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Author Topic: A bunch of questions regarding radially magetized ring magnet.  (Read 26752 times)

gyulasun

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #15 on: August 16, 2017, 06:28:25 PM »
...
yes by wide I meant inner diameter, big hole.

yet compass needle(that can't reach magnet field lines would still point to earth pole?


Only in case the inner diameter of a radial ring is high (big) enough so that when
you approach this magnet with a compass alongside the ring's center line axis,
then the presence of the inner unipole field cannot influence the compass needle
any more. Likely sizes to experience this I speculate you would need an unipole ring
with inner diameter of say 20 cm and needle length say 2 cm.
Suppose the ring has an ID=12 cm only, then the same needle would surely be influenced
by the small center field of the unipole ring and the needle would not show
true Earth North pole any more due to the presence of a stronger than the Earth's field.

Quote
....
I will buy some magnets online meanwhile can you tell me which of (7) induction methods
would generate current when coil or magnet rotate.
...

No, I cannot, you need to explore that by doing tests.

Gyula

Magluvin

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #16 on: August 16, 2017, 11:25:00 PM »
I was looking into them for my resonant pendulum using the speaker coils as drivers and pickups. These magnets if pushed back and forth in the coil would have very dense field passing through the coil, with small tolerance. If we look at a speaker motor, the magnet is sandwiched between 2 plates, the top plate with a hole in the middle and the bottom plate with a post in the middle that is just smaller in dia than the top plate hole so the magnets poles have a path of shortest distance at that pole gap, saying that all the field of the mag is concentrated there. Well I say not all and the field is not as dense as it is directly out of the face of the magnet.

So possibly the best induction with one of these magnets is to pass the mag through a coil that is just bigger than the mag dia. And to increase the flux get another ring mag that the other can fit into the larger ones hole with a gap for the coil. So now you have magnets on the outside and inside the coil. very dense field and all of the winding is induced, not just portions of it like in motors.

Then you can get another pair of those rings, with opposite poles of the first 2 and put them on axis near the first set and have another coil in that to generate also. The point is now you can put a rod core in the holes of the inner mags, which would link them magnetically, and an outer tube core to magnetically connect the outer diameters of the mags to close the magnetic loop, making the flux in the gap that much stronger.

Like a rod magnet, when it is just in open air, the fields at the poles faces are not as strong and or dense as they would be say per sq mm as it would be if the field had a core to use as a more direct path back to the other pole. So there is a flowering out of the fields from the poles making them less dense at the time. Probably the best reason why is that like polls repel, once it is out of the magnetic medium.  When a polarized field is in say an iron nail, the iron seems to neutralize the effect of the field wanting to flower out and repel its near by field of like polarity. Like they are attracted to each other when in the iron and the iron just may not be attracting the field, it may just be a medium that the fields issues with its close neighbor are negated and they can live together there in the iron. But once out of the iron they spread like a colony of bats out of a cave hole

So when we examine magnets by themselves the N pole is not just coming out of the face of the pole, some comes from around the sides on that half of the magnet and similarly at the S pole. When the fields come out of the face of the mag, they immediately start doing this i hate my neighbor thing, thus the spread of the field and that is translated within the magnet where they are being pulled away due to what is going on outside the magnetic medium.  So adding the path core to shorten the loops from N to S, then at the faces the flux gathering in the iron core in close proximity helps to make the pole face field denser and feel stronger.

So by adding the cores to the double dual ring mag gen, the field at the gap should be incredibly dense and strong, all making for a very efficient gen or motor, like a speaker.

Since standard speaker motors use a gap in between 2 cores that carry each mag fields to the coil gap, there is leakage that Im afraid hurts the field at the gap. Like if you look at most standard speaker motors the plates that capture the fields are a lot less volume of mass than the surface of the mags have to give. So as you can see by bringing a speaker near a crt, that field is leakin jim.    But if the coil is directly in the gap of 2 magnets instead and just use the cores as outer an center field looping, Id say the field in the gap would be a way better use of the field than the standard speaker motor which are pretty eff already as is.



mags
« Last Edit: August 17, 2017, 02:39:50 AM by Magluvin »

triffid

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #17 on: August 17, 2017, 03:55:18 PM »
test,just wanted a link back to this thread.triffid

Magluvin

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #18 on: August 19, 2017, 09:24:32 AM »
I was asked to clarify some things in my last post..

Normal speakers have axially mag poles and they use the top plate and the bottom pole plate to bring the fields of the magnet to the coil gap.

Where in my post I would like to try these radially magnetized magnets, a large ring and a smaller ring that fits the hole of the larger ring with space enough for the coil to move within, both with same poles in and same poles out, N out S in for example. I believe that the field between the 2 rings( inner S pole of the large ring and outer N pole on the inner ring) would have a denser field in the gap, rather than just making cores(top plate and bottom pole plate to basically carry the fields of the magnet to the gap. I think there is a lot of flux wasted that way due to leakage, like I said when you bring a speaker near a crt, that flux didnt make it from the magnet through the cores to the gap. So I would like to reverse that and make the coil gap with the actual pole faces of the mags, where the inner ring is attracted to the outer ring, and then the inner rod core and the outer tube core to close the magnetic circuit. Even if there are loses in the circuit closing cores, the gap between the magnets will still be denser than having the core carry it to the gap.

mags

mags


Magluvin

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #19 on: August 19, 2017, 10:42:32 AM »
here are pics

First is a normal magnet motor using the top plate and the bottom pole plate to bring the magnets fields to the coil gap

Second is closer to what Im getting at, but they only have 1 ring magnet on the outer side of the coil and just core on the inner side, of which the core just does not completely contain the field. Did like 5 vids on this subject. So I think the field would be denser if the inner pole had a ring mag too.

Cant get deep into it right now, but I believe there is a difference between flux density and actual field strength, where I think that expanded fields outside of a magnetic medium are weaker and possibly further more attribute to a weaker pole at the face, not just because of density at the face. Will be testing that theory.  If we have 2 mags in attraction with some measuring device to detect the pull force, and then we add a core to give the outer poles a shorter path to the other, will the pull force between the mags increase?  In that, without the outer return core, is the flux density between the 2 attracted mags any more when we add the return core( if not why), or is the field stronger because the flux loops are shorter rather than open air loops that can expand basically infinitely?  When the 2 mags are spaced face to face very close, there is little if any flowering of the field at the poles and the percentage of it all being there in the short gap is very high.  So if we add the outer return cores, and the force between the 2 mags increases substantially, can we only attribute that to the smaller percentage of flux density possibly added by adding the cores to have even less flowering at the gap?   I think its more of the shortening of the loop that increases field strength, along with density, naturally.

So that is why Im looking into this ring magnet idea also.  Like the 2 mags face to face to measure the pull, that outer core would have to be massive to contain the highest percentages of the return flux.  So in the sec pic example, Im betting on better flux density with an inner and outs mag ring around the coil will do better than core to core and even mag to core gaps. 

The mag pull test could be done with a short return core vs a longer larger return core to see if shorter loops create a stronger gap. dunno yet, gota git back to work work. As in making a living.

Mags

Magluvin

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #20 on: August 19, 2017, 10:54:17 AM »
Another thing is the difference in coil vs gap.  The first pic shows an overhung coil where only a portion of it is in the densest flux in the gap, and the second, which I prefer, is an underhung coil which all of the windings are in the flux at all times.  In the overhung, parts of the coil that go out of the flux when moving are wasting input power, where the unerhung is not.

So these are things to consider if you are using these rings. Been thinking on it all for some time and Im giving what I know of it to you.  Pushing the levels and limits on these things leads to more output.  If we took a toy motor apart and replaced the magnets with weaker ones, we would have the same or more current flow into the armature and less speed and torque. Now we put in stronger mags, more speed and torque. Then stronger mags, more speed and torque.  So gen or motor, the stronger the mags the better the performance.

Mags

Magluvin

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #21 on: August 19, 2017, 11:08:56 AM »
Found a good example of how the dual sets of rings would work

Here in the pic JBL is doing it with 3 stacked strontium mags and the top plat has a pole gap and the bottom plate has a pole gap.  So we get rid of the 3 mags, and replace the top and bottom plates with neo ring mags, and replace the inner pole with the 2 smaller ring mags and center them with an inner core rod, and make an outer core tube for the outer dia of the large rings. So the bottom large and small ring have S outer dia and the top rings have N outer dia poles Now the 2 coils, just reverse polarity one coil and connect in series or parallel with each other.

Mags

Magluvin

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #22 on: August 19, 2017, 11:11:04 AM »
Except my rendition would have taller mags with underhung coils

Mags

gyulasun

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #23 on: August 19, 2017, 04:03:54 PM »
...
   .... a large ring and a smaller ring that fits the hole of the larger ring with space enough for the coil
to move within, both with same poles in and same poles out, N out S in for example.
...
   .... where the inner ring is attracted to the outer ring, and then the inner rod core and the outer
tube core to close the magnetic circuit. Even if there are loses in the circuit closing cores, the gap
between the magnets will still be denser than having the core carry it to the gap.
...

Hi Mags,

Yes, it is very possible the magnetic flux density would be higher between two radially magnetized
ring magnets when one of them is embedded into the other. I have made a drawing as you described,
and although I did not include the inner rod and the outer tube cores for closing the magnetic circuit,
it is a must to utilize all the flux available in the two rings AND increase magnetic field in the gap manyfold. 
By the way, the magnetic circuit between your mentioned rod and tube could be closed by both a soft steel
ring or by just a third radially magnetized ring magnet, both with the correct ID and OD sizes to fit to the rod
and to the tube.  When you use a third radial magnet between the rod and tube to close the magnetic
circuit of the first two rings, the field in the gap can increase even higher than with a soft iron ring.

...
  If we have 2 mags in attraction with some measuring device to detect the pull force, and then we add
 a core to give the outer poles a shorter path to the other, will the pull force between the mags increase? 

Yes it will.  Just consider a magnetic door lock in which a simple ceramic block magnet is used with two
soft iron plates. The plates fully cover the side poles of the magnet (that is magnetized through its thickness)
and the magnetic circuit is closed between an outside third plate (to which the locking happens) and the two
iron plates that outreach the magnet.  The two soft iron plates 'collect' and focus most of the fields coming from
the sides of the magnet and make the attraction force to a third plate stronger, this is the same 'trick'
you can find in pot magnets and of course in speakers.

Quote
...
 So if we add the outer return cores, and the force between the 2 mags increases substantially, can we only
attribute that to the smaller percentage of flux density possibly added by adding the cores to have even less
flowering at the gap?   I think its more of the shortening of the loop that increases field strength,
along with density, naturally.

I think the first and stronger factor responsible for a stronger field is the less flowering i.e. less possibility
for stray fields and the second factor is the length of the loop. For this latter factor I think the cross section
area and the permeability of the soft iron material used for closing the magnetic circuit do matter.

Gyula

Magluvin

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #24 on: August 19, 2017, 04:41:18 PM »
Yeah thats the idea you drew there. The second set would be of opposite polarity. And yes the rod and outer tube could be magnets. Id rather they were magnets as I think there is too much leakage with iron core paths.   I said it before, I wonder if the core paths were made of neo but not magnetized, if they would work better than iron?

Mags

gyulasun

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #25 on: August 19, 2017, 09:28:03 PM »
Quote
Id rather they were magnets as I think there is too much leakage with iron core paths. 

Well, it depends...  See this hard disk picture with its back plate behind it (I took the pictures
from this site: http://www.reuk.co.uk/wordpress/wind/hard-disk-drive-magnets-for-wind-turbines/ )
You know such magnets are quadrapole ones, they act like two magnets stuck together side by side.
On one face there is a South pole on the left and a North pole on the right, on the other face there is
a North pole on the left and a South pole on the right. And the back plate connects the N and S poles
that are at the bottom face. Some time ago I checked with an office pin how magnetic the back side of
such a back plate + magnet assembly had been. The pin was not attracted to the back of the backing plate,
this means the plate surely had high permeability and was thick enough to avoid saturation so a negligible
amount of flux could exit (i.e. leak) from the back of the plate.

Quote
I said it before, I wonder if the core paths were made of neo but not magnetized, if they would work
 better than iron?

I have not had a chance to have such unmagnetized material so I do not know, I assume they should have
a high magnetic permeability before the magnetization.  Such materials should have the same rigid, hard
and next to impossible to form_to_shape properties like the Neo or any other permanent magnets have.
I think even if one had say metglas material, he would have a hard time to shape it.

One more notice: if you use magnets to complete a magnetic circuit, you need to stack several of them
to reduce their own leakage too.   Also, at most uncovered surfaces of a magnet the lines of flux can freely
come out because all the body of a magnet is in an almost complete saturation, while the same lines of flux
'have a hard time'  to come out from a highly permeable soft iron material like the backing plate of a HD magnet. 

Gyula

lancaIV

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #26 on: August 20, 2017, 02:19:40 PM »
Hello questions-bunch holder,here probably a "brainstorm"-questions/answer treasure :
https://worldwide.espacenet.com/publicationDetails/biblio?CC=DE&NR=19741256A1&KC=A1&FT=D#

I would prefer to increase "mon-ocle view" views by twi(ce)light and then tri-nity-lightning with 4d-thinking
                                                        and real material use experimenting.

Also testing 1 ball-cup generator (or motor) with supplement to 2-ball-cup-system .

Happy day
                 OCWL

Magluvin

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #27 on: August 20, 2017, 04:10:47 PM »
Well, it depends...  See this hard disk picture with its back plate behind it (I took the pictures
from this site: http://www.reuk.co.uk/wordpress/wind/hard-disk-drive-magnets-for-wind-turbines/ )
You know such magnets are quadrapole ones, they act like two magnets stuck together side by side.
On one face there is a South pole on the left and a North pole on the right, on the other face there is
a North pole on the left and a South pole on the right. And the back plate connects the N and S poles
that are at the bottom face. Some time ago I checked with an office pin how magnetic the back side of
such a back plate + magnet assembly had been. The pin was not attracted to the back of the backing plate,
this means the plate surely had high permeability and was thick enough to avoid saturation so a negligible
amount of flux could exit (i.e. leak) from the back of the plate.

I have not had a chance to have such unmagnetized material so I do not know, I assume they should have
a high magnetic permeability before the magnetization.  Such materials should have the same rigid, hard
and next to impossible to form_to_shape properties like the Neo or any other permanent magnets have.
I think even if one had say metglas material, he would have a hard time to shape it.

One more notice: if you use magnets to complete a magnetic circuit, you need to stack several of them
to reduce their own leakage too.   Also, at most uncovered surfaces of a magnet the lines of flux can freely
come out because all the body of a magnet is in an almost complete saturation, while the same lines of flux
'have a hard time'  to come out from a highly permeable soft iron material like the backing plate of a HD magnet. 

Gyula

This is why I believe that there will be more flux density between 2 magnet faces than from a magnet to a return core or even core to return core with remote magnet.

If we have a magnet facing another magnet, both already have very dense fields within. If it were magnet to return core, the gap end of the core is not going to hold or say carry all that flux from the other end of the magnet to the gap due to leakage of the core. And then in the case with the standard speaker motor with top plate and bottom pole plate, there will never be as much flux in the gap as there would be in the next better step, magnet to core gap. So having the magnet on both sides of the gap would be the densest field in the gap. Was reading on speaker design(not a lot out there like its forbidden knowledge. Only 2 software progs out there specific for speaker driver design exist as far as I know at this time and very pricey) and one of the ingredients to increasing the eff/sensitivity of the driver is to have a stronger mag field in the gap.  Im looking into creating my own subwoofers. Looked into a couple companies in china and they dont even know what Theil/Small parameters are, which are all the specs that are used to evaluate and calculate proper enclosures for each. These companies seem to just bang out what looks good, big triple stack magnets, large rubber surrounds, long heavy voice coils(most all overhung up to possibly only 1/8th of the coil in the gap. What a waste of power.) capable of taking on thousands of watts. Its a scam.

About 7 years ago Pioneer was beating everyone at SPL contests. They had subs that were longer than they were wide, 5000w to 8000w.  Now everyones in on it and raking in the cash.  After that pioneer dropped all the big equipment and went another route. They designed their speakers and subs to be more eff than most any out there, especially for the price, as the few others that have high sensitivity numbers charge big bucks.  Pioneers Champ Pro 12 is 96db @1w and can be had for under $100. They also have a pro 12 that is 105db @1w. Its more of a stage driver, not a bottom boom sub.  3db increase is a doubling of power. Many subs out there are under 90db @1w. So just in the case of the 2 pioneer 12s, the champ needs 4 times the power to just catch up to the pro 12. Im ordering one of those pro 12s 105db just to try it and compare to the champ.



So my buddy has 6 PSI 15in subs powered by 15kw in amps. His subs are 88.5db@1w.  My other friend, we are going to do 6 Pioneer champ pro 12s with only 5200w and they are 96db@1w ea.
My first bud needs to increase his amp setup to 30kw to beat the pioneer system that is only running 5200w. So now we are really seeing what efficiency can do for us.
My buddy with the PSI 15s is going to regret ignoring me on this subject and going with expensive monster equipment, spending over 10k vs 1k for equipment, let alone wires, etc.  Each of his amps take 2 + 0awg and 2 - 0awg.  Lots invested in that. His amps may not be super eff either. Thats another post.

So if you see the graphs of each setup in the WinIsd Beta speaker box program, it is ridiculous what people are spending because they dont know what the sensitivity spec is, and the ones that do have this idea that more is better.  Nuts

So Im going for a sub design that is aiming for efficiency. Hopefully more than whats available. The highest I have seen yet is 112db@1w, but it wasnt a sub woofer exactly. More of a stage driver.

Mags

Magluvin

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #28 on: August 20, 2017, 04:32:09 PM »
Like simple pulse motors with say 1 coil and mags on a wheel. All of that is very inefficient. No return cores, open ended mags and coils. If just those things were installed, along with a full load of coils around the wheel, the same input will get you more output. The Pulse motor build off should be looking at these things. Actual measurements of the in and out and that should determine the winner. Not the coolest looking thing and all that jazz. But those numbers would be tough to prove without judge attendance, so it is what it is.

Mags

Magluvin

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Re: A bunch of questions regarding radially magetized ring magnet.
« Reply #29 on: August 20, 2017, 08:18:38 PM »
Just found a couple more software for speakers and some interesting fem pics. I gota put it up later though

Mags