magnetizing force


by samjesse
Tags: force, magnetizing
samjesse
samjesse is offline
#1
Feb19-10, 06:13 AM
P: 10
Hi

How does magnetizing force of a permanent magnet relate to magnetizing of steal rods of different sizes?

i.e. if I bring a permanent magnet and a piece of steal of the same sizes, put them together, the steal piece becomes magnetized.
what if I bring a much much larger piece of steal for the same size permanent magnet. how much magnetizing force will be in the tip of that big one?

is there a formula which takes size in account?

thx
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0xDEADBEEF
0xDEADBEEF is offline
#2
Feb20-10, 11:37 AM
P: 824
It is complicated and all formulas take size into account. The attractive effect of magnets is not straight forward. At least I don't know any better way to calculate forces than to calculate the whole magnetic field. Maybe you will find some rule of thumb in an engineering book.
Bob S
Bob S is offline
#3
Feb20-10, 01:51 PM
P: 4,664
For steel, you probably will need H = ~1000 amp-turns per meter. See

http://www.physicsforums.com/attachm...3&d=1264564310

For permanent magnet materials (e.g., neodymium), see Fig. 2 on page 7 of

http://www.oersted.com/magnetizing.PDF

You will probably need over 800,000 to 3 million amp-turns per meter. The can be done using current pulses.

Bob S

added attachment for magnetizing neodymium magnets. Looks like 3 MA/m (3 million amps per meter) are required.
See
Attached Thumbnails
Magnetization_neo_Hirst.jpg  

threadmark
threadmark is offline
#4
Feb23-10, 06:01 AM
P: 122

magnetizing force


A magnet works by adding electrons to the atom to create an unstable molecular structure in a iron molecule witch creates action at a distance. The process of energising the atom in the iron molecule to give an uneven amount of electron, creates fields and poles to keep a stable balance between protons and electron. The magnet attracts more protons to even out the instability.

Saying this, it depends on the excitement of the electrons in the iron molecule witch will affect the energy transferred. but you can only energize a molecule so much until it explodes.
Bob S
Bob S is offline
#5
Feb23-10, 02:43 PM
P: 4,664
Quote Quote by threadmark View Post
A magnet works by adding electrons to the atom to create an unstable molecular structure in a iron molecule witch creates action at a distance. The process of energising the atom in the iron molecule to give an uneven amount of electron, creates fields and poles to keep a stable balance between protons and electron. The magnet attracts more protons to even out the instability.
If I build a magnet that can pull all the protons out of water, will I have only oxygen left?

Bob S
samjesse
samjesse is offline
#6
Feb24-10, 03:50 PM
P: 10
In an inductance curve of a core where the Magnetizing Force in ampere-turns in the horizontal axis and [tex]A_L{}[/tex]-value = [tex]\mu[/tex] * H/N[tex]^{2}[/tex] in the vertical axis.
What exactly does the value of vertical axis mean?
and what does [tex]A_L{}[/tex]-value stand for?

Many thanks
luke1970
luke1970 is offline
#7
Feb24-10, 06:32 PM
P: 3
If a magnet powerful enough to pull the protons from water, then it would also pull the proton from oxygen not just the hydrogen. Maybe this would cause a breaqkdown of the basic atomic structure of the owygen also?


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