APL's DIY axial-flux motor

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larsb   1 MW

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Re: APL's DIY axial-flux motor

Post by larsb » Mar 09 2019 2:52am

:bigthumb:

Must say that everyone doing a motor build earns the credit! Interesting to see how this one turns out :D
Ride on!

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Mar 12 2019 12:37pm

Thanks larsb, certainly more work than I had thought, but mostly because it's the first,.. if I were to do it again,
things would go smoother. Defiantly learning a lot with this build.

So many little mistakes, in the end they all add up,.. I'll be lucky if it doesn't shake itself to death! One big problem
I'm having is that if I take a part out of the lathe, and then put it back in, it's not exactly in the same place as it was.
This little lathe is falling a tad short for something like this, but a lot of it is just me.

Still working on rotors and rings, lots of machining, but almost done. Can't really finish them until the bearing caps
and rotor spacers are done, since they all go together.

Think I might have figured out a way to turn it into a spoked hub motor though, by machining a flange on each bearing
cap, and drilling spoke holes in them, it would be like the Bionx D. Hmm,.. possibly. Might have to skinny it up a bit.

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Mar 12 2019 8:17pm

Finally got enough machining done to do a test fit, and see where I'm at with things. Definitely wider than I
wanted. It's about 2-1/4" wide now, and I see lots of things I could do to make it thinner. But for now, I'm just
going to continue to finish it up, and give it some juice. :bolt: :bolt: :bolt:
Rotor spacing.jpg
Rotor spacing.jpg (111.79 KiB) Viewed 1983 times
Rotor bearing.jpg
Rotor bearing.jpg (95.73 KiB) Viewed 1983 times
Up next are the bearing caps, and spacers between the rotors, which also act as a cooling fan. I should order up
some glue for the magnets, since that's coming up pretty soon.

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Mar 15 2019 8:53pm

Started on some spacers, I have my fingers crossed on how they will look. I decided to try a large diameter scoop
cut that will direct air onto the center of the coils, in either direction of rotation.
Spacers.jpg
Spacers.jpg (64.58 KiB) Viewed 1909 times
Not the original plan, butI'll give it a try. I can always make more.

Rotor spacers.jpg
Rotor spacers.jpg (86.97 KiB) Viewed 1909 times
They'll be milled down quite a bit on each side, at least 5mm,.. something I'll have to sneak up on, because it will
determine the 1 mm air gaps on each side of the cores as well.
The outsides of the spacers are flat now, but will get turned round, to match the curve of the rotors.

I was also able to put in some central vent holes, and turn a slight relief onto the outsides of the rotors.

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Re: APL's DIY axial-flux motor

Post by KD5ZXG » Mar 15 2019 11:25pm

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 might not entirely stop it from spinning. I would expect a shorted load and hard magnetic braking on attempt to spin fast though.

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Mar 16 2019 12:55pm

It won't be very hard to take this motor apart,.. it doesn't have the radial motor's dreaded 'stator suck' that makes
them such a pain in the ass to get apart. The rotors will have threaded holes for bolts around the diameter, and
I can just 'screw' the magnet array apart, and back together.

I know what your saying about the shorted turns, and it may be a problem,.. we'll just have to wait and see. I can
cut the slots, like you say, for a quick fix. Or make some new ones using your laminated plate idea. At the moment,
I'm leaning towards some composite stator plates, G10, FR4, Garolite, Micarta, etc., but I will need a good way to
secure the cores, and keep the air gaps. ( I've been giving it a lot of thought)

I feel that the voltage (40v), and the RPM that I'm using are fairly low, and the problem you are stating is usually a
high power-high voltage issue, but of course, I've been wrong before.

As Archer321 says,.. it's common to get half way through V1, and already be planning for V2.
The primary goal of this experimental build, is still just to get it to work. After that, I might do some redesigning.

One thing that has been on my mind as of late, is that on a mid drive motor, there is not really any need for so many
slots and poles as a rear hub motor.
The motor turns three times faster than a DD motor, so it only needs a third as many coils/poles to be just as smooth.
Theres a lot of wasted construction on this motor, as a mid drive.

If I should do it again, I would probably go with something very common, like a 9/12 pole count motor, and just make
everything larger.

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Mar 19 2019 8:07pm

Spacers are taking a lot of time, but are finally starting to come around. Tight tolerances, and just trying to find
a 'look' that I can live with, is a slow process.

Spacers.jpg
Spacers.jpg (92.58 KiB) Viewed 1802 times
I have them set for 1mm air gaps on each side, but thats just a guess at a place to start. Doesn't seem to be a lot
of solid info. on the net on the subject, as every motor is different. So I'll just have to try it and see what happens.
I could probably get down to .5mm if I can get all the cores in line, so theres lot's of experimenting to do on that.
Depends on how much wobble I'm going to have with the stator assembly.
Motor together.jpg
Motor together.jpg (79.69 KiB) Viewed 1802 times
Once I get the spacers drilled and taped, I'll be ready to make the bearing caps,.. and then it's getting dangerously
close to being done!
Some anodizing, glue the magnets, and the final stator wiring, and I'll be staring at a test run. :shock:

I'll have to start thinking about making a test stand for it.

larsb   1 MW

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Re: APL's DIY axial-flux motor

Post by larsb » Mar 20 2019 10:18am

You know, always when you think a project is close to the end then you realise it's actually 50% left :D :D
Ride on!

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Mar 20 2019 12:37pm

Yes, so true larsb,.. I hope it goes smoothly, but it will probably drag me through the usual briar patch of problems.
Sure hope not.

Plus, if and when it does work, I want to put it on my bike and ride it for a while this summer, to see what it can do.
After that, I'd like to tear it down and try to shorten the cores, lighten things up, and rewind it with 14awg wire.

As it sits, it comes in at just over 13lbs. I think I can loose at least 2lbs,.. but people on diets always say that. :)

So, yea, 90% done and 50% left....

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Re: APL's DIY axial-flux motor

Post by amberwolf » Mar 20 2019 5:57pm

In that picture of it on the table, it reminds me of some of the buildings in the Jetsons. ;)

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Mar 21 2019 12:36pm

I was hoping nobody would notice, but yea, thats where the design came from,...

I can't slip anything past you guys on the ES! :confused:
Jetsons buildings.jpg
Jetsons buildings.jpg (26.14 KiB) Viewed 1697 times

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Mar 22 2019 8:07pm

A little more progress,.. getting started on the caps. Slicing off a piece of 3.5" aluminum bar, makes me glad I bought the
band saw.
Cap cut.jpg
Cap cut.jpg (123.91 KiB) Viewed 1659 times
After some lathe work, the drive cap is ready for mounting screws. It locates off the bearing on the bottom side. A nice
thing about the cap is that it can be machined for any drive system, whether it be a freewheel, single speed, or belt drive.
Maybe add a flange and spoke it up,.. plus dial in the spacing as well.

Drive cap..jpg
Drive cap..jpg (87.67 KiB) Viewed 1659 times
This one will just be tapped for a threaded adapter, to power the cruiser.

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parabellum   10 MW

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Re: APL's DIY axial-flux motor

Post by parabellum » Mar 23 2019 3:18pm

Nice project!
cut that will direct air onto the center of the coils, in either direction of rotation
Do you think they will work that way? Maybe more like centrifugal fan, despite the scoops?

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Mar 23 2019 8:08pm

No, I'm not exactly sure how they are going to work. Theres not a lot of room, (1/2"), for some kind of fan set up.
I don't really want anything to 'stick out' very much, it's already a tight fit for my bike.

I wanted long/wide enough spacers to transfer toque between the rotors, and this seems like a good place to start.
( as opposed to just squirrel cage slats)

I figure either way, there should be 'some' kind of air movement around the coils,.. a lot more than a standard DD
motor. But as far as getting a specific, or correct flow pattern going,.. that will take some experimentation.
I don't know that much about fan tech.

I do wonder whether air should be pulled out, or of pushed in, though.
I figure, once it gets spinning, I can use some smoke to try and see what kind of flow is going on.

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Mar 26 2019 8:23pm

Finished up the rotors and caps, except for the back iron mounting holes, which will need a lot of alignment,
so I'll have to wait for the magnets to get bonded first.
The two ring sides of magnets mirror each other,..one side is north, and the other south.

I have the 3M - DP420 glue, and a buddy just happened to have an applicator gun that will work, so I'm all set to
start bonding. I just have to figure out how to space them and hold them yet. 26 per side.
If I had to buy a kit,.. the glue, gun, and the tips, it would run over $70., just to glue some magnets!
Rotors done..jpg
Rotors done..jpg (89.5 KiB) Viewed 1545 times
The good news is I can start anodizing the rotors, caps, and spacers! My favorite part. :)

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Re: APL's DIY axial-flux motor

Post by qwerkus » Mar 28 2019 5:01pm

This is just awesome. Good ideas, good craftsmanship. Keep it up!

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Mar 29 2019 7:51pm

Thanks qwerkus, it's getting close. :thumb:

Finished up some more anodizing, but I think it took a turn for the worse. :x

Funny how things in your head look better than they turn out.
I live in Wisconsin,.. and those are 'Packer colors', but thats not what I intended! The green is a bit ugly, and the gold is
a little too much.
Oh well, it is what it is. I might change something yet.
Anodized rotors..jpg
Anodized rotors..jpg (117.51 KiB) Viewed 1466 times
Moving on to the magnets, I cut out a pattern from some foam board, and plan to apply some wax to it somehow, so I can
get a couple of uses out of it, without having to peel it off the rings.
I'm hopping I can space it up a few millimeters, away from the glue, as well.
Bonding cutouts..jpg
Bonding cutouts..jpg (77.86 KiB) Viewed 1466 times

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Re: APL's DIY axial-flux motor

Post by qwerkus » Mar 30 2019 7:26am

APL wrote:
Mar 29 2019 7:51pm
Thanks qwerkus, it's getting close. :thumb:

Finished up some more anodizing, but I think it took a turn for the worse. :x
Yeah anodizing is more miss than hits. The internet is just filled with post of angry hipster who shipped in their belove fixie frame for anodizing, and got angry over the weird color result. Motorcycle guys here usually go black or transparent/polish finish - those are pretty safe options: first one "hides" all imperfection; second one matches best the natural oxidation layer of aluminium.

That beeing said, your color results are quite interesting. The problem is probably not so much the motor than the frame: you just have the wrong frame for this color :D For an instance, it would perfectly fit any of the psychedelic corratec frames from the late 90s...

Image

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Mar 30 2019 9:48pm

Ha! So true, I just have to repaint my frame to match! It reminds me of the 'dread' Chris King headsets,.. every
part a different color.
This is going to stick out like a sore thumb, I might have to get the black rattle can out... :wink:

Well, mostly wanted to show that it 'can' be done, in any color a person wants, however, it's an acquired skill, and
a little hard to control. I've been thinking more about clear anodizing, like you said,.. a bit easier to do.

I think I'm going to change the caps to orange, just to show how it's done,.. hope I don't mess that all up! :)

Won't make the motor spin any different though, colors are just silly human stuff.

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Apr 01 2019 12:49pm

A buddy sent me this link today,.. thought I'd pass it along. If you get time, check it out. It's all about wires and
connectors, insulation, auto, motorsport, aircraft, and has lots of videos, and other links. :thumb:

https://www.rbracing-rsr.com/wiring_ecu.html

Some of the pictures didn't show on my PC, but maybe yours is better.

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MJSfoto1956   10 kW

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Re: APL's DIY axial-flux motor

Post by MJSfoto1956 » Apr 01 2019 1:44pm

APL wrote:
Apr 01 2019 12:49pm
A buddy sent me this link today,.. thought I'd pass it along. If you get time, check it out. It's all about wires and
connectors, insulation, auto, motorsport, aircraft, and has lots of videos, and other links. :thumb:

https://www.rbracing-rsr.com/wiring_ecu.html
That's a great resource. Bookmarked.
Voting has ended: viewtopic.php?f=26&t=102697

Слишком мало, слишком поздно

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Apr 04 2019 7:22pm

Well, I was hoping to have the magnets bonded by this time, but Spring is in the air here, and I've been busy with
picking up winters mess out in the yard.

I did manage to get the foam board waxed though. I heated up some paraffin wax in a hot plate, and dipped the
board into it, and it absorbed the wax really well!
I think it will be impervious to glue now,.. but you know how that goes. We'll soon find out.
Wax & Foam board..jpg
Wax & Foam board..jpg (116.03 KiB) Viewed 1300 times
As far as motor colors go, I found some adhesive vinyl I had from another project, and applied that to the relief to
see what it would look like. I think it toned it down quite a bit, so maybe I'll just paint that section, and call it good.
Black accent.jpg
Black accent.jpg (110.21 KiB) Viewed 1300 times
I also picked up a cheap soldering pot on the Bay for about $25., and I hope it last's long enough to do all the stator
windings. If it works, it will make stripping the enamel off all the magnet wires a LOT easier. :)
Solder pot.jpg
Solder pot.jpg (101.56 KiB) Viewed 1300 times

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Re: APL's DIY axial-flux motor

Post by wturber » Apr 05 2019 3:56pm

I'd consider going full black on that area where you placed the vinyl. Go full "bumble bee" in the color scheme and call it the Axial-B.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
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Re: APL's DIY axial-flux motor

Post by amberwolf » Apr 05 2019 11:08pm

Or the Ostral-B, if you don't mind everyone going all bug-eyed and heretical.

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APL   10 kW

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Re: APL's DIY axial-flux motor

Post by APL » Apr 08 2019 12:58pm

Too much drama the last few days, seems like everything is getting in the way of this project.

I had to look up 'Ostral',.. and still don't know what it means. :oops: But it looks Spanish, so maybe a religious thing?
Reminds me of Orested though, a measurement of magnetism,.. Orested-B? :)

I'm busy sanding the surfaces of all these magnets at the moment, another tedious job,.. and they snap in half like twigs,
if you happen to fumble one.

I've been racking my brain on how to mark them north and south, so I can keep things straight while bonding. Didn't want
to line them up on a table, because they could all jump together and break.

Then I realized that if I leave them all stacked together, they are the safest, and just flip over every other one.
Only have 20 minutes, so I need to figure out the fastest way to do it.

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