Axial flux motor not rotating but vibrating.

[imraj]

Hi,

We are working on an axial flux electric DC motor as using in "Build your own electric motor by Axel Borg" as a guide but with some variations like magnet size etc.

We assembled the rotor and stator as stated using 10x3 neodymium magnets, 6 coils combining 4 sets of 10*3 neodymium for each coil, 100amps 5v esc, 12v 65ah battery but motor is vibrating in place and we couldn't get it to rotate.

We can't seem to figure out what we are doing wrong and any help to get it to work fine is really appreciated.

Picture of the assembly - https://imgur.com/kqYFf03

Short clip of the vibration - https://imgur.com/DF4Pj5x

Coils - https://imgur.com/Qd07v1C

https://imgur.com/a/2k81c4x

 

[amberwolf]

Are all the coils wound in the correct direction?

Are they all wired in the correct sequence?

Are all the magnets in the correct polarity for their position in sequence?

Any one being wrong could cause it to be unable to spin under controller power.

 

[imraj]

Yes the magnets are in arranged in alternating polarity in the sequence.
Can you please expand on what you mean by coil direction and sequence?

 

[amberwolf]

Depending on the winding pattern, the coil has to be wound in a certain direction to make the current flow the way you need it to cause the motor to spin.

If you have say, a pair of coils on opposite sides of the center where one is wound the right way and the other is not, the motor can't spin because they're not both doing the same thing--say one is pulling toward the next pole, and the other is pushing against the same pole--it's equal strength so it can't move. If you wind a coil one direction, it gets one magnetic field orientation. If it's wound the other way, it's the opposite field.

Sequence means which coils around the motor are wired to the U phase, which to the V, and which to the W. (some designers use A, B, and C instead of U, V, and W, same thing). If the sequence is wrong, like if one set of coils goes UVW and the next UVW and the next UWV, it doesn't work because two coils are swapped in one of the segments, so when energizing the Us it'll work but when you energize the Ws two of htem are working but the third is against the wrong magnets and won't move correctly.


For this specific motor design I don't know what your winding pattern has to be. You'd have to refer to the design page(s) for it for how it must be wired.


Another problem can be is if you have an even number of magnets and coils; it can cause the motor to line up with a set and then no longer be able to move--all magnets and all coils are aligned, so there's no push or pull to make the motor spin--it just holds it in place (maybe with a little wiggle or vibration if the alignment isn't perfect).

If you have an odd number of coils and an even number of magnets, it will never be able to align like that and get "stuck" (assuming it's wound correctly and the magnets are correct polarity). The more coils and the more magnets the smoother the rotation will be, as well, because there is a smaller distance between each pairing to move.


If it's useful, there are some how-things-work threads at the top of this subforum, including the sticky index thread that links a bunch of information, and also a number of DIY motor threads here in this subforum, that go thru various things like the above, and other types of troubleshooting problems (even including materials and shapes). Of the DIY's, I'd start with APL's, and then go from there. https://endless-sphere.com/forums/viewtopic.php?f=30&t=97860

 

[imraj]

Thank you very much for your detailed response. We are checking the coils again and will also checkout the other threads mentioned.