APL's DIY axial-flux motor

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APL   1 kW

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Re: APL's DIY axial-flux motor

Post by APL » Feb 12 2019 8:26pm

KD5ZXG

Ha! Well,..you got me there.. BUSTED!! :lol:

Hey, as long as were on the subject of Litz, and multi strand wire,.. whats your favorite method of removing enamel
from manet wire.? I'm going to have 20 strands x 21 magnets to solder. Need an easy way to tin them.

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Re: APL's DIY axial-flux motor

Post by KD5ZXG » Feb 13 2019 12:54am

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 remove legs of a through-hole device all at once.
Drop in replacement without need to clear the holes.

Sometimes to solder big connectors, or tin wires.
Things a soldering iron could not do in a reasonably
short time. Heat can travel to where it isn't helpful.
Contrary to reason, more heat sometimes burns less.

I suspect we fill the pot with pure tin only because
its cheap. Proper thing might be to add 2-4% silver.
Or maybe they just like to run it extra hot? I dunno.
No good for cold climates, can phase change to gray.
But gives a good shiny start. Blend with leaded or
silvered solder while the work is still hot and before
you forget.

https://www.youtube.com/watch?v=sXB83Heh3_c

A flow solder machine full of ROHS might also work.
Not as hot as pure tin volcano, but sometimes when
the volcano was dead cold and gonna take 30min to
warm up, I've abused the other machine to tin wires.

Final Thought (I've not tried) : Propane Torch

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Re: APL's DIY axial-flux motor

Post by larsb » Feb 15 2019 2:26am

I tried a molten NaOH salt bath on my phase wires with enamel that wouldn't come off. Cheap, effective but dangerous. One minute in the bath stripped wires totally clean and shiny 😃

Outside, gloves, eye protection, "disposable" clothes and no fumes breathing.
Ride on :D

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APL   1 kW

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Re: APL's DIY axial-flux motor

Post by APL » Feb 15 2019 2:12pm

Good information. That enamel is tough stuff! I wish I had a gallon of it. Better than any paint I've ever used.
I suppose they have a special way of prepping the copper before it's coated, and then it's probably baked on.

Iv'e used paint stripper before, and it works, but I don't like the toxicity, and you have to clean it well afterwards.
Plus,.. you have to wait.

I saw the video on cold tin, wow,.. I'm sure I've had some cars that were made out of that! :) Wish I would have
taken chemistry in school, one of the biggest mistakes I've made.

I've seen a small palm sized torch,(butane?),..otherwise, Iv'e got grandpas old 'big iron' that'll cook anything.
I'll see if I can make a little solder pot, like you said, and use flux. It would be nice to just dip it in, and be done.

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Re: APL's DIY axial-flux motor

Post by amberwolf » Feb 15 2019 9:56pm

APL wrote:
Feb 15 2019 2:12pm
I wish I had a gallon of it. Better than any paint I've ever used.
I suppose they have a special way of prepping the copper before it's coated, and then it's probably baked on.
It is baked on; a form of thermoplastic resin.

Here's a manufacturer
https://www.elantas.com/europe/products ... amels.html

An EPA datasheet
https://www3.epa.gov/ttnchie1/ap42/ch04 ... s02_2c.pdf

Here's a place that appears to sell one version of it in smaller quantities
https://www.parchem.com/chemical-suppli ... 93454.aspx
(there are various chemistries used, so you might ask them about which one you could use easiest for your applications).

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Re: APL's DIY axial-flux motor

Post by APL » Feb 16 2019 2:49pm

Great links to the 'real deal' enamel amberwolf. I know I've seen some varnishes for secondary coating's as well,
but I've never used any of it yet.

3M has their Scotchkote FD, I'm not sure of it's color. Otherwise there's Red insulating varnish spray, and sometimes
it's called 'secondary insulation'. But the most info I've found comes from an 'electrical varnish' search.

https://www.google.com/search?hl=en&biw ... 0c-7LOjiIA

Electrical varnish.jpg
Electrical varnish.jpg (8.74 KiB) Viewed 1250 times

Not as tough as the magnet wire primary coating though.

I've been trying to figure out how to keep these windings in place, width wise, and was thinking of coating them with
something like this, but I don't want to diminish the cooling, and I'd like to be able to take them apart again, so I'll
probably use string, or zip tie's, or small strip's of kapton tape. :?:

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Re: APL's DIY axial-flux motor

Post by APL » Feb 17 2019 1:49pm

Cores are all finished, and taped, and ready for windings. I'm working on a way to hold them while I do the winding.
Simple handheld side pieces that contain the wire to a specific area. Won't take much for twelve wraps.

Then I need some side insulation rings, to keep the wire insulated from the stator plate aluminum. Probably mylar.
Two 8" rings, with all the slots cut out.

While I'm doing that, Iv'e started on the axle and stator plate anodizing process. I want everything finished and ready
to go, so I won't have to take it back apart, once it's wired up.
( And I'm just 'dyeing' to try this out! :) )

The anodizing solution usually uses sulfuric acid, which I'm not really hot on using. After looking around I found an
alternative, sodium bisulfate medium. Listed as an irritant, and used in in pools and cleaners, it's much more friendly.

Heres a link to the process I'm using; http://www.observationsblog.com/science ... ttery-acid

Dye medium's.png
Dye medium's.png (364.23 KiB) Viewed 1225 times

They say it's an art, and I believe it, as the first attempt was a complete failure. :(
But I made the mistake of using a titanium wire for a anode battery connection. Wrong. The problem with anodizing
is that it's non conductive, so the titanium wire anodized first, and insulated itself from the part.
Aluminum wire is the cure.

I have high hopes for the next attempt,.. :oops:

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Re: APL's DIY axial-flux motor

Post by APL » Feb 20 2019 9:24pm

No love for old APL on this anodizing endeavor. :( I've been trying all week, and have had little success.

Theres a lot of variables with mixtures, temperatures, voltages, and current. Plus the dip times.
The sodium bisulfate mix is 16 grams powder to 160 grams distilled water, so just multiply that for whatever
is needed. I'm using a 12v SLA battery for a power supply at the moment,.. but have tried several power sources.

I have found that using aluminum foil for a cathode works well, and evens out the flow, plus, it's easy to use a
new piece for each test.

SLA & Alum Foil.jpg
SLA & Alum Foil.jpg (88.07 KiB) Viewed 1157 times

Bigest mistake I've been making is not letting the part anodize long enough, and I'm up to two hours at the moment.
They say a long slow process is better than a fast one. The part will have a yellowish tint to it when it's ready to go.

Another problem is that as the size of the part changes, so does the voltage, and current values needed.

I'm getting better at it, but still can't seam to get a dark color. I'm going to break down and try some sulfuric acid,
just to see if that could make the difference. I'm using Rit dye, which a lot of people use, and is a fabric dye.

Thing is, by the time you get the solution Ph mixed, it's relatively the same for both types of chemicals, it's just that
handling and storing the liquid sulfuric is worse than the sodium bisulfate crystals. They both need to be neutralized
with Baking Soda when they're discarded.

Test Part's.jpg
Test Part's.jpg (69.57 KiB) Viewed 1157 times

First part is anodized for one hour, then dipped in orange dye for 30 minutes, second part is anodized two hours, and
dipped. Stay tuned, I'll keep trying.

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Re: APL's DIY axial-flux motor

Post by APL » Feb 22 2019 8:45pm

The sodium bisulfate seem's to need a lot longer anodizing time. I put a stator plate in for 3 hours and it's working
much better. I switched over to a battery charger, because the larger parts will drain a small battery.
I used 2 amps for one hour, and 6 amps for two more hours.

Having a little trouble with a splotchy color though,.. I'll have to work on cleaning the parts better. I dip it in a
bath of a weak Lye solution for about 5 minutes, which helps , but I think it should be boiled in some Simple Green
before,.. or after.

Boiling in Rit..jpg
Boiling in Rit..jpg (69.55 KiB) Viewed 1105 times

Anyway, once it's anodized, I boil it in a Rit dye solution for about 20 minutes, and wala!,..she's a look'n good.
Now I have visions of doing chainrings, and bike parts! :)
A weak Lye solution will also remove any previous anodizing color from parts.

Anodized Stator.jpg
Anodized Stator.jpg (126.5 KiB) Viewed 1105 times

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Re: APL's DIY axial-flux motor

Post by madin88 » Feb 23 2019 4:07am

It looks awesome :thumb: Keep up the good work

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Re: APL's DIY axial-flux motor

Post by larsb » Feb 23 2019 6:57am

Looks like you could get 50% more copper in there? Better do it before you close the motor to save the extra work! When you're finished you'll be glad you got the extra 50% power out of it :D
Last edited by larsb on Feb 23 2019 4:54pm, edited 1 time in total.
Ride on :D

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Re: APL's DIY axial-flux motor

Post by SlowCo » Feb 23 2019 7:45am

8)
Looking good!
Hope all your hard work will pay off in the form of a great running motor.

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Re: APL's DIY axial-flux motor

Post by j bjork » Feb 23 2019 1:35pm

I can only say I am fascinated of what you are doing :wink:
It will be interesting to see the results.

I was looking in to anodize some aluminum parts a few years ago, but It never happened. But there was some companies selling the stuff to do a bunch of different colors. But I guess you already know all of this.

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Re: APL's DIY axial-flux motor

Post by APL » Feb 23 2019 9:47pm

Thanks for the thumbs up, it's nice to have a small moment of success, after all that I've been doing this week.

Once all the coils are in, I'll squeeze and compact the wire a bit, plus I'm getting better as I go,.. so the first ones
will probably get rewound.

Theres supposed to be some steel milled out of the sides of the cores, which would make the coils thinner and make
more room for air to flow through. Something I'll finish doing a little later.

The rotors will have spacers that are tilted like fan blades, that will force air around, and through the coils.

larsb, I'm a little unsure of your statement about 50% more copper. Do you mean a more even wind?

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Re: APL's DIY axial-flux motor

Post by larsb » Feb 24 2019 2:34am

The slots are supposed to be filled by all the copper you can get in there to reduce resistance losses. You seem to have wound parallell strands in bundles with gaps which lowers the fill substantially.

https://www.emetor.com/glossary/slot-fill-factor/

It is one of the most important factors of a motor build since copper losses normally dominate at high power.
Ride on :D

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Re: APL's DIY axial-flux motor

Post by madin88 » Feb 24 2019 3:44am

Along the outside there is some empty space and copper fill looks not good, but towards the center it is getting better and better. As the windings already seem to touch along the inside the fill should not be that bad, but with different winding wire and enough time you can improve this on almost every motor :)

What i wondered is if the shape of the coil cores is optimal, because axial flux motors usually have coils and magnets with trapezoidal shape (i guess in order to increase coverage) and on your motor not.
The other thing i now noticed is if the mangets spinning too close to the aluminum plates (the ones you anodized which are holding the cores), there will crop up additional eddy currents.
Image

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Re: APL's DIY axial-flux motor

Post by APL » Feb 24 2019 3:08pm

I see,.. well, the design does have some glaring flaws for sure, the result of not knowing enough in the beginning,
and some purposely done to make the first build easy to make, and prove the point of the concept.
IE, make it spin. :thumb:

The experimental model sets the stage for the next gen's, which we assume will have a grate number of improvements.

It should have trapezoidal cores, and magnets,.. but it's very difficult to make laminated stacks like that, and getting
the right size trapezoid magnets is just as hard to do. I originally had envisioned ferrite cores for that propose, which
would have made it much easier, but it didn't pan out.

Trapezoids make for a much smoother motor, but also add a lot of weight. The question is, is it worth it for a DIY?
I expect it to run a bit rough, but I've seen other motors that are just as bad, and seem to run OK.
Let's find out.

The whole propose of this build is to show that a person can make his own motor at home. Improvements are inevitable.
To me, the ability to make vast improvements is 'the' exciting part. How many other motors can we do that to?

I didn't realize how much weight the cores would be, and should have made them as short as possible, but I don't know
how short that is yet. It's something that I can still go back and do though. (width of the motor)

As far as the wire size strands and wraps,.. I'll stick with what I have for the first test, as I don't wish to deviate too
far from a typical DD motor. I'll try to get get the coils tighter to the cores, but geeze,.. how bad can it be?
It's a bar magnet for crying out loud. :)

The magnets will be spinning past the stator plates which would seem to be a set up for induction, I agree, but induction
is only really a problem with close proximity,..thousand's of an inch. Once you get a few millimeters away, it is vastly
reduced. There will be about 3mm clearance here. Plus, it's rpm related as well, and 300 to 600 rpm is really slow.

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Re: APL's DIY axial-flux motor

Post by larsb » Feb 24 2019 3:37pm

the switching coils affect the carrier plates, and it's the number of poles*rpm that decides the electric frequency.
It'll be interesting to see how hot it gets :flame:

As a concept study it's fine but these are hard limitations. You'll have to improve it in version 2 :D
Ride on :D

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Re: APL's DIY axial-flux motor

Post by Archer321 » Feb 24 2019 4:24pm

Every project I've ever undertaken always has come with a version 2 being planned by the halfway point.
Live and learn, and keep building.
:bigthumb:

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Re: APL's DIY axial-flux motor

Post by KD5ZXG » Feb 24 2019 9:45pm

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.

If that messes with mechanical strength, could sandwich two or more plates,
insulated from each other, but slotted to beak the loop in different locations.
Or perhaps jigsaw like a puzzle, and fill with epoxy, so a plate still interlocks
with itself. That might work in one layer, preserving some existing labor...

Shorted turns are only OK, even beneficial, for an alternator-like DC field coil.
As they pin DC flux and do not let it alternate. Forcing alternation elsewhere.
You should probably not put a shorted turn around any coil indented for AC.

Possibly jigsaw an S for better mechanical interlock than simple straight slots...
Attachments
slots.png
slots.png (386 KiB) Viewed 957 times

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Re: APL's DIY axial-flux motor

Post by madin88 » Feb 25 2019 6:36am

KD5ZXG wrote:
Feb 24 2019 9:45pm
Uh, wait. Am I just now understanding that your stator intends to alternate
and present the rotating fields? I should have realized earlier...

Shorted turns are only OK, even beneficial, for an alternator-like DC field coil.
As they pin DC flux and do not let it alternate. Forcing alternation elsewhere.
You should probably not put a shorted turn around any coil indented for AC.
I don't understand a single word. What do you mean with "shorted turn"?
APL wrote:
Feb 24 2019 3:08pm
It should have trapezoidal cores, and magnets,.. but it's very difficult to make laminated stacks like that, and getting
the right size trapezoid magnets is just as hard to do. I originally had envisioned ferrite cores for that propose, which
would have made it much easier, but it didn't pan out.

Trapezoids make for a much smoother motor, but also add a lot of weight. The question is, is it worth it for a DIY?
I expect it to run a bit rough, but I've seen other motors that are just as bad, and seem to run OK.
Let's find out.
More steel and magnet mass, togehter with the higher magnet coverage usually means MORE TORQUE.
I think a good compromize would be to use a few different, rectangular cores. Similar as here:
1.png
1.png (185.54 KiB) Viewed 932 times
2 (2).jpg
2 (2).jpg (144.11 KiB) Viewed 932 times
With the magnets you could do the same, or just order them in the shape you need which would not be that much more expensive as if you go with an off the shelf size.
I have bought already custom made magnets and if you like i can give you the contact to this company.
The magnets will be spinning past the stator plates which would seem to be a set up for induction, I agree, but induction
is only really a problem with close proximity,..thousand's of an inch. Once you get a few millimeters away, it is vastly
reduced. There will be about 3mm clearance here. Plus, it's rpm related as well, and 300 to 600 rpm is really slow.
Even if there is a gap of 3mm to the Aluminum, the field strength will be way to high to not have to worry about it.
Aluminum has way better electrical conductivity than steel which makes things even worse (the better the conductivity of the material over which the magnets are passing, the higher the eddy losses).
I am sorry that i have not recognized the problem earlier to give you a warning so that you could have changed the design or material.
You really should swap them out for glass fibre plates or another, non-conductive material, at least for the V2 then :)

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Re: APL's DIY axial-flux motor

Post by KD5ZXG » Feb 25 2019 7:48am

madin88 wrote:
Feb 25 2019 6:36am
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, it may not even spin.

Not to mention that coils and plates will overheat while doing
no useful work. Dead shorted = no point worrying about eddies.

Fix the big problem first, then maybe worry about small eddies.
Last edited by KD5ZXG on Feb 25 2019 8:35am, edited 1 time in total.

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Re: APL's DIY axial-flux motor

Post by madin88 » Feb 25 2019 8:29am

Ah you have absolutely right! The alu plates will act like a 1T winding with a short at the moment when the coils are put into the openings.
I missed that too and should have read your post more carefully.
Hm :shock:

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Re: APL's DIY axial-flux motor

Post by APL » Feb 25 2019 2:03pm

Now your saying I'm building a toaster? :lol: Sparks will fly, and flames will shoot out eh?
Maybe I can get on Mythbusters.

Your point is valid though, I hadn't thought about the 1T problem. I wonder how much of a real world problem
it might be. Well, this is an experiment,.. and I guess thats going to be another aspect of it. FSA.

I had thought about using phenolic, or glassboard, for the plate's, which would be the cure, but wasn't sure about the
strength overall. Mostly lateral., and the set screws will need a different system.
I'll keep it as a card up the sleeve for now, it wouldn't be that hard to do.

Calm down now! judgement day is coming, you may get your dance around the fire yet,.. and I will be banned to a
another section of this forum forever,.. never to be heard from again... :confused:
Last edited by APL on Feb 25 2019 3:19pm, edited 1 time in total.

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Re: APL's DIY axial-flux motor

Post by APL » Feb 25 2019 2:29pm

Also, I forgot to mention that I thought the segmented magnet Idea was a good one, and doing some cutting
would clean it up a bit. As a DIY guy, I tend to think 'off the shelf', but if you say custom made magnets are
not that expensive, then that would be a game changer.

I'm not sure about how the segmented core idea is supposed to work though,.. are they talking three sets of
laminations?

I've also seen hybrid lamination and ferrite combinations. So much headway to be made, we haven't even touched
tooth and core design yet, which is another world.

core design.jpg
core design.jpg (7.74 KiB) Viewed 886 times

Interesting stuff, thanks for showing it,.. food for thought for the next version, where trapezoid will be the
obvious choice.

First,.. get something to spin,..then, move on from there.

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