On Monday 28 September 2009, Sven Wesley wrote: >I replaced the servo/encoder yesterday night and the result is the same. So >what do i have left to try? I'll test if the tuning software creates the >same behaviour (different computer, different OS...) and I'll try Toms >suggestion to add a filtering capacitor on the step signal. >I also found an old spec sheet for the servo's. I'm surprised it says that >the servo's are really good for plotters. To me plotter motors are small > and these are compact but not _that_ small. I have the J03M-series motors, > rated at 65 V and 10 A according to the label on the servo. The > specification says 54.2 oz-in rated torque and 266 peak (0.4 resp 1.9 Nm). > Could it be that they are too small? I think that's not the case and even > if I run my test with low speeds around 200 mm/min the offset appears. >http://www.yaskawa.com/site/DMServo.nsf/(DocID)/TKUR-5ELJ3U/$File/TSE-C249- >13B.pdf > >I'm running out of options soon... :( > My instant reaction is that they are very inefficient. I would call that size about a nema 17, which would be about right for a plotter, but without lots of geardown, would be a bit small for a milling machine even as small as my HF micromill. If your driver is actually hitting them with 65 volts and 10 amps per winding, that is 1300 watts, and a motor of that size cannot survive that sort of power for very long. Since they have, I doubt the driver is actually hitting it that hard.
Normally for smaller stuff, we use a nema 23 motor, and the ones xylotek sells are either triple or quadruple stack lengths. The triple stack can do 262 oz/in, the quadruple stack length does 425 at their rated currents. The xylotex driver is limited to 2.5 amps, so they are getting about 3/4 of their rated. My rebuilt z can put 155 lbs of downforce when that 425 starts cogging & slipping. and can under ideal conditions do something on the north side of 30 ipm non cutting. This is with a 28 volt supply. A 65 volt supply would about double the speeds, but the xylotex has an absolute max of 30 volts. The triple stacks on the x/y can break a 1/4" solid carbide mill if the spindle motor blows a fuse, and have several times. I think I'd investigate a larger, 23 sized motor, at least for the z. [...] -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) The NRA is offering FREE Associate memberships to anyone who wants them. <https://www.nrahq.org/nrabonus/accept-membership.asp> If you keep your mind sufficiently open, people will throw a lot of rubbish into it. -- William Orton ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
