On 10/8/2015 8:31 AM, TJoseph Powderly wrote: > On 10/08/2015 03:18 AM, Marshland Engineering wrote: >> Apparently DC Brushless cog but not AC ? >> Anyway I'm about to order a 6N.m 1.8KW AC motor and drive for $340. It's >> worth a try. >> > no, I found Ac drives cogging, and the _brushed_ dc drives did not > >> Brushes ?? My South Western Industries mill has run 20+ hours a week for + 10 >> years and I have never changed a brush. Maybe I should check sometime. >> > if you got ;em, clean 'em > >> Possibly if the motors are under powered, they need changing more often. I >> changed my first set of cordless drill brushes a month ago. >> > my experience is with very large dc brushed motors, you couldnt carry 2 > of 'em > Could it be that the brushed DC motors you were using were made for ultra slow speed operation?
I used a lot of AC Brushless servos and have never seen cogging issues but then the motors are always running RPM's not fractions of RPM's. :-) Poorly tuned AC Brushless drive/motors will cog. The Teco servos have self tuning routines in the ones I have used. The tuning has to be enabled and the motor exercised and then I turn the self tuning off once the motor is responding properly. I found that if I did not do that, that the Teco self tuning would try to compensate for improper tuning in LinuxCNC! Dave --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
