Homemade Axial flux PM motor

[enrengineering]

Sorry for not posting the last week, I've been busy with exams.
Before the exams I shrunk the design and remade the rotor, I've printed two stators, one wound like the bavaria scheme AaBbCc (12 coils and 10 magnets) and the other one wound like ABCABC, none of them worked.

I went back to the 36 coil OG design and remade completely the stator. Here's the stator after printing:

The 6 inside tabs are for attaching a plate with a bearing embedded to it (I also changed the bearings to smaller ones) on each side,

the two outer tabs are for mounting the motor to test it. I increased the number of turns per coil to 10 and connected it in star.
Here's the stator fully wound:

I temporarily assembled the whole thing using only three screws to hold the bearing plates and then slid the same axle that V1 used. I was very nervous, I connected it to the cheap aliexpress bldc board and... IT WORKS!! I have to give it a gentle push and it starts up, I measured the current, about 0.3 amps (power supply) at full speed ∼1200rpm @12V, all the windings are cold to the touch with this setup. You can see it in action here:
https://youtu.be/2NKh9ckicXU
Following improvements to do this easter holidays:
-Machine an iron plate to replace the aluminum one
-Machine custom stainless axle with the flange at the end
-Improvise a jig for balancing the rotating assembly
I got in touch with a 3d metal printing company in my country, I asked them if they had a high magnetic permeability material, they have this ones available:
AlSi10Mg / A13600 / 3.2381 aluminum
316L / S31673 / 1.4404 stainless
18Ni300 / K93120 / 1.2709 they call it hard steel (I think this would be the chosen, but I think it would create more heat)
I also considered purchasing like the protopasta magnetic PLA to see if it improves anything, but before this I'm going to try the iron back plate; I also tried to source silicon steel sheet but no luck, maybe in a scrapyard. I will make a youtube video about the full process of machining and assembling the motor, I will keep you updated here!

 

[enrengineering]

Sorry guys for being off some days, I still have homework from the uni and spent some days with the family this easter holidays.
The motor worked with the aluminum back plate and testing it almost all the times started itself. And with the suggestions from you I went further. First, I remade the axle out of a solid stainless bar and changed the way to attach it to the rotor plate, at the end of the shaft I machined a small recess with some tenths over 14 mm to have a bit of a tight fit (see this picture)

With the rotor iron plate roughly cut to a circular shape I drilled a 14mm hole at the center of it and "broached" with a small file a keyway slot, then mounted it to the axle and kept machining the iron plate to final dimensions on the lathe.


The placement of the magnet ring (the same used in version 1) to the iron plate was challenging, my first attempt was with two thick layers of cardboard between the magnet ring and the steel plate and almost all the magnets flew out the ring and went straight to the plate. I pulled out all the magnets and glued them with locktite to the 3d printed ring and I let it sit for a complete day. The second attempt was a success, although I caught my fingers between the iron plate and the magnets I achieved the result I was hoping for:

At this point I was ready to assemble all the parts to complete the motor and have it ready to do some tests. At the first test run almost starts itself and it got up to speed quicker than the aluminum plate. The major downside is that it's not balanced, maybe some magnets weight a bit more than others and are causing the vibration. I tried my best balancing it by adding some nuts and washers to the iron plate, specifically at the threaded sections of the bolts that go through the magnet ring and the iron plate.
Here's the video of machining, assembly and tests of this 3rd version: https://youtu.be/FFnG_2BGiio
Chances are that I'm going to modify the existing axle and fit another iron plate with magnets at the other side, maybe I will do it this summer. Also I thought testing the motor with the VESC or other "serious" controller like the ones that I have on my electric go karts to see where are the limits of this motor. Anyway, thanks for all the suggestions and support so far!
Henry.

 

[Erik952]

@enrengineering

Any updates on this cool motor? I found your youtube channel before I joined ES and I was amazed at your motor! i would love to see any more progress!