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  1. K

    APL's DIY axial-flux motor

    https://www.mag-inc.com/Media/Magnetics/File-Library/Product%20Literature/Powder%20Core%20Literature/XFlux-Tech-Bulletin-2016-EN.pdf Ferrosilicon pressed into a block or other shape. I dunno why silicon content was limited to 6.5%? Perhaps distributed gaps made more irrelevant? Basically...
  2. K

    APL's DIY axial-flux motor

    I grossly misunderstand how ferrite works, and could easily be in complete error: Trouble with saturating ferrite is that it may become either hard permanent or lossy supressor ferrite. Another reason to be cautious of it in a high torque motor. Only manganese oxide (in the presence of randomly...
  3. K

    APL's DIY axial-flux motor

    I'm also thinking Iron phosphate powder is only about 1/3 iron by weight. And who knows what those chemical bonds might do to the magnetism. Most forms of rust are hard lossy magnets. Iron Phosphate, soft or hard? Consider you started with pure iron powder, what ain't broke don't fix... Now...
  4. K

    APL's DIY axial-flux motor

    Perhaps, but also like high torque brushed AC motors, without brushes of course. Fields alternate several times faster than the rotor spins. I have to rebuild one of those soon anyway. Damn Craigslist table saw. Had no clue those were brushed till I plugged in and started throwing sparks.
  5. K

    APL's DIY axial-flux motor

    https://en.wikipedia.org/wiki/Electrodynamic_suspension Yeah, rings embedded in an insulating rotor repelled from high frequency coils. Higher frequency than rotation for efficient repulsion, but with modulated intensity that rotates in much the normal slow way. Except pushing rather than...
  6. K

    APL's DIY axial-flux motor

    What of repulsion instead of attraction? Drive high frequency AC to a sequence of coils to repel plates or rings in an otherwise insulating rotor. You've already some experience how much force eddies can create. Or perhaps a good old squirrel cage with variable frequency drive could somehow be...
  7. K

    APL's DIY axial-flux motor

    I don't know why you would machine back iron at an inconvenient angle. Lines will automagically detour to adjacent iron that isn't yet saturated. A problem that fixes itself, and perhaps not even a problem. Who cares if not evenly spread when less than saturated?
  8. K

    555 timer

    http://www.ti.com/lit/ds/symlink/lmc555.pdf Specs improved over the original version. 3MHz, 50mA. I'm not reading in depth so maybe missing something...
  9. K

    I "finished" my first 10s10p battery using vruzend 1.5 kit

    Might make better balance to blend mismatched cells to matched sums for each parallel group? You say matched series strings, but I can't figure how that alone guarantees parallel balance. I have no prior pack building experience, could be misunderstanding how that works. Got a 36V mid motor...
  10. K

    APL's DIY axial-flux motor

    Keep the plates and save your work. Just cut slots and shim with epoxy or other insulator. Not at the place where you have already tapped a set screw. Jigsaw an angle from one side (perhaps the clockwise side) of each stator to the outer edge. So you will still have one solid plate, but no...
  11. K

    Induction Motors ?

    Once was a thing called "repulsion motor" that ran as a squirrel cage induction motor. But had liftable brushes for extra low speed torque and starting. I don't understand how it worked. Was good enough for trains...
  12. K

    APL's DIY axial-flux motor

    Don't make the guts too inacessible. Huge stationary shorted turns remain about each end of the stator coils. Those shorts will eventually need to be jigsawed open before it works at reasonable RPM. You could still step with it at very low rate to measure torque. Near DC, shorted turns of the...
  13. K

    Why never see metal cast around wound stators?

    Inductor with shorted turn is a transformer or autotransformer depending where the short is. Primary then only presents leakage inductance. Current circulating in the short cancels what would otherwise appear as magnetizing inductance. By adding a short, the full amount of inductance you depend...
  14. K

    HyMag tech boosts magnetic flux density of permanent magnets by 10-30%

    Either type of magnet weighs more than iron. SmCo Gives a temperature advantage over NdFeB in return for brittleness and slightly weaker field. Yes, we can get rid of backing iron. Replace with cobalt, or add more heavy magnets to make an array that needs no backing, but not always helpful to...
  15. K

    HyMag tech boosts magnetic flux density of permanent magnets by 10-30%

    Monkey see monkey do. Lams are always safe. Properly placed dead shorts can work significantly better. Not impressed. AC induction motors work entirely on eddies and nothing else. What would be the performance of this motor without them? What I speak of is a solution that uses both PM and...
  16. K

    HyMag tech boosts magnetic flux density of permanent magnets by 10-30%

    Stator field leads the rotor field by some angle of course, but is not spinning quicker. Maybe you are thinking AC induction motor. Backiron eddies are helping. Lam those currents away, and permanent fields are more easily shoved out of the way. Giving less torque. Best you could do is plate...
  17. K

    HyMag tech boosts magnetic flux density of permanent magnets by 10-30%

    So, my suggestion of roller bearings in place of Maxon's brushes might not have been completely daft. Not sure how much current Bosch intends to push through these? Perhaps this illustration was just about bleeding some unwanted voltage that accumulates.
  18. K

    HyMag tech boosts magnetic flux density of permanent magnets by 10-30%

    Halbach is no magical replacement for backing iron. Nd2Fe14B is 72.3% Iron by weight. Twice as many magnets are then needed to form the array. So much for getting rid of iron... "Iron losses" aren't a problem in permanent magnets or their backing. Because a constant flux doesn't generate...
  19. K

    APL's DIY axial-flux motor

    Exactly which part of "shorted turn" did you not understand? Currents induced in the plates will oppose those of the coils. Flux cancelled by an equal and opposite magnetomotive force. If the surrounding circuit is not opened, it may not even spin. Not to mention that coils and plates will...
  20. K

    APL's DIY axial-flux motor

    Uh, wait. Am I just now understanding that your stator intends to alternate and present the rotating fields? I should have realized earlier... Eddies are the least of your problem. You need to do something about slotting those plates so they won't represent a shorted transformer secondary...
  21. K

    Why never see metal cast around wound stators?

    Eddy? Huge shorted transformer secondary more like it. Not recommended for stator with an alternating flux. Shorting ring (or bury in cast metal) might help a DC field coil or permanent magnet rotor that doesn't change flux. For fixed flux application, idea may not be entirely daft.
  22. K

    HyMag tech boosts magnetic flux density of permanent magnets by 10-30%

    https://www.electronicsweekly.com/news/research-news/rare-earth-free-magnet-made-from-cheap-materials-2016-05/ Its nothing new that various thin films can be made twice as powerful as bulk Neodymium Iron Boron. But the trouble is they are just thin films. Many rely upon strain, which cannot...
  23. K

    HyMag tech boosts magnetic flux density of permanent magnets by 10-30%

    https://www.anl.gov/article/stronger-lighter-greener Possible link to the original article? OP link roboplagiarized to the point of nonsense. I mean, "Neodymium" somehow changed to "Niobium"? Same things only completely different, nobody cares if we change a few facts...
  24. K

    APL's DIY axial-flux motor

    Dip end of Litz bundle with lots of flux in a pool of molten tin. Enamel will usually burn itself off, unless its not real enamel. Pure tin melts about 48C hotter than regular lead/tin solder. May be part of the magic when burning off enamel? Our pool is pumped more like a fountain or volcano...
  25. K

    APL's DIY axial-flux motor

    You post gold filled square copper wire and complain Litz costs too much?
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