Is there any reference about how long magnetic remanence lasts, or is it permanent?
Quote from: rukiddingme on April 12, 2010, 04:27:21 AM
Is there any reference about how long magnetic remanence lasts, or is it permanent?
Try to google the issue, and see what you find. Usually most magnets are lasting for very long time, but temperature, exposure of other stronger magnets, and how you store them is important factors.
Vidar
Quote from: Low-Q on April 12, 2010, 08:54:32 AM
Try to google the issue, and see what you find. Usually most magnets are lasting for very long time, but temperature, exposure of other stronger magnets, and how you store them is important factors.
Vidar
That's not exactly what I am trying to figure out.
There are actually two aspects to the question.
1.) If you have an electromagnet and you pulse the coil, the core becomes magnetized. A little of the magnitism is retained by the core, but most of it dissipates. How long does it take for most of the field to dissipate?
2.) If you pass a magnet past a piece of metal, the piece of metal becomes magnitized. Some of the magnitism is retained by the metal, but most of it dissipates. How long does it take for most of the field to dissipate?
Here's the wiki article about remanence: http://en.wikipedia.org/wiki/Remanence
Remanence is the magnetization left behind in a medium after an external magnetic field is removed. It is denoted in equations as Mr. In engineering applications it is often assumed that the magnetization M is synonymous with the residual flux density B (they differ by a factor of µ0, BR = µ0M) hence the remanence is frequently denoted as BR (see the image). Only substances that can be magnetized, ferromagnetic and ferrimagnetic materials such as iron, have remanence.
To the right is an image of the hysteresis loop. I can't figure out where the time is shown.
Is there any reference that can give an approximate time frame for this? Are we talking a millisecond, ten milliseconds, a hundred milliseconds, five hundred milliseconds, a second?
I realize that it depends on the material. If anyone could give a guess how long it takes for the field to dissipate for cold rolled steel, it would be greatly appreciated.
Thanks in advance.
Quote from: rukiddingme on April 12, 2010, 11:23:07 AM
That's not exactly what I am trying to figure out.
There are actually two aspects to the question.
1.) If you have an electromagnet and you pulse the coil, the core becomes magnetized. A little of the magnitism is retained by the core, but most of it dissipates. A does it take for most of the field to dissipate?
2.) If you pass a magnet past a piece of metal, the piece of metal becomes magnitized. Some of the magnitism is retained by the metal, but most of it dissipates. How long does it take for most of the field to dissipate?
Here's the wiki article about remanence: http://en.wikipedia.org/wiki/Remanence
Remanence is the magnetization left behind in a medium after an external magnetic field is removed. It is denoted in equations as Mr. In engineering applications it is often assumed that the magnetization M is synonymous with the residual flux density B (they differ by a factor of µ0, BR = µ0M) hence the remanence is frequently denoted as BR (see the image). Only substances that can be magnetized, ferromagnetic and ferrimagnetic materials such as iron, have remanence.
To the right is an image of the hysteresis loop. I can't figure out where the time is shown.
Is there any reference that can give an approximate time frame for this? Are we talking a millisecond, ten milliseconds, a hundred milliseconds, five hundred milliseconds, a second?
I realize that it depends on the material. If anyone could give a guess how long it takes for the field to dissipate for cold rolled steel, it would be greatly appreciated.
A in A.
Now I see ;D Sorry! Well the answer is still how the metal is treated with temperature, other magnetic materials etc. To cancel the magnetism, you can use a coil with a high freqyency and gradually decrease the amplitude till zero. Then the metal should be neutral again. But at room temperature with no other treatments, I really don't know for how long it will last. I have however magnetized screwdrivers, and the magnetism is considerably weaken after a week or so.
Vidar
Quote from: Low-Q on April 12, 2010, 11:59:42 AM
Now I see ;D Sorry! Well the answer is still how the metal is treated with temperature, other magnetic materials etc. To cancel the magnetism, you can use a coil with a high frequency and gradually decrease the amplitude till zero. Then the metal should be neutral again. But is room temperature with no other treatments, I really don't know for how long it will last. I have however magnetized screwdrivers, and the magnetism is considerably weaken after a week or so.
Vidar
I think you are thinking about retentivity:
http://en.wikipedia.org/wiki/Retentivity
The retentivity of a material is its capacity to remain magnetized after the external magnetizing field has ceased to exist.
I was under the impression that when you pulse an electromagnet, the core becomes magnetized. When the pulse ends, there is a period of time that it takes for the magnetic field to dissipate. This is the number I am looking for. How long a piece of steel takes to lose its magnetism after being pulsed.
Maybe I have it wrong, maybe a steel core loses it's magnetic field instantly, but that doesn't seem intuitive.
I'll keep researching this and if I can find the answer, I'll post it here. :)
RuKiddingMe,
You are starting to ask some very good questions !
Not many people here seem to care how Ferromagnetic Materials operate !
I started this thread a couple years ago...
http://www.overunity.com/index.php?board=10.0
called Magnetic Permeability ... I can't find anyone talking about this !!!!!
My guess is that if you read this thread ( I have not added to it to keep it short)
you will come away with alot of questions answered in your head.
As of yet.. I seem to be the only person who says WOW !
when a piece of iron Amplifies the magnetic field of a coil 5,000 times !
Hell.. Super Perma-ally Amplifies it 1,000,000 times !
You see..most think Ferromagnetic materials CONDUCT a magnetic field. (SO WRONG !!!)
When in fact, say, a piece of iron turns into a magnet in the presence of an outside field.
in other words... The randomly Pointed dipoles in the iron line up to form a 'magnet'.
There is no 'disapation' of the magnetic field of the iron after the coil is turned off.
Anisotropic Energy turns the the dipoles in the iron back to random directions
after external field turned off (Source of Bedini Pulse I believe,).
Anyways...I implore you to study this, so I have someone to talk about this with !
Have a great day.
The Observer
Quote from: The Observer on April 12, 2010, 02:18:44 PM
RuKiddingMe,
You are starting to ask some very good questions !
Not many people here seem to care how Ferromagnetic Materials operate !
I started this thread a couple years ago...
http://www.overunity.com/index.php?board=10.0
called Magnetic Permeability ... I can't find anyone talking about this !!!!!
My guess is that if you read this thread ( I have not added to it to keep it short)
you will come away with alot of questions answered in your head.
As of yet.. I seem to be the only person who says WOW !
when a piece of iron Amplifies the magnetic field of a coil 5,000 times !
Hell.. Super Perma-ally Amplifies it 1,000,000 times !
You see..most think Ferromagnetic materials CONDUCT a magnetic field. (SO WRONG !!!)
When in fact, say, a piece of iron turns into a magnet in the presence of an outside field.
in other words... The randomly Pointed dipoles in the iron line up to form a 'magnet'.
There is no 'disapation' of the magnetic field of the iron after the coil is turned off.
Anisotropic Energy turns the the dipoles in the iron back to random directions
after external field turned off (Source of Bedini Pulse I believe,).
Anyways...I implore you to study this, so I have someone to talk about this with !
Have a great day.
The Observer
Thanks for the response.
So it's your opinion that the magnetic field caused by a coil pulse or a passing magnet goes away instantly, as soon as the current or magnet is removed.
Kidman,
Well, there is Remanence.
Or.. A few of the dipoles stay in the direction they were oriented by the external magnetic field.
However this really doesn't exist in Modern Transformer Core Type 'metals'.
The hysterisis loop follows the same path down as up.
What should blow your mind is that a piece of iron magnifies the field of the coil by 5000 times !
With no extra electricity needed. (quote from the National Magnetic Lab in Florida)
Why? The iron's internal randomly oriented magnetic field lines up in the same direction.
The Observer
Quote from: The Observer on April 12, 2010, 08:59:17 PM
Kidman,
Well, there is Remanence.
Or.. A few of the dipoles stay in the direction they were oriented by the external magnetic field.
However this really doesn't exist in Modern Transformer Core Type 'metals'.
The hysterisis loop follows the same path down as up.
What should blow your mind is that a piece of iron magnifies the field of the coil by 5000 times !
With no extra electricity needed. (quote from the National Magnetic Lab in Florida)
Why? The iron's internal randomly oriented magnetic field lines up in the same direction.
The Observer
Observer, I also find that fascinating and saw your reference to that before. Since it magnifies the field of the coil so much in what ways do you think this might be useful? Can this be useful in some new way to generate energy at a high COP? I'm a bit lost on theory of magnetic fields but I assume others know this concept and I'd like to think there's a hidden energy egg in there somewhere. But it's not jumping out at me as far as how it may be 'real world' useful.
E2,
Cool Beans...
You need to read my thread on it.
http://www.overunity.com/index.php?board=10.0
Magnetic Permeability ... I can't find anyone talking about this !!!!!
When a person realizes that a piece of iron is a magnet that can be turned 'on and off' so to speak,
ideas can start to fly.
- a piston where there is no magnets just iron.. 1 iron inside a coil.
- a mechanical lever that lifts, then gravity pulls it down.
- Of course the Bedini Pulse is really from Anisotropic energy that turns the dipoles inward.
thus causing a fast change in magnetism.
in other words.. when current is suddenly turned of in the coil
the iron is at that very moment a magnet...
But it's internal energy (Anisotropic) pulls everything back to random...
I'm excited that someone wants to talk about this now.
Before.. all I got was Misinformation Agents.
BTW
...somehow that thread was looked at 7000 times
during a year and 1/2 period when it was buried deep in this site
... without 1 single reply !! hmmm
I wonder who was so interested in it?
The Observer
like ... ?
http://ferromagnetic-energy.com/core_of_the_physical_effect/
http://www.intalek.com/Index/Projects/Patents/DE3024814.pdf
Observer - So as to not sidetrack this thread I did post on your permeability thread - maybe that will get things going there again.
I try to stick to things I know something about!
If I don't I'll keep my mouth shut.
be
QuoteWhat should blow your mind is that a piece of iron magnifies the field of the coil by 5000 times !
With no extra electricity needed. (quote from the National Magnetic Lab in Florida)
Observer - great quote. Is this the secret to Stubblefield's earth battery?
Great topic.
Bob
Is iron's ability to magnify the power of a copper coil also something that might be considered with regard to reproducing Alfred Hubbard's coil generator?
There are a lot of variables that come in to play and the exacts need to be known to figure out what you are asking. Time life depends on the strength of the charge as well as the size charged. One life will not be as exact as another unless the variables are exactly the same.
I am not sure why you are asking this question but do keep in mind that any slight difference in a variable will have an affect on the over all life.