Search found 87 matches

by KD5ZXG
Oct 02 2019 9:51pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 720
Views: 33189

Re: 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 JBWeld stee...
by KD5ZXG
Sep 30 2019 11:17pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 720
Views: 33189

Re: 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 orie...
by KD5ZXG
Sep 25 2019 1:39am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 720
Views: 33189

Re: 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, I've us...
by KD5ZXG
Sep 20 2019 7:47pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 720
Views: 33189

Re: APL's DIY axial-flux motor

Starting to sound like a squirel cage induction machine... 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 brush...
by KD5ZXG
Sep 19 2019 10:56pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 720
Views: 33189

Re: APL's DIY axial-flux motor

https://en.wikipedia.org/wiki/Electrodynamic_suspension KD5ZXG, I'm having trouble understanding what you said,..are you talking about something that uses aluminum rings that are repulsed from a Tesla coil type of concept? Or perhaps an aluminum disc with holes that is induction run, much like a pow...
by KD5ZXG
Sep 18 2019 8:11pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 720
Views: 33189

Re: 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 turne...
by KD5ZXG
Sep 09 2019 11:53pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 720
Views: 33189

Re: 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?
by KD5ZXG
May 17 2019 10:52pm
Forum: Motor Technology
Topic: 555 timer
Replies: 6
Views: 365

Re: 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...
by KD5ZXG
May 02 2019 3:30am
Forum: Battery Technology
Topic: I "finished" my first 10s10p battery using vruzend 1.5 kit
Replies: 2
Views: 289

Re: 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, and eno...
by KD5ZXG
Apr 25 2019 3:25pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 720
Views: 33189

Re: 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 shorted t...
by KD5ZXG
Mar 28 2019 7:19pm
Forum: Motor Technology
Topic: Induction Motors ?
Replies: 3
Views: 291

Re: 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...
by KD5ZXG
Mar 15 2019 11:25pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 720
Views: 33189

Re: 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 plates...
by KD5ZXG
Mar 04 2019 3:08am
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 70
Views: 3856

Re: Why never see metal cast around wound stators?

If an ac current were being fed through the coils at a fast enough frequency to produce eddy currents the iron teeth would be heating up especially as it’s feromagnetic and would be heating through hysteresis as well as Eddys. But they don’t heat through these and the frequency is not fast enough. ...
by KD5ZXG
Feb 28 2019 10:59pm
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 25
Views: 2047

Re: 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 do so....
by KD5ZXG
Feb 28 2019 10:17pm
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 25
Views: 2047

Re: 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? 793px-Rotterdam_Ahoy_Europort_2011_(14).JPG What I speak of is...
by KD5ZXG
Feb 27 2019 4:26pm
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 25
Views: 2047

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

In fact there will be eddy currents induced within magnets and back iron, because the rotating magnetic field from the stator is spinning quicker as the rotor itself (ERPM vs. RPM). Stator field leads the rotor field by some angle of course, but is not spinning quicker. Maybe you are thinking AC in...
by KD5ZXG
Feb 27 2019 5:34am
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 25
Views: 2047

Re: 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.
bosch.jpg
by KD5ZXG
Feb 26 2019 6:08pm
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 25
Views: 2047

Re: 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 eddies. If ...
by KD5ZXG
Feb 25 2019 7:48am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 720
Views: 33189

Re: APL's DIY axial-flux motor

I don't understand a single word. What do you mean with "shorted turn"? 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, ...
by KD5ZXG
Feb 24 2019 9:45pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 720
Views: 33189

Re: 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 winding. I...
by KD5ZXG
Feb 20 2019 9:21pm
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 70
Views: 3856

Re: 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.
by KD5ZXG
Feb 14 2019 11:20pm
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 25
Views: 2047

Re: 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 happen e...
by KD5ZXG
Feb 14 2019 7:47pm
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 25
Views: 2047

Re: 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...
by KD5ZXG
Feb 13 2019 12:54am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 720
Views: 33189

Re: 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. Can r...
by KD5ZXG
Feb 12 2019 7:47pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 720
Views: 33189

Re: APL's DIY axial-flux motor

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