Greetings to the community. This post is to introduce you to the principle and current development of a device that I have dubbed the "Switched Flux Transmission", or SFT for short.
While watching one of Robert Murray-Smith's videos called, "The secret of magnetic motors", on his Thinking & Tinkering YouTube channel, I got to thinking about flux circuits and it led me to the following observations:
1. When you hold two magnets with their opposite poles facing they attract.
2. When you hold two magnets with their like poles facing they repel.
3. If you insert a steel sheet between two like poles both poles are attracted to the sheet; you have, in fact, by introducing the sheet, switched the magnetic flux from repulsion to attraction.
You may say that this is no novel discovery but, whilst people quickly and intuitively answer the questions "What happens if ..." to the first two statements, many people are slow and uncertain to answer in relation to the third. It seems to me that most explorers in search of a design for a Permanent Magnet Motor have concentrated on the attractive force of opposite poles and I have not been able to easily imagine such a configuration that will generate a useful switching action. Observation 3 above though offers an easy way to take advantage of flux switching.
Examine the following device:
(https://tomboy-pink.co.uk/SFT/media/banner.png)
The device consists of a magnetically permeable rotor (made from any magnetisable material like soft iron etc) with tabs or 'fingers' around the circumference. There are two rockers or bellcranks, one either side of the rotor and arranged such that each rocker presents a magnet to face the rotor fingers. The rotor has an odd number of fingers so that when there is a finger in the magnetic gap on one side there is no finger in the gap on the other side. Thus, turning the rotor switches the magnetic fields between the magnets from repulsion (when there is no finger) and attraction (when there is one).
It is my hypothesis - which has been confirmed by experiment - that the energy produced by the flux switching is greater than the energy required to turn the rotor. Now, these experiments so far have been rough and ready - I am not suggesting they provide solid, scientific proof of my assertion - but they have been independently confirmed by another interested party.
I have been through a development process consisting of a number of designs and have built one prototype of an earlier design but that prototype was small and difficult to adjust and had an exotic power transmission linkage that was rather difficult to realise at that scale. So now I am at the stage of building the Mark 5 version, for which the design has been completed and I am now awaiting a date from FabLab to go in and print the parts.
The design, along with all the CAD files to build the device, I have released with an 'unlicense' public domain license that allows anyone to copy, build and develop the idea. It's about as open source as you can get and there is nothing that I know about the principle or practice of building it that I have not made freely available.
The place to start in exploring this idea is my web page dedicated to the device: http://tomboy-pink.co.uk/SFT That page also gives links to my GitHub repository with the full CAD model and STL files as well as links to discussions about the device on scienceforums.net
I hope you find it interesting and inspiring. I will keep my web page updated as I continue to develop the device but there is no forum for discussion there, hopefully there can be a good discussion here.
Best regards,
Prajna Pranab
Hello Prajna,
Thanks for posting here your interesting setup.
However, after I have checked out your supplied info so far (in your other site) I find that you still need to produce more information:
As I understand you are still in the process to build (physically) a better sized prototype, You still need to provide the CAD Views in 2D of Front, Side and Top views.
So, we can have "a more complete idea" of how this principle works, as where does it triggers to follow a sequential timing?
A shot in perspective that you have shown so far everywhere, is NOT enough to have a full idea.
Normally in Engineering, you FIRST need to supply the 2D Views I have mentioned before, THEN, AFTER a Perspective or Isometric View will give the final "wrap" of the whole design.
Now, related to your Statement #3:Quote3. If you insert a steel sheet between two like poles both poles are attracted to the sheet; you have, in fact, by introducing the sheet, switched the magnetic flux from repulsion to attraction.
That assumption above (basically the bold out part by me) is not quite correct, and it may tend to confusion in basic MAGNETISM PROPERTIES.
It depends on MANY different Parameters to consider, as it will have many VARIATIONS IN RESULTS:
1- Mass and Volume of the Steel Plate.
2- Grade of Permanent Magnets (if they are "twins or identical" or are different grades).
3- Gap between Magnet-Plate-Magnet.
Plus, another objection, the same polarity magnets NEVER Change their natural origin because a steel plate is present, both always keep their same polarity, and are just being attracted to the steel mass.
Therefore, there is STILL a Repulsion, but FORCED by the steel plate to COEXIST CLOSELY, based on their attraction to steel.
Again, if you use the same Neodymium Grade and shape magnets, say 52 Grade, and use just a Thin Steel Plate in between, you will still have a "Repulsion feel" when approaching them to the plate at unison (closing gap equally to steel).
I am also working -at present- on a similar project, where I am using steel in between same polarities magnets to achieve rotation of the steel.
Except my magnetic fields (magnets) are completely static, as "Stators".
Regards
Ufopolitics
EDIT 1: In addition, when we approach JUST ONE magnet pole to steel, we are EXPANDING that Pole within the steel, this can clearly be observed with Magnetic Viewing Film. And I have videos where I show this clearly.
As we observe the magnet approached to steel Bloch Wall to MOVE towards the steel. This CONFIRMS what I am saying...Pole gets EXPANDED towards the close Steel.
@Ufopolitics, his magnets are fixed in this setup, when steel spinning disc is in between 2 north or 2 south depending on his areangement, both magnets will be attracted to the disc. When a slot is between magnets, both magnets are in repulsion.
So, when disc with slots is spinning there will be an alternate polarity ... I didn't try but, my guess as long as disc can rotate free between magnets assuming magnets do not touch the disc to introduce friction in equation.
There is a hint: https://rumble.com/v4odo38-joe-may-2010-magnetic.html
How to take full advatange of this method of magnetic flux switch ? I don't know, I didn't explore kinectic systems, I have a preference for solid state where I am focused.
Also, this is explained in a different way by David Davis Jr in his Manual of magnetism. See attached picture and manual pdf IMG_0232.png
Quote from: Classic on Jun 25, 2024, 01:23 PM@Ufopolitics, his magnets are fixed in this setup
Hello Classic,
Sorry to disagree with you, but no,
his magnets are not fixed.
As I understand it, there are Four total magnets set facing at repulse mode and mounted one for each swivel arm end.
Swivel arms,
when they MOVE (carrying also the two magnets in the movement) Arms close on one end, as they open at the opposite end...
Concluding, magnets do move as swivel arms move... ;D
Cheers
Ufopolitics
Quote from: Ufopolitics on Jun 25, 2024, 09:38 AMHowever, after I have checked out your supplied info so far (in your other site) I find that you still need to produce more information:
Quote3. If you insert a steel sheet between two like poles both poles are attracted to the sheet; you have, in fact, by introducing the sheet, switched the magnetic flux from repulsion to attraction.
That assumption above (basically the bold out part by me) is not quite correct, and it may tend to confusion in basic MAGNETISM PROPERTIES.
Hi @Ufopolitics, thanks for your response. I will do technical drawings of the device but that happens in a different workbench in FreeCAD, which I am not really familiar with yet. I have been concentrating on the modelling and slicing for 3D printing (which I managed to get started today, yay!) Anyone who is familiar with FreeCAD can download the complete model from my GitHub (linked from my SFT web page) and look at it from all angles.
I am using 10mm x 3mm Neo disc magnets (they're what I have). I am not sure if they are N52 or N32 but they seem quite strong. From the tests I have done a 1mm sheet of steel is sufficient to 'colapse the repulsion', if I can put it that way (I know that's not a technical description and I would never get away with using such terms on scienceforums.net but I hope you understand what I mean). My experiments showed me that the main repulsive field extends about 40mm between the magnets, which is why I set that gap between the magnets in the device - each bellcrank (rocker arm) can move backwards and forwards by 20mm, allowing the magnets to be 40mm apart at their most distant point. The crank pin in the flywheel is 20mm from it's centre and that limits the travel of the bellcranks so that the magnets are never more than 40mm apart and they never get close enough together to actually touch and clamp to the rotor. (hopefully that will also answer to @Classic's reply above as well).
To better understand the device it might be helpful to look at the previous version, which is linked from the SFT page. That version (although it is a differnt arrangement) works on the same principle and there is a link to an animation of the device running.
I did try to get some sense out of the physicists on scienceforums.net but that is like milking a bull! Hence I decided that the only way to prove the idea is to build and test it, which is what I am in the process of doing.
When I was in FabLab today some Portuguese Admiral turned up with an entourage. They asked about what I was working on, so I explained to some of the younger officers, who all nodded and seemed to think it would work. One of the officers then explained to the Admiral in Portuguese and he immediately said, "It won't work." I just shook his hand and said, "Bet."
So, half the base is being printed today (8 hour print) and I hope to print the other half tomorrow. There are three more full prints to do after that and I am hoping to get the rotor laser cut as well (Fablab in Fundão can't do that but I've heard that FabLab in Covilhã might be able to), otherwise I will have to do that myself with drills, cutoff disc and files. If I can get it laser cut then I can get, say, three 1mm thick rotors cut out and fit perhaps three of them together if needed to give the mass necessary to cancel the repulsion. If I have to do it by hand I'll just go straight for a 3mm rotor (since I have 3mm sheet to hand).
I will do some proper technical drawings when I can but it will be some time before I have a chance to get up to speed on FreeCAD's Tech Draw workbench and at the moment I am focused on getting the prototype built so I can test it.
Thanks for replying and I welcome any more questions or pointers.
regards,
Prajna
Quote from: Ufopolitics on Jun 25, 2024, 01:51 PMQuote from: Classic on Jun 25, 2024, 01:23 PM@Ufopolitics, his magnets are fixed in this setup
Hello Classic,
Sorry to disagree with you, but no, his magnets are not fixed.
The magnets are embedded in the ends of the bellcranks or rocker arms. The opposing magnets do move in relation to each other - in fact they move up to 40mm apart and approach as close to the rotor fingers as they can without actually touching it (the limits of their movement can be adjusted - one of the reasons I needed to redesign the device was to introduce this adjustment mechanism).
I hope that clarifies things.
regards,
Prajna
I got it, many thanks for explanations. I had a different picture in my mind and obviously is missed that part on initial description.
It seems far more complicated then it should be ... from what I see this is a non starter for diy replication unless someone spend a lot of many ordering parts or have an extensive mechanical workshop. None the less looks very intersting, looking forward for tests and proof of concept.
Quote from: Classic on Jun 25, 2024, 04:30 PMI got it, many thanks for explanations. I had a different picture in my mind and obviously is missed that part on initial description.
It seems far more complicated then it should be ... from what I see this is a non starter for diy replication unless someone spend a lot of many ordering parts or have an extensive mechanical workshop. None the less looks very intersting, looking forward for tests and proof of concept.
Well, I live in a caravan and my workshop is mostly mother nature at the moment. I have basic tools and I'm just using 3D printing at FabLab. Really they just charge for the materials and a bit of time. This version is just to clearly demonstrate the principle and to offer proof of that principle, if the device performs as my experiments lead me to believe it will. It can be made in many configurations - some I have already thought some way through. Having sprung magnets in solenoids might be practical. But let's prove the idea before having to explain electrics and electronics to people.
I understand the principle, so I am able to imagine many different ways to use it, if my understanding is correct. I don't think it is difficult to grasp; my local village café owner, who is also a farmer and runs the village shop, immediately understood what I was showing him - which is quite something because my Portuguese is rudimentary.
If people would like information about it, I have made it freely available and people are welcome to repliacte it in any form. I'd be interested to hear about replications. On another forum someone commented that they had carried out their own experiments and their results confirmed the claims I put forward.
The bearings were very expensive here. They cost 36.96 euros for the three. Bearing Boyz online offer them for a couple of quid each but that would involve postage and that would involve the Portuguese post office and that would involve ... so I paid the premium but others don't have to.
5mm steel (or even stainless steel if you're feeling flush) rods are quite cheap. 5mm allthread likewise. M5 nuts, screws and washers, not much (watch out though, some of the China shop nuts are of varying quality and some may not be close enough for embedding in the print).
regards,
Prajna
Hello and thanks
@Prajna for your detailed explanation(s)
I do see how the mechanism of both swivel arms with magnets works with the rotor uneven slots-'fingers'.
So, when rotor metal is at magnetic gap on one side, this closes arms carrying both magnets (attraction), while at 180 degrees there is an open gap, allowing repulsion forces to act fully.
These Repulsion forces "assist" the closing on gap at other side...and so on, it keeps balancing the arms back-forth movement.
But honestly, what I am failing to see, is the propulsion mechanism that would cause rotor to spin[color=var(--input-txt-color)]...because this attraction points from both end magnets would tend to stop/brake rotor,[/color]
like a "Brake Caliper Effect"...and I do not see the Repulsion at opposite end to cause rotation, but only to compensate/assist the attraction on other end.
Anyways, I wish you a great build, and would be waiting to see results.
Btw, do you have any videos, even on the old setup, that you could upload here?
It would be great to see mechanisms working.
Regards
Ufopolitics
Quote from: Ufopolitics on Jun 25, 2024, 06:09 PMHello and thanks @Prajna for your detailed explanation(s)
Btw, do you have any videos, even on the old setup, that you could upload here?
It would be great to see mechanisms working.
Regards
Ufopolitics
Sure, my channel is https://m.youtube.com/channel/UCuXjvvt722O9R1PIg9ILMog - it's the Mk-4 version but it should give you the idea.
That version had a big handle to indicate that the rotor does not turn itself, it must be driven. All this is explained on my webpage. The point is that if the energy required to turn the rotor is less than the energy output by the flux switching then we can drive the rotor from the output (by any means known to someone skilled in the art, as they say) and, we hope, have a useful remaining output).
I hope that was useful.
Regards,
Prajna
Thanks Prajna!
I uploaded a couple of your videos here:
Ufopolitics
It all depends on how it will perform under load or if is used to dump in storage banks how fast can replenish what is taken. If a feedback is used to increase rate of replenish we are back to how it may perform under load ... this is all about in any type of such systems, at least this is my opinion and I reserve the right to be wrong.
Quote from: Classic on Jun 26, 2024, 04:46 AMIt all depends on how it will perform under load or if is used to dump in storage banks how fast can replenish what is taken. If a feedback is used to increase rate of replenish we are back to how it may perform under load ... this is all about in any type of such systems, at least this is my opinion and I reserve the right to be wrong.
I'm sure you are right. In any case I want to get it built and tested, then we might have some idea. I picked up my first print today - one half of the base. The other half should be ready tonight and then I have two or three more days of printing next week.
Hello Prajna,
Thanks for all explanation plus videos, yes, they do help a lot to understand your setup!!
What I find very interesting is the way you have been able to achieve a Constant Dual Reciprocating Movement, which is Self-Assisting plus Self Compensated.
The Action and Instant Reaction between all four magnets, just by a Smooth, non-frictional spin of a rotor, just on its own is a great achievement!!
I do not know if you are familiar with Lüling Magnet Motor...back on 1966, but here is a video that I uploaded from the original 35mm Film:
Lüling uses FIRST, a
Full Neutralization of Forces between magnets (please, realize at that time Neodymium Magnets were not discovered yet), using one end at an Attraction and the other end at Repulsion, both forces -if they are fully balanced- they will spin very smoothly.
Then He uses a Method* to unbalance the forces just on one end (either Attract or Repulse) therefore, releasing the FULL FORCES of the opposite side, which propels the main rotor.
I have worked before on this and it works, it is just that I decided to use the Repulsion side to unbalance...which resulted in requirement of great forces.
So, I used an Air Piston (Pneumatic System) to do this job...and the Magnetic Forces spin the rotor at over 400 RPM's:
Now looking at your Design Method*, I see an easier way, not requiring great forces, to "unbalance" the repulsion end, without the need to use Pneumatics!Of course, there are many possibilities here...as to also unbalance the Attract side, which I think it was what Lüling used.
If you would like to read more about my development, it is on Topic below:
LÜLING MAGNET MOTOR BY UFOPOLITICS (overunitymachines.com) (https://overunitymachines.com/index.php/topic,3.0/topicseen.html)
Regards
Ufopolitics
Quote from: Ufopolitics on Jun 26, 2024, 08:26 AMHello Prajna,
Thanks for all explanation plus videos, yes, they do help a lot to understand your setup!!
What I find very interesting is the way you have been able to achieve a Constant Dual Reciprocating Movement, which is Self-Assisting plus Self Compensated.
The Action and Instant Reaction between all four magnets, just by a Smooth, non-frictional spin of a rotor, just on its own is a great achievement!!
I do not know if you are familiar with Lüling Magnet Motor...back on 1966, but here is a video that I uploaded from the original 35mm Film:
Thanks @Ufopolitics, that looks interesting, I will certainly take a look, and thanks for uploading the videos.
What is good about my arrangement is that it makes the best of the inverse square law (1/r^²): when the finger moves out of the magnetic gap the magnets repell strongly because they are close and this assists to pull in the magnets that are spaced on the opposite side of the rotor, which as they approach the newly-introduced finger attract more strongly as the repulsive force of the separating magnets drops off. It is rather a neat arrangement. I'm off to watch the videos you posted and to read the pdf @Classic posted.
(1/r^2)
Quote from: Ufopolitics on Jun 26, 2024, 08:26 AM
Fantastic video and nice build, @Ufopolitics. That will be very interesting for me to explore once I'm done developing the SFT. I'm thinking we may be able to put the switching magnet (or magnets) on a synchronised rotor rather than move it directly away from the gap. That way we have simple, efficient rotary motion rather than reciprocating motion (I know I have reciprocating motion in my design too but that is just for this 'educational' configuration, I will move to a rotary configuration once I have finished and demonstrated this proof-of-concept).
Quote from: Prajna on Jun 26, 2024, 10:05 AMFantastic video and nice build, @Ufopolitics.
Thanks Prajna, I am glad you liked it!!
Quote from: Prajna on Jun 26, 2024, 10:05 AMThat will be very interesting for me to explore once I'm done developing the SFT. I'm thinking we may be able to put the switching magnet (or magnets) on a synchronised rotor rather than move it directly away from the gap.
Exactly!!...I am so glad, as I knew it was very easy for you to "see" and then "fuse" both applications into one...
Quote from: Prajna on Jun 26, 2024, 10:05 AMThat way we have simple, efficient rotary motion rather than reciprocating motion (I know I have reciprocating motion in my design too but that is just for this 'educational' configuration, I will move to a rotary configuration once I have finished and demonstrated this proof-of-concept).
Yes, "simple" after two open and capable minds "see" the possibilities...of two completely isolated devices, blend them together to bring a better and cleaner result.
I see exactly what you are seeing now, and described above...and, yes, it could be done!!
Take your time in your development, as it will be many tests required, to achieve a better performance as a better understanding of your excellent approach.
Regards
Ufopolitics
Well, I think all discovery is made by seeing what disparate things have in common.
I look forward to exploring this further with you.
Thank you.
A little update: I have finished printing the parts and now just have the rotor and a small bush to make. I was going to get my original rotor water jet cut but I have redesigned it so that it will be easy for me to make with the tools I have.parts.jpg
Well, the SFT-Mk5 is all assembled but sadly it is not rigid enough. I'm hoping that if I beef up the supports for the bellcranks that might make it stiff enough to work. The problem at the moment is that the magnets stick to the rotor and the mechanism is supposed to limit their travel so that can't happen but there is too much movement in the bellcrank mounts and that lets the magnets get too close to the rotor. Oh well, iterative process.
SMT-Mk5 Assy.png
You may want to use some plywood instead of plastic or just wood. For sliding rods, find and chop saw or anything that use sliding rods and adapt it.
Also, I can see your iron disc is not slotted as it should to switch magnetic flux.
For some frictionless you can use some superglue and graphite ... look up for "Lidmotor" youtube channel.
Quote from: Prajna on Jul 07, 2024, 10:36 AMWell, the SFT-Mk5 is all assembled but sadly it is not rigid enough. I'm hoping that if I beef up the supports for the bellcranks that might make it stiff enough to work. The problem at the moment is that the magnets stick to the rotor and the mechanism is supposed to limit their travel so that can't happen but there is too much movement in the bellcrank mounts and that lets the magnets get too close to the rotor. Oh well, iterative process.
SMT-Mk5 Assy.png
Hello Prajna,
Sorry about that!
But you do NOT need to make a Rotor that is a fully steel plate constructed.
You can make a thicker rotor in plastic, that can have stiffer and wider bearings and bolt on the metal strips to it.
Actually, a full steel rotor will deviate the magnetic fields where they are not supposed to expand to.
For sure a thin metal plate rotor would wobble under the magnetic attraction.
Cheers
Ufopolitics
Quote from: Ufopolitics on Jul 07, 2024, 02:10 PMHello Prajna,
Sorry about that!
But you do NOT need to make a Rotor that is a fully steel plate constructed.
You can make a thicker rotor in plastic, that can have stiffer and wider bearings and bolt on the metal strips to it.
Actually, a full steel rotor will deviate the magnetic fields where they are not supposed to expand to.
For sure a thin metal plate rotor would wobble under the magnetic attraction.
Cheers
Ufopolitics
Yes. In fact my first design was like that but I wanted easy construction with this model. It is just for testing the principle and to try different configurations of rotor. I imagine the rotor will develop considerably but for now the first priority is just to prove the principle.
regards,
Prajna
Just an update. I've just finished the design for Mk-7 (Mk-6 used gearing to sync the magnets and the 3D printer I have access to just isn't up to the accuracy required for printing gears that mesh well). I will be printing parts to test fit but the design requires bearings, which I have ordered but they won't arrive until the middle of August. I'll get this design up on my github soon in case anyone fancies to do a repo. Meanwhile I will be doing some calibrating on the printer to try to get it more accurate and I'll be working on Mk-8, which will be a combination of this principle and the Luling magnetic motor that @ufopolitics helpfully posted earlier in this thread.
SFT-Mk7 Cycles 2.png
So, while I wait for bits to build Mk7 I've been pondering designing a rotary machine based on switching flux using a ferromagnetic sheet between opposed poles, i.e based on this same principle.
Take a look at the following (very rough) sketch:
strack.png
Imagine two magnets with their poles opposed (the rectangles in the image), they are constrained to run in sinusoidal grooved tracks and in line with each other. When they are at point A they encounter a sheet of iron in the gap and will be attracted to it, imposing a vector force on the grooves, that are converging, making the track displace to the left (or the magnets will displace to the right.) When they get to point R there is no longer the iron sheet between them and they will repel, imposing an opposite vector force on the track, which is now diverging, and causing them to continue to displace the track to the left (or the magnets will displace to the right - either we constrain the track and the magnets move to the right or we constrain the magnets and the track will move to the left).
If this idea works on a linear basis then we can wrap that linear arrangement around a cylinder, producing rotary motion.
Thoughts?
So, I've progressed in my thinking and progressed from a switched flux transmission system, which requires an input that it might amplify to an output, to what might be a self-running switched flux magnetic motor. See what you think. Here's a model to present the idea:
description.png
What you're looking at is a cylinder with two opposed sinusoidal cam tracks running around the sides and slider rods that support carriages carrying a magnet and a bearing each. The carriages can slide up and down the slider rods and the bearings constrain the carriages to follow the cam tracks. The magnets are fitted in the carriages so that like poles are opposed on each pair of carriages. There are ferromagnetic tabs (soft iron or transformer laminations) arranged around the centre of the cylinder at each point where the opposite cam tracks are converging and gaps between the tabs wherever the tracks are diverging.
When the cylinder is rotated such that the magnets on one side are closest there is no iron in the gap between them, so the magnets repel, imposing a vector force on the cam tracks that causes the cylinder to rotate to the left. The magnets on the opposite side will be at their maximum separation but they also then encounter a tab in the gap and will be attracted to the tab rather than their fields opposing, thus imposing a vector force on the cam track that also causes the cylinder to rotate to the left (because now the tracks are converging.)
A further two sets of carriages should be arranged on the adjacent axes for smoother rotation and increased power, i.e. one set facing you and the other set at the back of the cylinder. There are five peaks in the sinewave of the cam tracks, so on either side of this image the magnets will be at opposite extremes of their travel, one set pushing and the other pulling. The front and rear sets of carriages will be in an intermediate position, still with one set pushing and the other pulling. The closest magnet pairs will exert the most force (due to the inverse square law) and there will always be one pair of magnets exerting a strong repulsion (or strong attraction.)
Hopefully that is enough info to describe the device.
Here's an update:
https://youtu.be/oqMJBSAOcMk
Progress is progressing: I now have the bearings I need and (I'm blown away) a friend gave me the money for the 3D printer I want, just it will take some time for the money to get to the bank and for the order to arrive, so I will soon be able to continue with construction. I will still need some magnets (this design calls for 8@ 10mm x 5mm N52 disc magnets) but I should be able to pick something like that from the China shop and I can always re-engineer things if I can't get that size.
Meanwhile I am working on the simulation, which will initially just animate the movement in the device but could be progressed to calculate force vectors and display them.
Here's a render (using Blender's Cycles render engine in FreeCAD) in case it entertains anyone:
Cycles4.png
And here's a simulation of it running:
Looking good 👍 maybe some graphite would help against friction on moving parts
Quote from: Classic on Aug 23, 2024, 08:29 AMLooking good 👍 maybe some graphite would help against friction on moving parts
Indeed, @Classic. I am looking for some linear slide bearings for the carriages but haven't found something suitable yet. Most linear bearings have a large footprint compared to the bore and are quite weighty. I'm using 5mm rod (probably hardened tool steel if I can find it at a reasonable price), so some linear bearings with a 5mm bore, maybe 10mm outside diameter and as short and light as possible would be suitable but I have not come across such a thing yet.
@Prajna, I don't want to discourage you and I like your easy going approach but as I said from beginning this type of setup require some skillset and pretty good toolset engineering workshop.
Your 5 mm steel rods might not be enough for a rigid build. More likely you'll need some steel pipe/tubes 20-30 mm external diameter with wall thickness 0.5- 1 mm or square steel tubes or similar with a pretty good honed surface for sliding ... following your approach you may want to look up for polished hanger bar for wardrobes but they need at least 3 points fixing at each end and a very good balance of the system not to be wobbly.
Although it may work with 5 mm steel rods as long as you use tension wire from the top to fix it diagonal to the surface where the machine will be placed (like a tent).
Have a look online for a sliding chopsaw and observe the sliding mechanism which suport the whole motor.
Take in consideration vibrations introduced in system and inertia in all moving parts.
Eventually you may think how to adapt some gas shock absorber used in auto industry for easy lift/close of bonnet/boot lid. Maybe a visit to an auto scrap yard may help to find more parts for your build.
I think @Lidmotor on youtube shows how to use some superglue and graphite (pencil) for very low friction ... but you need to find your way for sliding bars. And also, PLA from 3D printing can be hardened with superglue as well.
I like your dedication and conviction and I wish you good luck.
Thanks @Classic. I'm not sure you have realised the scale I'm working at - the whole device is about a six inch cube. My magnets are tiny, really, 10mm x 5mm disc magnets, so I'm not engineering for big forces and I won't be disappointed if it quickly spins up to a speed that results in its destruction. I want to prove the principle.
I thought superglue and graphite formed a super-strong super-glue, rather like baking soda and super-glue. If it lowers frictional resistance then that might well prove useful. Graphite anyway will help. Polished rods are available for 3D printers etc and tool steel (silver steel) is pretty good stuff because it is rolled to a very close tolerance. Linear bearings would be great, if I can find some that are suitable but graphite and maybe HDPE might work pretty well. Mild steel rod and PLA do not slide very well.
I may have a rather anachronistic approach to development but it seems to work for me, No matter how carefully you think things through there will remain some things that have been overlooked or unknown. A friend pointed out that the unknown is infinite and the known is finite and, no matter how much we learn, that will never change.
At the scale I'm working atm I think 5mm rods will be just fine and if I have to up the size for the next model or mitigate vibration and suchlike, well that is just part of prototyping. Maybe I could be more efficient or do a few engineering calculations before settling on a design but an alternative approach is to cast an engineering eye over the strength of forces you are dealing with and the distances over which they are operating and the materials and tools you have to hand and then you say, "Ok, 5mm rods will do as a first guess."
Thanks for the suggestions.
Also you may consider teflon spray coating for almost no friction ... but I have-no idea how long can last or if it is more efficient or cost wise compared with graphite for a proof of concept prototype.
I'm still awaiting delivery of a new 3D printer (said to be arriving on Wednesday.) Meanwhile I have been designing the Mk2 version that incorporates a control system.
I've updated the web page for the device detailing the control mechanism that allows the device to be started in forwards or reverse rotation and to be stopped when running. (Just in case anyone is interested.) I'm rather pleased with the way it has turned out and has fitted into the device and I think it is worthy of a patent by itself (if I was into patenting.)
The control system toggles the device off whether it is rotating forwards or backwards, is simple and has few moving parts.
Info at https://tomboy-pink.co.uk/sfmm/ (https://tomboy-pink.co.uk/sfmm/)
Well, well, well. Cambridge University's Naked Scientists forum just deleted a thread about my device after it had been running for perhaps two weeks. None of their 'naked' scientists wanted to look at the geometry and magnetic fields in the device, rather they just dismissed it and when I questioned their dogma they said they were not dogmatic, they were open minded and no scientific laws are certain, all are open to be disproved or improved with sufficient empirical evidence. And then they deleted the thread. Very open minded. Not.
I have seen this patern before on different forums, where such topics have been hidden from public eyes without any explanation, not even mentioning that is working or not ... maybe the same people
Well it turns out that they had not deleted the topic, just moved it to the 'speculative' section of the forum without telling me. Bad manners rather than bad faith. They are still not addressing particulars but rather taking the tack of "work it out yourself." The reasons for that are open to speculation too.
This is very kind of you to add the correction. Many thanks.
When I have been challenged about my theories I had to show up my working models, even if they are not yet the final product.
No problem, @Classic, I like to be fair. I have released all the information about my device and the history of how I got here. Anyone is free to clone my repo and build and test the device themselves.
While waiting for some filament...
https://tomboy-pink.co.uk/figuera/
Hello Prajna I have looked at your SFT design I am very acquainted with this technology
I tried you email address you put on your web page ( did not work for me )
unlike the Science / Physics people it the places of higher rejections ( that do not wish to respond - mostly because
they are missing knowledge on the subjects of being nice or kind - ( If I had a penny for every time ( I ) - would be richer than I am already, sorry for the true comments -- back to the subject ---
First - really nice job -
second - When North to north magnets are facing each other the magnetic attraction is 4 times pull force then using 1 magnet of north or south only to ferrous or iron based metals
The same amount of push away force the the north to north facing magnets produce is the same amount of attraction backward as the magnet pull away from the steel plates
magnet force depletes by the square of the distance so the pull in energy is very small when putting the block steel between the magnets / when the magnets are close together where they need to be to open / remove the block steel plate the magnets are at their closest point and highest pull force of attraction making the
( Action )energy output ( = or less ) than the output energy produced on that device ( because the pull back force is equal ) I have done many tests in different ways on this subject ( Magnetic Shielding )
If you wish I can help you design a new concept for that system that removes the pull back ( counter reaction force )
I already have a design that has been tested for that device ( I never built a motor to use the technology I am talking about ) but it does exist ( you will probably laugh when you see how easy it is to remove the pull back force )
leaving only The usable ( Action ) forward motion produce by the magnetic pushing apart ( in a motor design of course )
Thanks Dr. Wlazlak ( wlazlakt ( at ) gmail.com --- because your email address did not work -- prajna -
We should talk - I like your work --- Plus I have a fab-shop --
Quote from: Dr.Wlazlak on Jan 31, 2025, 03:10 AMHello Prajna I have looked at your SFT design I am very acquainted with this technology
I tried you email address you put on your web page ( did not work for me )
unlike the Science / Physics people it the places of higher rejections ( that do not wish to respond - mostly because
they are missing knowledge on the subjects of being nice or kind - ( If I had a penny for every time ( I ) - would be richer than I am already, sorry for the true comments -- back to the subject ---
First - really nice job -
second - When North to north magnets are facing each other the magnetic attraction is 4 times pull force then using 1 magnet of north or south only to ferrous or iron based metals
The same amount of push away force the the north to north facing magnets produce is the same amount of attraction backward as the magnet pull away from the steel plates
magnet force depletes by the square of the distance so the pull in energy is very small when putting the block steel between the magnets / when the magnets are close together where they need to be to open / remove the block steel plate the magnets are at their closest point and highest pull force of attraction making the
( Action )energy output ( = or less ) than the output energy produced on that device ( because the pull back force is equal ) I have done many tests in different ways on this subject ( Magnetic Shielding )
If you wish I can help you design a new concept for that system that removes the pull back ( counter reaction force )
I already have a design that has been tested for that device ( I never built a motor to use the technology I am talking about ) but it does exist ( you will probably laugh when you see how easy it is to remove the pull back force )
leaving only The usable ( Action ) forward motion produce by the magnetic pushing apart ( in a motor design of course )
Thanks Dr. Wlazlak ( wlazlakt ( at ) gmail.com --- because your email address did not work -- prajna -
We should talk - I like your work --- Plus I have a fab-shop --
I'm sorry the email didn't work. I am certainly interested in any geometry that might reduce the attraction of the tab back into the magnetic gap. You can post here or PM me. Thanks for persevering.