Need help finding magnets for experiment...
jim
diameter with no hole in the center. The thickness can be as much as 13 mm
25.4mm.
The strrength is not as important as the dimensions and that it be a solid
disc (no hole in center).
I have found neo magnets that are up to 8" in diameter, but their strength
will actually make it more difficult to perform the initial experiment.
If anyone knows where I may purchase ceramic desci magnets that are at least
120mm in diameter and up to 25.4mm in thickness, with no holes in them,
please let me know.
Thank you for your help.
(I have Googled, Ask'd, Yahoo'd, etc. - all to no avail. The magnets that I
have found generally top out at 76mm in diameter. If I have missed
something in these searches, I would appreciate someone pointing it out.)
jim
Cwatters
"jim" <j...@home.net> wrote in message
news:n8Uik.7784$US3....@bignews2.bellsouth.net...
Why not mount a lot of smaller magnets in "parallel" ?
hhc...@yahoo.com
Jim, out of simple curiousity, what is your objection to the magnets
having holes in the middle?
Harry C.
jim
"Cwatters" <colin.wat...@TurnersOakNOSPAM.plus.com> wrote in message
news:QYqdnfYPz70...@posted.plusnet...
The result would be many "hills" and "valleys" in the magnetic flux field.
That type of magnetic flux field is not desirable for this experiment.
Jerry
I suspect that you are asking the wrong question. I suspect that
your REAL question is, how can you create a close approximation
to a uniform magnetic field over an area of many square
centimeters.
The answer WON'T be by using a large monolithic hunk of ceramic.
Inevitable nonuniformities in manufacturing that arise during
the magetization step mean that the strength of field will vary
considerably between center and edge of the disc.
Instead, consider a large array of carefully matched magnets
faced off by pole pieces.
Why don't you share your actual requirements with us, rather
than trying to be so secretive about the experiment that you
intend to perform?
Jerry
jim
<hhc...@yahoo.com> wrote in message
news:afd184f0-ac13-42fc...@e39g2000hsf.googlegroups.com...
It alters the magetic flux field. I am looking for the same field as you
would "see" coming out of the end of a simple cylinder magnet.
jim
p.b...@by.co.uk
says...
>
> "Cwatters" <colin.wat...@TurnersOakNOSPAM.plus.com> wrote in message
> news:QYqdnfYPz70...@posted.plusnet...
> >
> > "jim" <j...@home.net> wrote in message
> > news:n8Uik.7784$US3....@bignews2.bellsouth.net...
> >>I need some help in locating ceramic disc magnets that measure 120mm in
> >> diameter with no hole in the center. The thickness can be as much as 13
> >> mm
> >> 25.4mm.
Probably a last resort or even off the wall but ...
I dont know if this is any help but I read somewhere last week about
a company that's produced a portable NMRI (battery powered no less) and
the photo I saw showed a round cylindrical device.
Being an MRI it must use magnets and (being so small they can't be
electro) since the shape is cylindrical it
just occurs to me they may have used just what you are asking for ...
If you contact them maybe they would be willing to connect you to their
source.
I think I saw it in Scientific American but I'm not too sure .. you may
have to google.
-peter-
Mike D
Most large diameter ceramic magnets were designed/tooled for
loudspeakers and holding cup assemblies. Both of those involve large
quantities and require a hole, so they drive the market.
One option is to use a magnet fabricator to grind a disc shape out of
a solid rectangular block. There are standard 1" x 4" x 6" magnet
blocks (oriented thru the 1" direction). It won't be cheap because
it's a fair amount of labor to do that.
The other alternative is to weaken the Neodymium magnets since you
moderate heat. You'll have to experiment to find the right
temperature. If you get them too hot and demagnetize them too much,
you'll have to remag to restore them.
Good luck.
Mike
PD
Mill a soft steel pole piece and affix a magnet or several magnets to
the back of that. The pole piece will spread and homogenize the field.
Why does it have to be a permanent magnet? Why aren't you considering
an air-core (or iron core) electromagnet?
PD
jim
Thanks Mike.
I think I am going to retool my experiment to use a small neo magnet (3"
in diameter) for testing.
I had hoped to use something larger simply because working with larger
objects is easier than trying to machine all of the smaller parts that I
will need.
But, you work with what you have handy I guess.
jim
jim
Didn't mean to sound so secretive....just didn't think it really
mattered. I'm just interested in how magnets behave in a monopolar
situation as opposed to the usual 2 poles that they are found in.
In particular, I wondered (not being big in physics) what would happen
if I mounted a small magnet on a horizontal arm in the center of a
larger disc magnet that kept the smaller magnet within the diameter of
the disc magnet and kept the smaller magnet close to the larger disc
magnet's surface while allowing horizontal movement and not allowing
vertical movement.
I actually wondered if the smaller magnet, turned slightly so that it's
opposing pole faced the surface of the disc magnet at an angle, would be
propelled around the arm in a circular motion due to the force created
between the opposing magnetic flux lines.
My tests are not very scientific and my tools are not exact in their
manufacture, but I have determined that it will not move at all unless
acted on by outside forces.
The magnetic force exerted by the face of the disc magnet against the
angled, same pole of the smaller magnet does produce a force. But, it
is not a force in the sense of wind acting on a windmill's propellers or
of water falling on the blades of a turbine or even photons hitting the
vanes of a radiometer.
It seems that magnetic force is a force, but is not a moving force (as
wind, photons or water droplets) which is needed to produce movement in
another object.
My interest was aroused when I watched some youtube videos of people
attempting to build motors using only permanent magnets for power.
I can see the attraction of such an idea, and how it deludes many into
thinking it is possible. Alas, it is not possible to build a motor
using only permanent magnets as the power source.
I knew that going in. And, although I suspected it, I had seen no
experiments that used a single disc magnet (as opposed to many
exotically arranged magnets) as the stator and I was curious as to
whether the opposing magnetic fields in such an arrangement would act as
a "high pressure" area and produce movement in the arm holding the
smaller magnet.
In my very unscientific testing it resulted in no movement of the
smaller magnet or the arm holding it.
I suspect it is because the magnet's flux field must compress the disc's
flux field lines in order to move in any direction. Therefore, there is
no "low pressure" area for the smaller magnet to move towards. The
"pressure" (or magnetic flux field) of the disc is the same all around.
Thus, there is no potential difference to take advantage of.
I had thought that the compression of the 2 opposing fields may result
in a higher pressure area that may move the arm holding the smaller
magnet forward. It did not.
I was just curious.
Now I know.
Thanks for your help!
jim
jim
> On Jul 27, 9:28 am, jim <j...@home.net> wrote:
>> I need some help in locating ceramic disc magnets that measure 120mm in
>> diameter with no hole in the center. The thickness can be as much as 13 mm
>> 25.4mm.
>>
>> The strrength is not as important as the dimensions and that it be a solid
>> disc (no hole in center).
>>
>> I have found neo magnets that are up to 8" in diameter, but their strength
>> will actually make it more difficult to perform the initial experiment.
>>
>> If anyone knows where I may purchase ceramic desci magnets that are at least
>> 120mm in diameter and up to 25.4mm in thickness, with no holes in them,
>> please let me know.
>>
>> Thank you for your help.
>>
>> (I have Googled, Ask'd, Yahoo'd, etc. - all to no avail. The magnets that I
>> have found generally top out at 76mm in diameter. If I have missed
>> something in these searches, I would appreciate someone pointing it out.)
>
> I suspect that you are asking the wrong question. I suspect that
> your REAL question is, how can you create a close approximation
> to a uniform magnetic field over an area of many square
> centimeters.
Not really. A ceramic disc's magnetic flux lines (assuming they eminate
from the ends and have only a single set of poles) are not uniform in
strength. There is a definite pattern to the magnetic field lines that
you can easily see when you do the old iron filings on paper over a bar
magnet made from a cylinder.
A uniform magnetic field may be fun to play with, but would not
approximate the magnetic flux line pattern found at the poles of ceramic
or neo disc magnets.
>
> The answer WON'T be by using a large monolithic hunk of ceramic.
> Inevitable nonuniformities in manufacturing that arise during
> the magetization step mean that the strength of field will vary
> considerably between center and edge of the disc.
Yes they will. I never asked for a uniform magnetic flux field for
testing.
> Instead, consider a large array of carefully matched magnets
> faced off by pole pieces.
>
> Why don't you share your actual requirements with us, rather
> than trying to be so secretive about the experiment that you
> intend to perform?
For 2 reasons... (1) If I am onto something, revealing what little I
know without a reliable means of reproducing the effect for the
scientific community would only serve to confuse the issue and start
debates that will waste time and not answer the questions that I can
answer with a few simple experiments. (2) If I am wrong, revealing the
goals, theories and suppositions of the experiment may make me look
foolish. Why do that when I can simply experiment, learn and grow in
wisdom without the public humiliation of trying an experiment that may
have flaws that are not obvious to me at this time.
I know of no better way to learn something than to do it for yourself.
Reading about things is only memorization. True learning comes from
doing.
IMHO, it is wise to say as little as possible when it comes to theory
and experimentation until such time as you have answers that can be
objectively proven via scientific experiments by others - independent of
your help.
Thanks for your posts.
jim
jim
Thanks Mike.
Cephalobu...@comcast.net
> Jerry wrote:
> I know of no better way to learn something than to do it for yourself.
Agreed!
> Reading about things is only memorization. True learning comes from
> doing.
>
> IMHO, it is wise to say as little as possible when it comes to theory
> and experimentation until such time as you have answers that can be
> objectively proven via scientific experiments by others - independent of
> your help.
>
> Thanks for your posts.
Regardless of the merits of your ideas, it's good that you've
chosen to post on sci.physics.research. Being moderated, posting
on this group automatically insulates you the screaming madhouse
that exists on the other groups to which you have crossposted.
Yours is just the sort of proposal that would attract undue
attention from, for example, "overunity" homopolar generator
fanatics
You seem to be a very honest (if somewhat naive) amateur
experimentalist. I can tell you in advance that no matter what
sorts of variations you add to your original experiment, you
won't succeed in achieving permanent motion. But as you say,
there is no better way of learning something than doing it
yourself, and you can get a lot of enjoyment even from "failed"
experiments.
So good luck, and remember to have fun!
Jerry
Cwatters
>> Why not mount a lot of smaller magnets in "parallel" ?
>
> The result would be many "hills" and "valleys" in the magnetic flux field.
> That type of magnetic flux field is not desirable for this experiment.
Square magnets?
How uniform does it need to be?
Cwatters
> Jerry wrote:
> Didn't mean to sound so secretive....just didn't think it really
> mattered. I'm just interested in how magnets behave in a monopolar
> situation as opposed to the usual 2 poles that they are found in.
Poles are allways found in pairs...at least so far...
http://en.wikipedia.org/wiki/Magnetic_monopole
http://physicsworld.com/cws/article/news/18338
Salmon Egg
A point on any rotating disk sees an electric field
E' = E + Em
E is the electric field present at that point in the absence of
rotation. Em is the electric field produced at the point by motion
through the magnetic field.
Em arises from motion through the magnetic field as described by special
relativity (SR). Equivalently, Em can be considered to arise from the
Lorentz force v x B. That is, this field can be considered to be a
physical law unto itself established by experiment. I would consider the
SR approach to be more fundamental.
If the Lorentz force is considered to be a physical law, I think that it
would be a basis for deriving SR.
In any case, line integrals of the inner product (E', ds) can be
calculated to describe behavior of the Faraday disk.
Bill
jim
The theory that I was looking to experiment with was one whereby
youtubers have tried to create motors utilizing permanent magnets as the
only source of power.
The mag-motor experiments that they tried always used separate magnets
to create the opposing magnetic fields.
Even if you were to suppress one side of the magnets' fields, you still
have a magnetic field that is being resisted by every opposing magnetic
field (a hill) as it passes by.
I simply wondered what would happen if you replaced their hills and
valleys with a uniform magnetic field (say a disc magnet's end field)
and then placed a magnet inside the uniform magnetic field, mounted on
an arm (which can only move horizontally in a circle above the disc
magnet) with the opposing field of the mounted magnet aimed at the
opposing field of the disc magnet at an angle.
My question was whether the two opposing fields would create sort of a
"high pressure" magnetic field and move the arm forward along a
circular, horizontal axis.
The answer was that there is no movement.
The reason is (my supposition here) that the force needed to compress
the magnetic flux lines of the opposing magnetic disc as the arm moved
forward cancel out the "high pressure" of the opposing magnetic flux
lines I had thought may do the "pushing".
The flaw in my model (and theirs) is that they (nor I) had taken into
account the fact that movement is always from an area of high pressure
to lower pressure (whether that be air or water or electrons or magnetic
fields).
In order for their magnetic motors to work, there must be and area of
high magnetic resistance and an area of lower magnetic resistance that
constantly moves (as the magnetic field in an electric motor moves) to
sustain movement.
Although I have seen some real "outside the box" thinking on the
subject, only one person has managed to lower the magnetic fields
opposing the movement of the motor to any degree whatsoever. And, his
experiment was not done in a way that may state emphatically that his
method works (his equipment was not done to exacting measurements and
those off placements of the parts may have accounted partially for the
run-time that he did achieve - but which was also short lived).
Until such time as somebody comes up with a way to mechanically turn a
permanent magnetic field on and off at will, this mag-motor device will
not function as desired.
It is also my opinion that no device can operate without some sort of
outside energy (whether that be solar, wind or even the use of
gravitational force).
The idea of a permanent magnetic motor is intriguing. And, while I say
that nothing is impossible, a working mag-motor will take a much more
complex design than is presently being attempted in the videos on youtube.
Thanks for your post!
jim
Dirk Bruere at NeoPax
> Cwatters wrote:
>> "jim" <j...@home.net> wrote in message
>> news:Llpjk.134$XT1...@bignews5.bellsouth.net...
>> >> Why not mount a lot of smaller magnets in "parallel" ?
>>> The result would be many "hills" and "valleys" in the magnetic flux
>>> field.
>>> That type of magnetic flux field is not desirable for this experiment.
>>
>> Square magnets?
>>
>> How uniform does it need to be?
>
> The theory that I was looking to experiment with was one whereby
> youtubers have tried to create motors utilizing permanent magnets as the
> only source of power.
If you're into Weird Science then check out Naudin's site.
http://jlnlabs.online.fr/
He actually does the experiments and hunts down the 'urban myths'. A
kind of Weird Science MythBuster.
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.onetribe.me.uk/wordpress/?cat=5 - Our podcasts on weird stuff