Everything is shielded.
By chance, we installed a 10 microfarad capacitor on the 5 volt power wire that powers up our encoder and "Bigo!" all is great in the universe. We also found out that the capacitor had to be installed within a few inches of the encoder. If we installed it at the Gecko, it wouldn't help. All 3 axis repeat now on a travle indicator within .0005in. --- In [EMAIL PROTECTED], "vavaroutsos" <[EMAIL PROTECTED]> wrote: > > Sounds to me like you are getting noise on your Z encoder. Are you > running single ended encoders, or differential with converters? Are > the encoder cables shielded? Did you use shielded VFD cable from the > VFD to the spindle motor? How are your ground connections oriented? > > ~petev > > --- In [EMAIL PROTECTED], "yethdear0" <[EMAIL PROTECTED]> > wrote: > > > > Hiya, > > > > We have an old Hurco knee mill that we have stripped and retro-ed > > with a pc, CNCPro, Geckos and a Baldor VFD for the spindle motor. > We > > just got it all up and running but have a problem with the Z axis > > servo or controller. Using a travel indicator on the Z axis, the > > movement is smooth and exact. We have the machine running a program > > that move Z -.100" pauses for 1 second and then moves Z +.100" and > > then runs in a loop. When we turn on the VFD and the spindle, the Z > > axis seems noisy and the travel on the indicator will start to > > drift .001" to .005" each time the program cycles. The drift is > > random, sometimes positive and sometimes negative but positive the > > majority of the time. When we slowed the motion to 1 ipm, you can > > see the motion twitch at random during the movement. This only > > happens when the spindle is running and only the on the Z axis. We > > swapped out the servo motors with the Y axis and the problem stayed > > with the Z axis controller. On the machine, the Z axis servo is > > mounted on the front of the spindle head of the machine, the motor > > (5hp, 230V, 3ph,) is on the back of the head. The VFD (a new > Baldor) > > is mounted on the side of the head about 6in from the Z servo. We > > also dismounted the Z servo and located it away from the motor and > > VFD to test for magnetic flux or noise and it still twitches. We > > have also played with the gain and damping adjustment but nothing > > there would correct the problem. The twitching is only in Z, all 3 > > Geckos are getting their power from the same DC power source which > > baffles us why the twitching is only on the Z axis. We are also > > using new US Digital encoders. When we swapped servos though, we > > also swapped encoders and the twitching stays on the Z axis. We > also > > rerouted cables as far from our VFD and motor as possible but still > > have the problem. > > > > Any suggestions or input will be greatly appreciated, thanks. Addresses: FAQ: http://www.ktmarketing.com/faq.html FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/ Post Messages: [EMAIL PROTECTED] Subscribe: [EMAIL PROTECTED] Unsubscribe: [EMAIL PROTECTED] List owner: [EMAIL PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED] Moderator: [EMAIL PROTECTED] [EMAIL PROTECTED] [EMAIL PROTECTED] [Moderators] URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO OFF Topic POSTS: General Machining If you wish to post on unlimited OT subjects goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble. http://www.metalworking.com/news_servers.html http://groups.yahoo.com/group/jobshophomeshop I consider this to be a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list. NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ bill List Mom List Owner Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
