Discussion about cogging


(I tried to move your posts here, but our “502 error” system issues would not allow it.)


to summarize hummie says he thinks cogging causes unpowered losses.

i say whether there’s cogging or not, i suspect the losses will be the same and result from eddy currents. this is because the cogging stores and releases potential energy, like a spring.

blupenguin says if the cogging causes additional losses, by spinning the test motors unpowered at constant speed, the motor that’s less efficient will end up hotter.

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Not what I said. There’s theory that it’s like a gravity field as well as I wrote. I’m not saying anything other than there is a loss of coasting to cogging and it’s not eddies.

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For starters no one claims cogging to be eddies. That’s not the scientific view.

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when you lose kinetic energy with cogging, you store potential energy and then you get kinetic energy again when you move the motor past the potential energy peak. momentum and energy are conserved.

Except not net zero so not conserved.

when you push 2 north poles of 2 magnets together, you store energy (as in a spring) and you get the energy you used to compress them back as you release the magents, because they move apart with the same energy that was applied if they are constrained to one axis of freedom

For my money there is only one opinion here as only one if you have built a board and has practical experience.

When speaking of theory you should make a statement and then let it go until you can prove it. You seem to have no interest in proving any of these abstract notions. Until that happens how about not spamming others threads.


i’ve hand wound a hummie motor…

Not that I ever saw or ran

Some things are evident: cogging happens and momentum is lost.
eddies show differently and so does traditional hysteresis.
Don’t know how this discussion started but I’m open to ideas just saying no traditional hysteresis acts in such a way. And for sure not eddies. U can just look at slotless motors to see they don’t cog but have same conductive material passing magnets. If u make the slot minuscule the cogging follows


momentum isn’t lost, it’s conserved. i’d like to hear where you think it’s going if not eddy currents.

As I wrote there’s different theories. Some have the mag field like a gravity field. Maybe lost to some slow moving version of hysteresis

and with an orbiting body in a gravity field kinetic energy is converted repeatedly to potential energy and back to kinetic energy… it’s never lost. highest kinetic energy and lowest potential energy occurs at periapsis. the potential energy is highest (and kinetic energy lowest) at apoapsis. at all times kinetic + potential energy remains constant.

i wound one the same day you and luke were putting in magnets on my back porch, you just don’t remember apparently.

I remember u winding but never ran. Never attempted to run.

in any case if cogging causes a loss of momentum with sufficient board inertia to overcome the potential energy peaks, or a net loss of board kinetic energy… where exactly are you saying that momentum and energy goes, if not eddy currents? momentum and energy are never destroyed.

It’s almost like you’re suggesting that in order to be helpful in discussion on a topic, one might want to be respectful of everyone else’s time and gain experience in said topic before trying to ‘help’.

Furthermore, one could stretch that having actual experience often speaks towards understanding the theory, as opposed to career armchair speculatists who preach pure theory without practice.

Gee golly, imagine that.


you’re forgetting i own hummie v4’s and a v1, have ridden them, have wound one, have been present during their windings, have been involved in design discussions, ride electric skateboards, and have assembled electric vehicles

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“don’t flatter yourself, I have no idea what you’re fucking eluding to”

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yea i built a couple hub motor ev’s back in 2006… one of them was gifted to hummie and he sold to luke who still owns it