Using software.
Why don’t people use drone motors with their many poles and low cogging for eskate? Get a better coast.
1 Like
Can you even feel cogging at anything slower than a child’s walking pace? Maybe on direct drive you could, but that has less resistance anyway.
Edit: Cool article
2 Likes
3mph+ it’s a non-issue.
Who rides at 2mph anyways? slower than walking and sensors help you if you care about startup. Of course not everyone wants sensors.
1 Like
There’s confusion on the term. Cogging torque is there at all speeds and a resistance when coasting. It also causes torque ripple when powered.
A belt greatly reduces coasting but the common 12n14p motors everyone is using have bad cogging torque. A drone motor with many more poles seems better for eskate because of this alone. Rc plane people don’t glide much so they don’t care but for us it’s a bit of a mismatch
At lower speeds the torque is relatively greater and commutation timing can be detrimentally effected to the point the motor isn’t even moving, giving “cogging” but the resistance is there at all speeds increasing linearly w speed I think. And not iron losses
2 Likes
If I recall there was some discussion on spiral wound motors (or something with curved magnets) that would aid with reduction of cogging force, or make it smoother?
1 Like
Skewering teeth or magnets. Yea but lower power. The easy way with no loss in power is increasing the poles.
Drone motors mostly run in bldc correct? I doubt sensorless FOC, probably some high end drones use sensored motors.
1 Like
Bldc or sine or foc cogging will be the same based on motor design.
1 Like
Wouldn’t you need a super high ermp limit?
1 Like
This is R&D for that I assume 
1 Like
For what reason?
R and d leads to programming or better yet n ideal teeth and pole amount.
@Kellag where would I be without u to remind.
4 Likes
To get a rotation from the motor it needs to switch way more, but I guess that cancels out the torque and you’ve basically got low kv motors?
W many poles there’s higher erpm per rpm but iron losses are peanuts at speeds we do and increasing them not a big deal and would come w the easy coast.
1 Like
Sf is pretty nice. Rather make the dopest flyest hubs.
3 Likes
That article is for servo control…
The idea is to determine the voltage needed to at every single encoder pulse to produce a uniform torque.
2 Likes
or…for hobby brushless motors. ive seen similar also used for electric bikes.
I don’t remember from my head exactly why, but skewing the magnets doesn’t have the same effect as skewing the the teeth’s
Can look it up latter, and if I remember depending how you did it the power loss was insignificant
1 Like