@rusins What is this cell comparison tool? Where could I go to learn more about it?
Though these days I just look at Mooch’s e-score tables:
Mooch’s Battery Ratings and E-Scores Tables
Thank you! Looks like an invaluable tool, will have to play around with it.
Onewheel V1 Transverse flux motor TFM 500W pictures.
Can’t exactly make heads or tails of what the motor driving characteristics for this need to be, compared to standard bldc. The coils are where the stator usually is??
I really want to tag @hummieee or anyone who knows the first thing about making motors. Not that traditional motors experience transverses over to this. Btw John do you still offer motor rewinding? Not for this but for a regular ow motor.
@professor_shartsis (joke tag… Unless)
I have enough work winding motors for the moment so just winding what I have for now.
Could still use a Vesc I think.
I thought transverse flux were kinda state-of-the-art n rare but guess not.
What a crazy design, first time I’m seeing something like that
Definitely gonna dig into it for a bit
My first question is why? Seems like you have so much copper weight as non torque producing overhangs (the part of the winding wraps around the teeth to go to the other side) and so much space wasted due to it which still adds material cost and assembly complexity
But there must be a reason to do a design like that
Edit: pretty genius design actually, if you guys want will dig it a bit more and see if I can summarize it, and it’s actually the opposite of what I said above, instead of having windings overhang that are useless to produce torque, essentially all the copper mass in the motor is used to produced torque
Thanks for sharing @Fosterqc
Yes please; very interested
Just to be clear, I’m no motor expert, just starting to dip my toes into it, so I might be wrong in some points
First, saying that a motor is TFM means nothing by itself, I think I’ve found at least 10 different topologies so far, and with quite different characteristics. For example, one use the same stator as regular radial motors (the ones we use), but split in 3 and each stack is a single phase, *(just like the OneWheel above), each stack is a single phase, that seems the worst one, because you have none of the upsides with even more non torque producing copper mass
The biggest advantage it seems so far is that they usually have more torque per unit of mass, but not by volume and also cooling, since all coils are lining flat and not wound in a thin teeth, there is less thermal resistance
Keep in mind the thermal advantage only works if you have forced air cooling going through the center of the stator or water cooling, as in, a small motor like our that there is no space inside for cooling nor that is ever done, this isn’t an advantage (Maybe someone could stuff some heat pipes inside? )
I’m trying to find more comparisons instead of just the motor being evaluated alone
But what I can say so far is that no wonder why current Onewheels doesn’t use that motor, way more expensive and complex to produce with barely if any advantage for that use case
This remembers a bit of speaker design (which I know way more than motors), in the end of the day, for a given box volume or material weight, you can’t break physics and expect better performance and usually you arrive at remarkably close results with vastly different designs
63661.pdf (590.6 KB)
1-s2.0-S2352484722014767-main.pdf (1.9 MB)
The Journal of Engineering - 2019 - Martinez‐Oca a - Transverse flux machines as an alternative to radial flux machines in.pdf (1.9 MB)
energies-14-07690.pdf (4.0 MB)
Yeah of the many papers I looked at none really boiled down the info to something I found helpful.
Here is one cool video of a diy 3d printed TFM
includes this great bit on the problems using halls for position sensing.
I was gonna share that but found the design quite different from the OneWheel one
@Deodand sent me this, the manufacturer of that motor
They shed some good light on the advantages, it simply allows you to lower your Kv without changing phase resistance, just by adding more poles and slot, huge gains there
Yeah I found in the Onewheel Kickstarter updates they describe ETM’s engineers as “Motor Wizards”
I was considering trying to get technical advice from ETM. I would have a hard time doing the electrical testing and being able to convey the information well enough to find solutions.
Best case I think would be if the conversation is between Benjamin Vedder and ETM.
I think the biggest obstacle for us or any small company doing it is development cost, specially the softwares you need
They way the paper do is fine, but not optimal when you developing a product from it
There must be a good reason for OneWheel to have dropped it, and they had money
I failed to mention the major motor torque cutout issues so far. I was hoping it was something basic I missed but no.
So while the board rides its not able to stay engaged due to the TFM properties not lining up with the VESC firmware’s expectations.
here are the videos showing it that we finally have for you all to look at.
That last video playlist is for showing problems/development on the V1 motors.
This playlist is gonna have more like riding videos, wiring guides for the V1 and all that.
Its been following the Andrew Tate course. Its a top G now.
Given it’s TRANSverse flux I don’t think that persona matches up.