On Thu, 2007-12-06 at 23:01 -0500, xtra209 wrote: > I checked out some treadmill motors rescued from defunct treadmills and > discovered they are really not reversible. Mine will run in both > directions but one direction the armature arcs more than the other > direction. A closer investigation of the motor showed that the brushes > contact the commutator at an angle. Sooo... My treadmill motor isn't > designed to run both directions. Maybe you are moving the brushes > backwards causing problems? I think the motor I have is only suitable > for the direction it is designed to run. > > Maybe this will help... > > Clint
I was lucky. My motors have the brushes located axially. I have not noticed much arcing at all. I do have some other issues with the motors, such as, the rotor has straight windings where some motors have a twist to the laminations which I think is supposed to provide a more constant torque. I powered them with my lab supply and I was able to run them very slowly without any galloping or stopping at a particular location. The rear bearing is tiny compared to the front and is mounted in plastic, which shouldn't be a problem if I keep my belt tension at a reasonable level. The front bearing has a spring which biases the rotor towards the rear bearing. If I push on the rear shaft, I can move the rotor against the spring about .030". I haven't decided if this is going to be a problem. It may be, if I fit an encoder to the rear shaft, but there should be no side loads. This is the motor here: http://surpluscenter.com/item.asp?UID=2007120702032835&item=10-1783-A&catname=electric At $20 each, I wanted to see if any money could be saved compared to a real servo motor with the same ratings. It may be a wash since I had to machine a new front bearing mount to provide for mounting, but it depends on the value of my time. With 3:1 (actually 40:13) ratio pulleys, it scoots pretty well. At certain loads, though, it makes a faint moose mating call. I find it hard to concentrate on my work when it does that. -- Kirk Wallace (California, USA http://www.wallacecompany.com/machine_shop/ Hardinge HNC lathe, Bridgeport mill conversion, doing XY now, Zubal lathe conversion pending) ------------------------------------------------------------------------- SF.Net email is sponsored by: Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
