APL's DIY axial-flux motor

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Re: APL's DIY axial-flux motor

Post by amberwolf » Jun 12 2019 11:17pm

APL wrote:
Jun 12 2019 9:06pm
OK. so then I finally checked for a short to the case, and sure enough ,.. it was shorted on all three. :oops:
If all three phases are actually shorted to the case, then they are also shorted to each other, and that could cause significant drag.

But it is probably only one of them, and the other shorts are thru the WYE connection point. (or delta if that's how you ahve it wired, I forget).

Disconnect *just* the point all phases connect to each other, then remeasure and you'll find which phase it is.

THen you can "break" that phase in half at one of the coils, and recheck.

Whichever half is still shorted, break taht in half, etc etc. andyou'll find which coil it is, to fix it.

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Re: APL's DIY axial-flux motor

Post by Lebowski » Jun 13 2019 1:49am

APL wrote:
Jun 12 2019 9:06pm
YG- .50v at 135rpm.
YB- .50v at 153rpm.
GB- .50v at 154rpm.
looks like the B phase generates less voltage than Y and G... (assuming star connected windings)

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Re: APL's DIY axial-flux motor

Post by APL » Jun 13 2019 2:24am

Yes, with the phase's all being connected on one end,(Y), and such low resistance, They would all appear
to be shorted, when in fact, it only takes one shorted wire to get that reading.

I'll have to break it down like you said. But if theres one, there are probably others. I suspect pinched
magnet wire. Anodizing is non conductive, so I find it hard to believe,.. but there it is...

With such a rats nest of wires in there, I may have a coil or two reversed,(even though I checked many times)
which would show up as uneven phase outputs as well. I'll give it all a good look again when I take it apart.

Is .50v at 150rpm what we expect?

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Re: APL's DIY axial-flux motor

Post by Lebowski » Jun 13 2019 4:44am

for which voltage to expect you'll have to go on the internet and search how much flux your magnets produce. then with the amount of winding you'll stand a chance of calculating it. Easier is to measure one coil (take motor apart, use thin wires to connect coil to outside world as no current is flowing anyway for just this voltage measurement)...

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Re: APL's DIY axial-flux motor

Post by APL » Jun 13 2019 1:11pm

Almost missed your post Dui,ni shuo de dui,.. thanks for the experimental suggestion. :thumb:

As far as cutting the plates, there has been some previous discussion about it back around
page 11 or so. It keeps coming up, but the current plan is to cut an 'L' in the side of the slot,
and place a non ferrous pin into a hole drilled in the cut, as a lock of sorts.

Not sure how that will work in reality, but there are a few other ways. Kind of a bandaid, but
would give the needed information.
Heres a quick sketch.

Stator Cut..jpg
Stator Cut..jpg (40.6 KiB) Viewed 926 times
If I had enough room, a simpler way might be like this.

Stator Cut 2.jpg
Stator Cut 2.jpg (34.03 KiB) Viewed 923 times

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Re: APL's DIY axial-flux motor

Post by stan.distortion » Jun 13 2019 3:09pm

That thing looks the business, congrats :) What's the issue with cutting the plates? Read through from about page 11 but don't recall seeing anything. For the windings, could you energise each phase with a couple of volts and check the magnetic polarity at each core?

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Re: APL's DIY axial-flux motor

Post by Dui, ni shuo de dui » Jun 13 2019 9:31pm

APL wrote:
Jun 13 2019 1:11pm

As far as cutting the plates, there has been some previous discussion about it back around
page 11 or so. It keeps coming up, but the current plan is to cut an 'L' in the side of the slot,
and place a non ferrous pin into a hole drilled in the cut, as a lock of sorts.
The second solution seem like a good one to me, clever.

BTW, it is likely that the short you currently have goes in contact with the aluminum through this little set screw. Anodizing is insulating (though not very reliable), but there's a good chance that the threads scratched the anodized layer and that you get contact through them.
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Re: APL's DIY axial-flux motor

Post by fechter » Jun 13 2019 11:58pm

Maybe cut diagonally from the corner of the hole. The set screw will still hold the coil.
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Re: APL's DIY axial-flux motor

Post by madin88 » Jun 14 2019 1:56am

I would cut it here (red line) simply because it is easier to do as cutting it L-shaped.
If you fill a drop of epoxy (liquid steel) into the gaps it should be plenty for stability in my opinion.
Stator Cut..jpg
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Re: APL's DIY axial-flux motor

Post by APL » Jun 14 2019 1:50pm

The straight cut would probably work fine, although a slant cut would provide a little more support?
Maybe a thin piece of glassboard, or plastic, and epoxy in the slot.
Many simple ways to do it at any rate.
Slany Cut 2.jpg
Slany Cut 2.jpg (33.58 KiB) Viewed 842 times
Works out in a picture,.. but in reality things are a bit smaller, so I'll have to wait and see how the
actual's play out. Plans are often foiled by reality. :roll:

It's supposed to rain the next few days, so I'll get this motor torn apart, and we'll see what kind of
problems it really has with the wiring.

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Re: APL's DIY axial-flux motor

Post by fechter » Jun 14 2019 3:50pm

I think a single cut will be fine. There isn't much stress on that area. Most of the force is sideways. Epoxy in the cut is a good idea.
"One test is worth a thousand opinions"

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Re: APL's DIY axial-flux motor

Post by Archer321 » Jun 14 2019 8:37pm

APL wrote:
Jun 14 2019 1:50pm
Plans are often foiled by reality.
That is an excellent quote.
I think I'll steal it.

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Re: APL's DIY axial-flux motor

Post by APL » Jun 15 2019 7:32pm

It finally dawned on me that I can just use a large puller to take the rotors off. Doesn't leave a mark
and comes off with out a wrench, just using my hand to turn it was enough. Very nice!
Rotor Puller..jpg
Rotor Puller..jpg (123.39 KiB) Viewed 788 times
After I got it apart, I desoldered all the connections, and measured each coil. Three were shorted.
5 - 13 - and 17. So, two of the three phases were shorted, blue and green, which is just what the AC
test showed.

Not by much though, just a little nick in the enamel on the inner windings is all it took. And only on
one or two wires. The set screws ground the cores to the stator.
Hard to see in this picture,.. it's by the 'mA'.
Small Short..jpg
Small Short..jpg (110.99 KiB) Viewed 788 times
I have a layer of fiberglass around the core just to keep that from happening, but I let the coils spread
out to much, and thats all it took.
Core insultion..jpg
Core insultion..jpg (66.93 KiB) Viewed 788 times
I'll rewind those three coils, and make sure there are no more shorts before I button it up again.
I'm trying to decide if I should go ahead and cut the plates now, or give it another try 'as is' first.
I'm also tempted to rewind in 14 awg, and wire in straight series, but I can wait on that,.. baby steps.

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Re: APL's DIY axial-flux motor

Post by Lebowski » Jun 16 2019 12:18am

Are you sure you cannot rotate the one rotor plate, and measure the AC voltage of the individual windings when you do so ? This is a good test for each coil and for your coil interconnections.

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Re: APL's DIY axial-flux motor

Post by APL » Jun 16 2019 12:32pm

I can try to do that,.. I think I can reverse one rotor plate, but will have to assemble the motor, to spin it.
The rotors are not supported by themselves.

It will take a bit of effort, but I'll give it a shot. I might as well get readings for a single, and both rotors.
Good information to have for the record, and will help serve as baseline info. for future windings as well.

Another experiment I plan on doing, is hooking one rotor to a drill, and spinning it over a piece of plate
aluminum, to see just how much drag I can feel, and take some temperature readings before and after.

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Re: APL's DIY axial-flux motor

Post by Dui, ni shuo de dui » Jun 17 2019 12:45am

While your motor is still opened, take a little time to make sure your magnets fields are correctly oriented, just in case.
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Re: APL's DIY axial-flux motor

Post by APL » Jun 20 2019 7:14pm

Well, it makes for a good photo at least. Maybe I can sell it as art. :)

Stator Flower..jpg
Stator Flower..jpg (101.72 KiB) Viewed 623 times

After fixing the three coil shorts, I finally got it all wired up for the test, and put the stator back together,
Went to check the ground wire for shorts,.. and still have one! :evil: Grrrrr!

I seems that when I apply pressure from the two stator plates, I get windings contacting the cores.

I'l keep working on it, but I've decided to order up some 14 awg wire and rewind the coils. I can hold the
coil shape and size much more easily, and it won't be so prone to pinches.

Plus, I discovered that the red and green Temco wire enamel is inferior to the amber color. Which might help
against abrasions.

https://www.youtube.com/watch?v=zxd6H8v44sU

Live and learn,..we'll keep trying.

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Re: APL's DIY axial-flux motor

Post by thundercamel » Jun 21 2019 8:32am

APL wrote:
Jun 20 2019 7:14pm
Well, it makes for a good photo at least. Maybe I can sell it as art. :)


Stator Flower..jpg
Reminds me of this:
Image
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Re: APL's DIY axial-flux motor

Post by APL » Jun 21 2019 7:51pm

I absolutely cannot figure out what that is,.. but it looks a lot like some of the dreams I've had lately. :confused:

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Re: APL's DIY axial-flux motor

Post by thundercamel » Jun 21 2019 10:37pm

It is a model of what's left of the reactor number 4 at Chernobyl. The upper biological shield had 1884 channels through it for fuel and control rods, weighed 1000 tons, and was blown far enough upwards to damage the roof of the reactor hall before landing at
a 15 degree angle on top of the reactor core. I've been watching the series the last few days, and it's pretty freaky.

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Re: APL's DIY axial-flux motor

Post by APL » Jun 22 2019 11:59am

I've seen other shows on the matter, but the model really helps explain what happened. 30 years
later and it's still just as sad and tragic. A monument to what humans can achieve,.. in many ways,
both good and bad.

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Re: APL's DIY axial-flux motor

Post by APL » Jun 24 2019 8:04pm

I had the idea of twisting the 10 strand coil wires, to try to keep them from spreading out after winding,
which seemed to work somewhat. But still tends to spread out at the corners of the winds, and insists
on being a double layer wind.

Twisted.jpg
Twisted.jpg (97.31 KiB) Viewed 461 times

So then I stripped off some 14 awg, and tried an experimental wind with that,.. I got up to 11 turns on
one pass. Nice and tight and flat single wind. Looks good to me, with no chance of small wires shorting out.
Much more compact than multi-strand. Although it's one turn less. I can live with that for now.

14 AWG.jpg
14 AWG.jpg (91.4 KiB) Viewed 461 times

So I think thats the way I'll go, and we'll see if the output numbers are the same, or close to the multi strand.
I'll run a test on a single coil of each, to get an idea of any difference.

I'll order the wire out, but next week is scheduled for a trip, so it will be a while before I can get back on track.
Such as it is, but I have a good feeling about this re-wire. :)

I'll get a multi-strand single coil output, so we'll have at least one coil reading,.. and try to get the magnet/
aluminum spin test done.

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Re: APL's DIY axial-flux motor

Post by APL » Jul 09 2019 7:32pm

You were right,.. there is a lot of drag on the aluminum when I spin the rotor with the drill.
26 magnets makes a big difference, and even at 10mm away it will start to drag the drill down.

At 5mm it will have enough power to spin the test piece of aluminum below it, and at 1mm
the drill will have a hard time turning it.

I hate it when I'm wrong.

So, new stator plates made out of glass board are a 'must' in the future. But I don't think it's going
to keep this motor from working,.. it's not going to be near as efficient, but it should still spin.
At least enough for a test.

It doesn't help that I crushed the bearing seal when I made the adapter for the drill, and need a
new bearing. But the good news is that after looking closely at the bearing cap, I noticed that
it was rubbing in the center, which is one reason why the rotors were turning so hard. (I think)

Whoops.
Seal crush.jpg
Seal crush.jpg (74.94 KiB) Viewed 166 times
Rub mark in the center of the cap
Bearing rub..jpg
Bearing rub..jpg (77.4 KiB) Viewed 166 times

I have the new wire for the cores, and when I get the new bearing, I can get some test results for
the different coil configurations,.. fix the rub on the cap, and move forward with rewinding all
the coils.

Two steps back, one step forward. :)

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Re: APL's DIY axial-flux motor

Post by larsb » Jul 10 2019 2:25am

At 5mm it will have enough power to spin the test piece of aluminum below it, and at 1mm
the drill will have a hard time turning it.
What's the available torque on your drill?
If it's a drill press then i think you need to do a sanity check if you should put more effort into the motor in this configuration. Drills are geared down to be quite strong, motor might not work at all.
Ride on :D

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Re: APL's DIY axial-flux motor

Post by APL » Jul 10 2019 7:22pm

No need to do a sanity check, I'm pretty sure I'm nuts. It's OK though, because most everybody els is too. :)

Not a drill press, I wanted to use a hand drill so I could get a feel for it. Not a wimpy drill, but not a brute either.
I should have specified that the 'spinning part' was a stator plate, with a 5mm spacer in between. Not very heavy.
The 'close' test was a 1/2" piece of plate aluminum,.. and that has an amazing amount of resistance!
Spin test.jpg
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5mm spin test.jpg
5mm spin test.jpg (90.26 KiB) Viewed 97 times
Not the most scientific test's, but it gave me a feel for what kind of forces were at work, and I came out of it with
a pretty good idea of what to expect.

It's an experimental motor,.. not a prototype. In the experimental stage, we generally plod along taking notes of
all the things to change, but do whatever it takes to get to the end result, which is a working model, or proof of
concept.

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