On Wed, 2010-03-10 at 09:11 -0800, doug metzler wrote: > for a small stepper motor, like a NEMA 17 I need a small (DC) electrically > driven lock that I can attach to the shaft such that when the power is > turned off the shaft is locked in place. > > Do any of you folks know of such a device? I've been googling around but I > haven't been able to come up with the proper combination of search terms to > get at exactly what I'm looking for. > > Thanks,
My lathe has a Warner electric release brake: http://www.wallacecompany.com/cnc_lathe/HNC/00061-1a.jpg I have noticed a smaller version on my radial arm saw. For your size, you may need to make your own. Basically, there is a metal disk and a matching disk permanent magnet that provides friction by fitting and pulling against the metal disk. One disk is mounted to the motor shaft, the other is mounted to the frame, but some movement of one of the disks along the shaft axis is allowed so that they may release. At this point the brake is always on. A coil is added and energized in a fashion that builds an opposite field to the permanent magnet. With sufficient field, the electromagnet pulls the disks apart, releasing the brake. In the Warner brake the magnet is also the friction material. A search for "nema 17 electric release brake" got this link: http://news.thomasnet.com/news/mechanical-power-transmission/brakes-brake-accessories/electromagnetic-brakes (Short URL) http://alturl.com/4pou There might be other search terms on this page, like "power off brake" Good luck. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
