Has anyone played with shielding materials such as MetGlas?
http://www.blockemf.com/catalog/product_info.php?cPath=757&products_id=5114
Looking here http://www.lessemf.com/faq-shie.html#Lead-Copper they quote the following:
Here's how the permeabilities of some common materials compare:
Air ........... 1
Copper ...... 1
Aluminum ... 1
Tin ............. 1
Lead .......... 1
Nickel .................. 100
Commercial Iron ... 200
Stainless Steel ....... 200
MagnetShield ........ 4000
Magnetic Shielding Alloys* ....... 20,000+
Annealed MetGlas ................. 1,000,000
Regards
Sean.
No replies on this one, so have ordered 10ft length to see if it will get over the sticky point.
Will post the results.
Regards
Sean.
Could you give us an example of where exactly on a magnetic motor would you be placing this insulating material? Where exactly is the spot that you are trying to insulate?
I look forward to hearing your results.
The easiest way is to look at simple wheel designs such as this that show shielding
http://www.fdp.nu/otherwheels/bartosz.asp?URL=bartosz.asp
Not saying it will work, but the logic is there.
Regards
Sean.
Quote from: thevorlon on October 22, 2006, 05:40:44 PM
Could you give us an example of where exactly on a magnetic motor would you be placing this insulating material? Where exactly is the spot that you are trying to insulate?
I look forward to hearing your results.
Ever consider building some Halbach arrays to put on the rotor? They amplify their magnetism on one side and cancle it on the other. It could *perhaps* help with these sticky points.
http://www.matchrockets.com/ether/halbach.html
Now thats interesting and easy enough to try out.
Thanks for the link.
Regards
Sean.
Quote from: thevorlon on October 22, 2006, 06:09:34 PM
Ever consider building some Halbach arrays to put on the rotor? They amplify their magnetism on one side and cancle it on the other. It could *perhaps* help with these sticky points.
http://www.matchrockets.com/ether/halbach.html
Just to let you know.
The material arrived, cost a fortune, delivery from USA to UK was more than the material, Customs hammer you a extra 17.5% and at the end of the day you get a roll of 1 inch tin foil that seems to have as much magnetic shielding as a piece of paper LOL
They state in the instructions that you can even wrap your magnets in it, why??? it makes no difference !!!
Do not waste your money, I have played with this material all week, from making a sandwich to keep the air space in the equation to wrapping a whole coil in the stuff.
I see no shielding here of magnetic fields at all, maybe ideal for distant shielding of speakers etc etc but as far as trying to divert the magnetic field to weaken it, a waste of time.
Well you learn and onto the next experiment!
Regards
Sean.
How big are the magnets you are trying to shield? Neo / Ferrite?
I have tried every magnet I have here, and that is a lot of different sorts LOL
The weakest ones I have are ferrite typical kidz magnets Painted Red at one end and struggle to pick up a washer! and even wrapping a layer of this stuff with a fair of bit of air space the field is very prominent.
Have tried various lengths to try divert the field but still seems the same. The only insteresting thing I did find was by playing a small strip on the end of my magnetic spiral wheel, the kick back did seem to increase.
Will go back and play some more when I get time, at the moment, got yet another wheel on the milling machine!!
Regards
Sean.
Quote from: konduct on November 04, 2006, 03:54:52 PM
How big are the magnets you are trying to shield? Neo / Ferrite?
Thanks for the warning. I think perhaps you should post this warning in the "fraudulent offers" section of the forum too.
Quote from: CLaNZeR on November 04, 2006, 03:44:43 PM
Just to let you know.
The material arrived, cost a fortune, delivery from USA to UK was more than the material, Customs hammer you a extra 17.5% and at the end of the day you get a roll of 1 inch tin foil that seems to have as much magnetic shielding as a piece of paper LOL
They state in the instructions that you can even wrap your magnets in it, why??? it makes no difference !!!
Do not waste your money, I have played with this material all week, from making a sandwich to keep the air space in the equation to wrapping a whole coil in the stuff.
I see no shielding here of magnetic fields at all, maybe ideal for distant shielding of speakers etc etc but as far as trying to divert the magnetic field to weaken it, a waste of time.
Well you learn and onto the next experiment!
Regards
Sean.
Well I do not know if we need to go that far.
It probably does well in shielding interference if you wrapped a cable in it but for what I want to use it for, a waste of time !!!!!
Show me a shield that can be layed on top of a magnetic pole, whatever shape, that will divert the field back around to the opposing pole, with the external side not effected by the field, then I will get excited, but I have not so far seen this claim and trying other materials that may do the job on fluke as such!!.
Regards
Sean.
Quote from: djancak on November 04, 2006, 04:08:02 PM
Thanks for the warning. I think perhaps you should post this warning in the "fraudulent offers" section of the forum too.
Quote from: CLaNZeR on November 04, 2006, 03:44:43 PM
Just to let you know.
The material arrived, cost a fortune, delivery from USA to UK was more than the material, Customs hammer you a extra 17.5% and at the end of the day you get a roll of 1 inch tin foil that seems to have as much magnetic shielding as a piece of paper LOL
They state in the instructions that you can even wrap your magnets in it, why??? it makes no difference !!!
Do not waste your money, I have played with this material all week, from making a sandwich to keep the air space in the equation to wrapping a whole coil in the stuff.
I see no shielding here of magnetic fields at all, maybe ideal for distant shielding of speakers etc etc but as far as trying to divert the magnetic field to weaken it, a waste of time.
Well you learn and onto the next experiment!
Regards
Sean.
I see you all are talking about magnetic shielding.
Shielding and total flux shorting are two different things.
I have found that if you use netic instead of conetic, it works better with near direct magnet contact. When you shield a magnet, you do not want the shield to touch the magnet. Layers that are separated work better at shielding magnetic field than one thicker layer. If your goal is to conduct flux from a magnet to short it out, a thick piece will be needed. However, the thicker that you get the netic, the more difficult it is to shape it. I would suggest that you ask the company that you order it from what the thickest sheet is that you can get, while still being able to shape it. One layer will not completely shield a magnetic field if you use neodymium magnets. Multiple layers will reduce it, kind of like using insulation to insulate a building. The higher the R-factor, the more it will insulate.
Netic will rust if kept in a humid area. It comes slightly oiled and is messy to deal with. I would suggest that when you get it the way you want it, clean it off and use clear coat laquer or something like that to keep the air from rusting it.
Just a few tips. Hope it helps.
I am not sure if this is what you are looking for but I have taken the magnets and the magnet shielding out of a computer hard drive and it seems to do pretty good job of at least shielding the magnetic force. The magnet will always attract to the shielding but beyond the shielding there is no attraction or repulsion.
Mike
Many thanks for the tips Liberty, well appreciated.
I have tried many different configs with this material this week, inlcuding sandwiching it between layers of different material from wood to vinyl. Various spacing from the magnets etc etc.
If I am honest I do not see any difference, so will leave it on the back burner and move onto the next thing onthe ToDo list !!
Regards
Sean.
Quote from: Liberty on November 04, 2006, 04:37:00 PM
I see you all are talking about magnetic shielding.
Shielding and total flux shorting are two different things.
I have found that if you use netic instead of conetic, it works better with near direct magnet contact. When you shield a magnet, you do not want the shield to touch the magnet. Layers that are separated work better at shielding magnetic field than one thicker layer. If your goal is to conduct flux from a magnet to short it out, a thick piece will be needed. However, the thicker that you get the netic, the more difficult it is to shape it. I would suggest that you ask the company that you order it from what the thickest sheet is that you can get, while still being able to shape it. One layer will not completely shield a magnetic field if you use neodymium magnets. Multiple layers will reduce it, kind of like using insulation to insulate a building. The higher the R-factor, the more it will insulate.
Netic will rust if kept in a humid area. It comes slightly oiled and is messy to deal with. I would suggest that when you get it the way you want it, clean it off and use clear coat laquer or something like that to keep the air from rusting it.
Just a few tips. Hope it helps.
Hi Mike
I read this in a previous post and it got me interested.
In the previous post they were saying that this shield was found in the old 5.25 Drives rather than the modern 3.5" drives that I have plenty of laying around.
What drive did you pull this out of?
Also I would be interested in knowing how easy the material can be pulled away from a magnet when sliding it rather than pulling?
Also if you form a air gap between this material and the magnet, does it still shield?
Where abouts on the Hard Drive is this material used?
Regards
Sean.
Quote from: mbell on November 04, 2006, 04:39:47 PM
I am not sure if this is what you are looking for but I have taken the magnets and the magnet shielding out of a computer hard drive and it seems to do pretty good job of at least shielding the magnetic force. The magnet will always attract to the shielding but beyond the shielding there is no attraction or repulsion.
Mike
I have a ton of hard drives laying around some old some new. Where i get this is from the end of the read write heads. There are two shields and the magnets are glued to the shields. The magnet will stick to the shield but will block any magnatism beyond that. It is hard to get the magnet away from the shield (because of the glue) and the magnets are very powerfull for their size. I am going to try this motor as I think it can be done useing the shields from the hard drive. http://www.fdp.nu/otherwheels/bartosz.asp?URL=bartosz.asp If you attach the shields to both magnets like it shows in the picture you should not get any attraction or repulsion until just before the magnets come face to face. The shields are in the new hard drives 3.5 inch and the are at the back end of the read write heads. They are like a half circle and the magnets are glued to them. The magnets are very easy to break so you have to be carefull if you want to save the magnets. I can post pictures of this if you need me to.
I think also if you use the hard drive as the turntable could you also get power out of the motor? This is what I am going to try as I think if you use the shields out of the hard drives and attach as shown in the picture it should work. (maybe) lol...
I hope this helps
Thanks
Mike
There is a concept of "shadowing" as distinct from "shielding" as discussed on:
http://tech.groups.yahoo.com/group/minatowheel/
Also, google for "parallel path" and check out "changing fields" on
http:www.fdp.nu
mu-metal has a reputation for shielding, although fields have a
way of leaking around the job.
Paul.
Quote from: CLaNZeR on October 22, 2006, 06:00:11 PM
The easiest way is to look at simple wheel designs such as this that show shielding
http://www.fdp.nu/otherwheels/bartosz.asp?URL=bartosz.asp
Not saying it will work, but the logic is there.
Quote from: thevorlon on October 22, 2006, 05:40:44 PM
Could you give us an example of where exactly on a magnetic motor would you be placing this insulating material? Where exactly is the spot that you are trying to insulate?
I look forward to hearing your results.
here is an idea using a shield I just drew up, the goal is to keep the shield in the exact center.
(https://overunityarchives.com/proxy.php?request=http%3A%2F%2Fimg.go-here.nl%2Fshielded-pistons.gif&hash=777f8dd49797164dd536d117043aee769a55354d)
If this would run down one could wrap a coil around the shield and pulse that. With all the exotic shielding material you have I think this kind of contraption looks most interesting?
:-)
Quote from: CLaNZeR on November 04, 2006, 05:03:50 PM
...
Also I would be interested in knowing how easy the material can be pulled away from a magnet when sliding it rather than pulling?
Also if you form a air gap between this material and the magnet, does it still shield?
...
Sean, this notion of sliding the shield rather than pulling directly away reminded me of an experiment I did. The shield was as close to touching the magnet as possible, and it was very attracted to the neo. When the shield covered the neo though, it almost perfectly turned it off. You could put iron bolts right against the shield and there was very little noticeable attraction, even though the distance was only a few mm. I found by using a strong elastic band to counter the shield's desire to cover the neo, I could create a close-to-equilibrium that made it quite easy to slide the shield on and off. Here's a crude picture:
(https://overunityarchives.com/proxy.php?request=http%3A%2F%2Fwww.overunity.com%2Findex.php%3Faction%3Ddlattach%3Btopic%3D171.0%3Battach%3D6347&hash=3e2e437d83a7800490f399a5879248ed5591a687)
Reade
Found this clip ..someone playing around with robbed hard drive mags and some type of shielding strip from a DC motor....
http://www.youtube.com/watch?v=yf2oybnz-vQ
the trick of shielding is in closing the magnetic loop with it. If done well only one kind of flux propagates beyond it. Either north or south but never both. It should be simple to build a spinning device. It wont have much power but it can be made to work. For real power you would need to switch the flux in big cores rather then thin sheets.
One step at a time :-)
Then there is a way of placing the shield on the domain wall. Thats also " shielding" but quite different.
The problem with shielding is that the shield will mimic the same magnetic field as the magnet (with reversed poles of course). I tried to use shielding to weaken, periodically, the magnetic field coming from a permanent magnet and going into a coil. The flux from the shield was such that it matched with the flux generated from the coil. So in the end, it was the same as just moving the permanent magnet back and forth - the counter torque was not reduced at all with the shielding. I abandoned this idea.
It is true however, you want to make the shield as thick as possible. You don't need mu-metal. Steel plumbing pipe found at any hardware store (or Lowes) is about 3/16 to 1/4 inch thick and makes a great shield - and is really cheap. Mu-metal is just too expensive and you need so many layers. Low carbon steels also work better because they have higher saturation than normal steels.
But like I said earlier, shielding does not work - atleast what I've tried, and I tried many many arrangements. You want to destroy the back EMF's affect on the prime mover and I'm fairly certain that shielding is not the way to do that.
Quote from: superhero on March 17, 2014, 06:54:11 PM
Have anyone ever studied the effects of lenses on the magnetic field
Hi Superhero,
No it never occured to me... you mean optical lenses, right? If you do, is there any hint that made you ask this question? Perhaps you tested it?
Gyula
The best solution would be to figure out what is acually happening in the center of a simple bar magnet. Is it a depletion zone, the action of a vortex, or what. If we can move the null point inside the magnet to one end it should make the flux almost non exist on that end. I know what he is up to and I won't really tell. The simple explanation is he hit the perfect number of rotating magnets around a rotating magnetic armature with the right number of poles and, knows the proper gearing for the outside ring of rotating magnets and wants to build a motor.
Quote from: superhero on March 17, 2014, 06:54:11 PM
Have anyone ever studied the effects of lenses on the magnetic field
Magnetic fields do not "project" out of an object like a ray. They come out of it. A line of magnetic flux exists at each point
around a loop. It's kind of a touchy feely way of making sure that anything crossing the magnetic field line gets
integrated into the loop as a whole. So while one can redirect magnetic flux around a gap you can not project it
across a gap, focusing and insulation are generally therefore not available to static magnetic field.
:S:MarkSCoffman
As I am not really aware of this: just a silly question: as far as I understand that physical shape of magnet does not affect much about the shape of the magnetic field? else than smaller=weaker?
Just thinking about the directing of field. or perhaps using other magnets ot compromise it.. but I think that if this would be so easy this problem would be solved already..
On other hand I think that some magnetic motors should use some kind of cam drive mecanism to have "timing" on the attracting magnet.. and a decent flywheel.
Geometric shapes have a lot to do with it. Johnson's magnetic motor, is one example. I had a magnet from GE, it misteriously disappeared after it had been posted in here in the past. It had a Angle about 45 degrees on one end. I had a picture of it here long ago, maybe it can be dug up? All the magnets I had are gone. It might be here somewhere but, I have given up looking.
the perfect shielding are magnets that repels each other as in North to North and South to South as cushioning's to each other without any metal to metal frictions either !!! I am putting two diagrams to show you this
Thomas C.
here is a link to help with pyrolytic graphite shields or repels magnetic fields too
http://en.wikipedia.org/wiki/Pyrolytic_carbon
http://en.wikipedia.org/wiki/Diamagnetism
I hope this helps you guys out
Tom
The best known magnetic shielding is magnets themselves with North repels North and South repels South right Hint Hint !!!
Thomas
Quote from: CLaNZeR on October 03, 2006, 06:16:00 AM
Has anyone played with shielding materials such as MetGlas?
http://www.blockemf.com/catalog/product_info.php?cPath=757&products_id=5114 (http://www.blockemf.com/catalog/product_info.php?cPath=757&products_id=5114)
Looking here http://www.lessemf.com/faq-shie.html#Lead-Copper (http://www.lessemf.com/faq-shie.html#Lead-Copper) they quote the following:
Here's how the permeabilities of some common materials compare:
Air ........... 1
Copper ...... 1
Aluminum ... 1
Tin ............. 1
Lead .......... 1
Nickel .................. 100
Commercial Iron ... 200
Stainless Steel ....... 200
MagnetShield ........ 4000
Magnetic Shielding Alloys* ....... 20,000+
Annealed MetGlas ................. 1,000,000
Regards
Sean.
Shielding is a confused term when it comes to magnets. Magnetic materials GUDES the magnetic field somewhere else than where the field lines would go in thin air. Not shielding them.
This guide will have an impact on the magnet - as these materials are attracted to the magnet, and vica verca. Using these magnetic materials will definitely not help you pass the sticky spot. And if you for some reason don't have a sticky spot anymore, the system will not longer work because there are no magnetic fields left to "power" anything.
Vidar