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MONOPOLE Impersonator? HALBACH Array Fabricated (Flux Lines ADDED)

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Sulaiman

Sat Feb 24 2007, 08:08PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3141

I believe that this Halbach stuff is mostly hype because;

If you took a solid mass of NdFeB material
in the shape of a block for the first shown device
and in the shape of a disk with a hole for the second

Then magnetise the material forming the poles where required
the resulting field strength would be greater for the same mass of NdFeB material.

For a few amateur uses I can see the benefit of being able to assemble standard magnets in a useful way
BUT for example in the first case, a solid steel backing plate
would provide greater flux density, more concentrated poles, with half the mass of NdFeB material.

CM, Why use twice the mass of magnet material when a steel plate would be better?
(If eddy-currents are a concern use laminated steel)

Sat Feb 24 2007, 08:26PM

Banned on April 7, 2007
Registered Member #277 Joined: Fri Mar 03 2006, 10:15AM
Location: Florida
Posts: 157

Sulaiman:

You make a interesting point, but I'm just the messenger. I don't know why NASA and Department of Energy and others are dumping money into developing new technologies utilizing the Halbach array other than we can assume their scientists, engineers, physicists, believe it offers some characteristic not readily available or economical by other means. But if they could accomplish the same results by using less magnet and more steel, it would surely be cheaper. Assuming your approach delivers the desired result, it would be of interest to NASA and DOE since it would be considerably cheaper. If you have any interest in submitting your idea to NASA or the DOE, I can forward the start up information to you. There are three phases of R&D funding available to accepted applicants. Just let me know. CM

Hazmatt_(The Underdog)

Sat Feb 24 2007, 08:45PM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

This is just becoming more of "The Pot calling the Kettle Black"

Wasted energy thread, or harnessed energy thread, whatever, BUT This thread is just as Guilty of being Mistitled. NO MONOPOLES, SORRY!

So change it to the HALBACH-Mag Lev thread.
Monopoles are pure pseudo-science.

Sat Feb 24 2007, 08:49PM

Banned on April 7, 2007
Registered Member #277 Joined: Fri Mar 03 2006, 10:15AM
Location: Florida
Posts: 157

Sulaiman:

Here's some more info that is applicable to your question, although they don't specifically address your idea:

The Office of Science of the U.S. Department of Energy says "Previous research teams had rejected permanent magnets for maglev systems because designers believed the magnets would yield too little levitating force relative to their weight. Two developments resolved that problem. In the 1980s, the late Klaus Halbach, a physicist at Lawrence Berkeley National Laboratory, invented the Halbach array to focus accelerator particle beams. In this array, permanent magnets are configured so that the field intensity is concentrated below the array but canceled above it. Post says, "Our use of Klaus's array in Inductrack is a good example of basic research being put to practical use to help meet a national need." ... "The National Aeronautics and Space Administration (NASA) is also considering Inductrack technology for launching rockets." The entire article can be read here

Sat Feb 24 2007, 09:19PM

Banned on April 7, 2007
Registered Member #277 Joined: Fri Mar 03 2006, 10:15AM
Location: Florida
Posts: 157

Haz:

We've been encouraged not to use that word further due to goggle spider (if I understand correctly). I wish I could share your assurance that something doesn't exist. To be clear, I am not supporting the existence of one-pole magnets. History is a good teacher. There were some smart people (a minority at first) who predicted the possiblity of black holes while many bystanders simply dismissed it because they had not yet been discovered. Likewise, today there are some intelligent people, a minority for sure, that subscribe to the 'possibility' that 'one-pole' magnets might exist, but have yet to be discovered, as predicted by super-string theories.. if you believe in that sort of thing. (I'm not sure if super-string theory is considered a pseudo-science here or not, if there is a clear position on this, somebody let me know please). If super-string theory is dismissed, there also exists at least one Grand Unified Theory that predicts the possibility of 'one-pole' magnets, but that certainly does not mean they do exist. I believe the title of my thread is clear enough to the average reader and up. In response to your post, I selected the word "Impersonator" in order to clearly convey that the Halbach array behaves as if it is something... that it is not. The Halbach array appears to have only one pole to the human senses, (that is if you play around with it, placing it close to metalic objects or other magnets, etc) but we know that it has two poles. It's impersonating a one-pole magnet when examined only by the use of human senses. Under any type of scientific investigation, it can clearly be seen that it has two poles, but we know the reason it behaves as a one-pole magnet is because the 2nd pole is nearly cancelled out. I encourage folks to build one, they are very interesting. CM

Hazmatt_(The Underdog)

Sat Feb 24 2007, 09:32PM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

CM, magnetic fields in magnets happen because all the electron spins are occuring in the same direction, causing A Current. That Current has an 'Up' driection, so it must also have a "Down' direction. It cannot only have the one direction or else it would not exhibit polarizability. Therefore in a simple way, the monopole could not and will not exist. It is fundamental to atomic structure.

A monople is akin to saying that you are going to make a + battery without the -.

Sat Feb 24 2007, 09:49PM

Banned on April 7, 2007
Registered Member #277 Joined: Fri Mar 03 2006, 10:15AM
Location: Florida
Posts: 157

Haz:

I am with you on the non-existence topic 99.9999 % But it's that last spec of a percent that worries me. In this age when we are discovering never before known planets almost monthly it seems, sending probes through space using ion propulsion, and papers on quantum mechanics are being published that continue describing the deeper, more complex, and oftentimes counter-intuitive nature of the universe (as an old example, Bell's theorm that mathmatically proves that reality is non-local, to the satisfaction of the majority). I'm all for you being sure about it, I am too... almost.

AndrewM

Sat Feb 24 2007, 11:26PM

Registered Member #49 Joined: Thu Feb 09 2006, 04:05AM
Location: Bigass Pile of Penguins
Posts: 362

CM, you keep saying things like this:

The Halbach array appears to have only one pole to the human senses, (that is if you play around with it, placing it close to metalic objects or other magnets, etc) but we know that it has two poles. It's impersonating a one-pole magnet when examined only by the use of human senses. Under any type of scientific investigation, it can clearly be seen that it has two poles, but we know the reason it behaves as a one-pole magnet is because the 2nd pole is nearly cancelled out. I encourage folks to build one, they are very interesting.

I think the issue is that you simply haven't played with enough magnets. Get a horseshoe magnet and carefully consider how different it may or may not be...

Sun Feb 25 2007, 12:07PM

Banned on April 7, 2007
Registered Member #277 Joined: Fri Mar 03 2006, 10:15AM
Location: Florida
Posts: 157

Andrew:

It's been suggested to me by a monitor that I should avoid mentioning specific dollar amounts in my posts as it reportedly makes some members uncomfortable, fair enough. I'll speak in general terms, over the years I've collected an extensive archive of mags, well into the thousands of dollars, including horseshoe mags. Currently, I'm doing some H2O repulsion experiments calling for some pretty hefty mags in a wild variety of shapes. I'm pretty familar with most of them having 'played' around with them for sometime now. Searching for something different than the normal mag arrays is what led me to building and testing a Halbach array. Anyway, I encourage those who are interested to spend the very few bucks necessary to buy the 5 mags required to build the simple Halbach array and decide for yourself if this is just another typical magnetic assembly, or something special. Taking someone else's word, including mine, is no substitute for actually experiencing the odd Halbach effect yourself. CM

AndrewM

Mon Feb 26 2007, 09:29PM

Registered Member #49 Joined: Thu Feb 09 2006, 04:05AM
Location: Bigass Pile of Penguins
Posts: 362

Sula hit on a good point, a point I intended to prove last week but decided to drop it so this thread would die quickly. However I've been challenged to 'experience' the array, and I will now do so, albeit with real numbers instead of handwaving.

It seems obvious to me (and Sulaiman as well) that the Halbach array doesn't really offer much advantage when viewed from a mass or volume standpoint. However, apart from the fact that one side appears shielded, the array doesn't offer much of a developed field advantage either. Compare these plots I've made of the flux density around a Halbach array, and around an array of the same magnets, but oriented with simple alternating polarity:

Note that the peak external field, and the field-distance relationship, is not much better in the Halbach array.

This sidesteps the issue, however. Various hype-sources call the maglev system Inductrak, and babbles about coils on the train: it seems safe to assume this is an inductive system. As such, what we care about, in terms of levitating power, is field gradient. Observe the Y component of field gradient moving in the X direction for the two cases:

1172524724 49 FT1630 Antihalbachgradient

Wow, pretty dramatic. I can't imagine any arrangement of magnets that would produce better results than the simplest one.

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