The technical term is chromoly steel...jacobbloy wrote:carbon Steel alloy chrome mix
spinningmagnets wrote:If you can place a steel paperclip onto the side of the motor while the axle is vertical, and the clip stays on rather than falling off...there may be some magnetic flux rotating abouton the outside of the shell. Thickening the steel shell of the outrunner would reduce this. I am not experienced enough to state any of this with authority, but the chiming you heard might be vibrations from eddy-current heating.
Aluminum is not magnetic, but if a magnetic field is moving next to it, it will heat the aluminum and also cause drag on the motor (If I recall correctly). The steel backing of hub motor magnet backing rings "short circuits" the magnetic flux. Too thick results in unnecessary weight, too thin and a variety of other issues arise. These RC motors were designed for very light weight and max torque per applied watt, but the model aircraft housings (that they were intended for) are typically plastic or some other composite, so eddy current heating of surrounding metals is not a frequently seen issue.
If I have mis-stated anything, I apologize in advance, but my hazy recollections might be worth looking into in order to eliminate those issues as possibilities. Perhaps spin up a motor on the bench at max RPMs while using an optical tachometer, then hold various metals nearby to see if the motor slows? (it goes without saying for ES members, but for newer and inexperienced readers, hold the metal in such a way that it might be pulled AWAY from the pliers that hold it...and yes, I have many scars on my hands)
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torqueboards wrote:What's the delivery time?
so + $55 for Orangatang's and ABEC by default included --- both wheels is already assembled if order (2) hub motors?
Also what is max voltage these motors are capable of? What KV are the motors again?
$185 for kegels + 1 hub motor?
What's cost for 2 hub motors? Is 1 hub motor sufficient for uphill?
jacobbloy wrote:I assumed the caps where to blam because even tho there non magnetic they are set closer and are more solid then a normal outrunner
and alloy still even tho it's very low has some iron, but as alloy is steel a conductor
rs4race wrote:Cool stuff. I thought about this a while ago, but didnt want to put in the work to make it happen. I think these will make conversions really easy and sleeper. Really nice!
torqueboards wrote:I clicked on the buy now option as well but I received no option for adding in the full set of kegels to the cost.
amberwolf wrote:jacobbloy wrote:I assumed the caps where to blam because even tho there non magnetic they are set closer and are more solid then a normal outrunner
If you have to have them so close that the stator fields are penetrating them, there are shielding metals you can use as an inside layer. I don't know enough about them to help with that, but Wikipedia does have some info on it, under the magnetism and motor articles, and maybe also the mu-metal / permeability articles.and alloy still even tho it's very low has some iron, but as alloy is steel a conductor
If you mean aluminum alloy, then it isn't steel and shouldn't have iron in it in amounts to make a difference. AFAICR, any metal or alloy is capable of having eddy currents induced into it from a powerful enough magnetic field that is close enough to it, though how each one reacts is different.
"alloy" as a general term only means "a mix of elements" in a material, but what that base material actually is based on is usually the prefix word to it ("aluminum alloy", etc).
If you can shield against the leakage between caps and stator, it may fix the noise, if it's caused by the field, and it would also then make the motor more efficient because it wouldn't be being braked (slightly) by the field leakage into the caps.
Keep in mind the noise in the caps could be caused by flex and/or vibration, too, and might not actually be caused by flux leakage. You wouldn't hear it in ABS caps, becuase the plastic would damp vibration, so even if the cause was still there you wouldn't know. :/
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