On 05/15/2015 08:29 AM, Jon Elson wrote: > On 05/15/2015 08:44 AM, kqt4a...@gmail.com wrote: >> As I understand an AC brushed motor(drill, router, saw) can be controlled >> by varying the voltage with something like a light dimmer but with great >> loss of torque >> Can a motor like this be controlled with pwm >> >> > Yes, but you still lose torque. It takes time for the > current in the field to build up, due to inductance. > If you were to rewire the motor so a separate DC field > current could be supplied, and the armature was supplied the > PWM DC, it would get full torque, and slow down much less > under load.
I have a soft spot for these SCR speed controllers: http://www.kbelectronics.com/manuals/kbic_manual.pdf They can run DC motors or AC universal motors, plus have a separate field source if needed (see page 8). They use back EMF for speed feedback and regulate speed very well with high torque. Isolated PWM can be used from LinuxCNC to control speed. Used units from eBay can be pretty cheap if one waits for a good deal: http://www.ebay.com/sch/i.html?_from=R40&_nkw=kbic -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
