Introduction to the SFT

[Prajna]

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:



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.

[Prajna]

Here's an update:

https://youtu.be/oqMJBSAOcMk

[Prajna]

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:

[Prajna]

And here's a simulation of it running:

[Classic]

Looking good 👍 maybe some graphite would help against friction on moving parts