined many words used in electronics today.

You said,

        "i have noticed in my experiment is that i can make significant improvement to the charge transfer efficiency by piling additional ferrite material around my inductor"

I am not surprised, however my interpretation of adding ferrite material around the inductor has nothing to do with efficiency.
I believe that, as I have been saying, ferromagnetic materials ADD energy to the dynamic.
 
      That is, there is always energy in the ferromagnetic materials... magnetic dipoles which get their energy from whatever keeps the electrons moving.
      When all are lined up in different directions, it APPEARS as if there is no energy in that piece of iron.
      However, when they all line up ( or the majority of them ) they ADD ( I really mean it...) ADD up to enhance or ADD to the magnetic field of the coil.

This is what I am so damned concerned about.  ;o)~

Peace,
 
           The Observer


     

[otto]

Hello all,

@Observer

I will be short:

Im working on the TPU.

In the first time we all used coils without a core. With more or less success I lighted a bulb. Then i got a tip to use a core. As I had only cores from TV yokes I used them. The core is an iron powder core.

Results are expected: a 100W bulb is lighted without any problems. OK, with a high current but anyway lighted. When I used the same coils without a core I had almost no light. I see that my little TPU is very dangerous.

I hope I dont have to say what my next step is because its obvious.

I have to say that your posts are very good and please continue with them. I see you know exactly what youre wrighting because I see it in my little 4" TPU.

Otto

[The Observer]

Hey Charlie,

Hysteresis loop... yes
   Although some materials have a shape that looks like an S.
        This means that the remnant magnetic field is virtually nil.

Concentration less in air core...I think this is confusing to say and perhaps incorrect terminology.

A straight wire produces an electromagnetic field (with current)
   When you coil the wire... THIS is where concentration takes place.
     It's from coiling the wire and pushing the electromagnetic field of the wire (with current) into the center axis
       of the coil..

                                                B = ( μ0 * N  * i ) / l

         where μ0 is the permeability of free space, N the number of turns, i the current and l the length of the coil. *

The Magnetic field is proportional to the number of turns.

Now, a coil with a core.

                                              B = (μ0 * μr * N * i) / l

            where μr is the relative permeability of the material within the solenoid.

Do you see the difference?

    The difference is  μr   which is the MAGNETIC PERMEABILITY of the core.

This number is very near 1 for almost every element in the known universe!

  Then there are the rare few that have a number exceeding 1000 if not 1,000,000.

NOTE... there is no mention in these formulas about needing extra current to produce a greater field when a     
             core is used.  The only thing that it depends on is the magnetic permeability of the core !

Now if really want to talk about concentration, this occurs in greater magnitude as the coil's diameter gets smaller.
   So then Flux Density is in inverse relation to the area.
     That is... as the coil's area gets smaller... the flux gets greater... more is being squished in the center.

So, I hope you can see where I say the Core ADDS to the field and actually Concentrates nothing.

Oxygen as the core... interesting.
  Does Liquid Oxygen exhibit  ferromagnetic qualities?

Have a great day and thank you for your participation in this thread.

The Observer