Introduction to the SFT

[Prajna]

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:



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

[Ufopolitics]

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:

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.

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.

[Classic]

@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

[Ufopolitics]

@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...

Cheers

Ufopolitics

[Prajna]

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:

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.

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