On Mon, 11 May 2015, Rick Lair wrote: > Date: Mon, 11 May 2015 10:53:40 -0400 > From: Rick Lair <r...@superiorroll.com> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: Emc Users <emc-users@lists.sourceforge.net> > Subject: [Emc-users] Servo Motor Question > > A little off topic, but I figured this would be the best place to ask, > > On one of our turning centers using Linuxcnc, the operator was > complaining of a poor finish on the bores of the parts we were making. > After a lengthy investigation, I saw that while the Z axis was in motion > at low speeds ( the cutting speed range 0-10 IPM ), the motor > shaft/coupling/ball screw is, for lack of a better word, ratcheting > while revolving. I started checking the servo motor, its is a 7.5 KW DC > servo made by Inland, from back in the late 70's. I checked the brushes, > not too badly worn, made sure they moved freely, blew out all the carbon > dust, and checked my resolver, which is mounted inside the servo. > Nothing really sticks outs as being an issue. I watched the position > command, and resolver position feedback, and you can see that the > command is a nice linear line on the scope, but the feedback is choppy, > matching what I see in the motor shaft. It's not severe enough to break > things, or even hear it while in motion, but bad enough that the finish > is not acceptable. > > Any thoughts/ pointers as to what may be causing this? > > -- > > Thanks > > > Rick Lair > Superior Roll & Turning LLC > 399 East Center Street > Petersburg MI, 49270 > PH: 734-279-1831 > FAX: 734-279-1166 > www.superiorroll.com >
Non linear resolver output points to an overloaded input For a 7I49, I would check that the maximum resolver output voltage is less than 1V RMS (you need to rotate the shaft to find the peak on one or measure both sine and cosine and calculate the peak as sqrt(Sine^2+Cosine^2) > > ------------------------------------------------------------------------------ > 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 > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ 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
