On Sat, Jan 22, 2011 at 08:41:19AM -0800, Kirk Wallace wrote: > I have been thinking about this too. There is a fair amount of activity > with DIY out-runner motors in the model airplane community. > Occasionally, they can get enough orders together to have a batch of > custom silicon steel laminations made. The bell, magnets, bearings, hub > and stator windings are easy enough for an individual to make.
A while ago, Model Engineering Workshop had an article on making outrunner BLDC motors. These were based on the rotor from something like a discarded drill. The windings were hacksawed at the ends, and peeled out. The commutator is also not needed, obviously. New windings on what is now the stator, and monster magnets inside the outrunner, plus new bearings, and you're off, at 10 to 20,000 RPM. The author just used model aircraft BLDC controllers, though. There is no chance that I'd finish the project if I added motor building to the end of the row to hoe. (Too much else already started, and not yet finished. ;-) > There is at least one person on this list that has an out-runner on > their mill spindle. Typically these motors don't have rotor sensors, > so adding Hall sensors will most likely be needed if one wants to > start the motor with a load. These can presumably be optical instead, if that's what's in the junkbox, and this 120°/step encoder is enclosed, to keep it clean. > I would really like to try to make an out-runner that caters to an axis > application. In MEW, it was used as a high speed spindle. But being able to use the lathe spindle as a rotary axis would be very nice, with a milling head on the cross-slide. But that would take a hefty motor. (My mill-drill isn't worth converting, and too useful as a manual.) Oh, now I remember. Some years ago I toyed with the idea of using a truck alternator as a BLDC motor. They seem to be common now, and this one is chewing about 130W, just flailing air: http://www.avagotech.com/docs/AV02-0188EN If mesa or pico have a controller which will drive e.g. a 24v 50A truck alternator as a BLDC, I think I'd take the easy way out, and just add some "hall" sensors. Erik ------------------------------------------------------------------------------ Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
