Re: LARGE Gantry table: Geckos on large servos.

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Kim Lux <lux@d...> wrote:
> I don't know if a Gecko will run a really large servo motor.
>
> We've got a 3HP servo motor, depowered by running at 80V, on a
large
> table of a special machine. We recently tested it with a Gecko
320 and
> blew it up. It would operate fine at lower speeds, but the drive
ran
> warm. At higher speeds, the drive failed. It seemed to have
problems
> getting the damping/gain correct for such a large motor.
>
> We sent the drive back to Gecko. They looked at it but have not
> commented on what exactly caused it to fail.
>
> I suspect that the motor would draw more than the rated max drive
> current (ie 20Amps) during acceleration.
>
> Kim
>
>
>
>
> On Tue, 2004-03-09 at 17:03, Leslie M. Watts wrote:
> > Heh. Confused Chris? My friend Bob Campbell said a Gecko would
> > handle it. I said it would need something bigger.
> >
> > To put things in perspective my 1000 lb gantry IS run by a Copley
> > 412 which is about the same as a Gecko in power. So Bob is
absolutely
> > correct for the weight you asked about.
> >
> > I just think that a 20 ft gantry will be much more massive than
my
> > system. Things tend to go up in mass as the cube of length for
equivalent
> > stiffness. Sometimes even more. A finite element structure
analysis
> > can define this in the design stage.
> >
> > Les
> >
> > Leslie M.Watts
> > L M Watts Furniture
> > Tiger Georgia USA
> > (706) 212-0242
> > http://www.lmwatts.com
> > Engineering page:
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> > CNC surplus for sale:
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> > CNC carved signs:
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> >
> >
> >
> >
> > -----Original Message-----
> > From: Robert Campbell [mailto:bob@c...]
> > Sent: Tuesday, March 09, 2004 6:09 PM
> > To: CAD_CAM_EDM_DRO@yahoogroups.com
> > Subject: Re: [CAD_CAM_EDM_DRO] LARGE Gantry table
> >
> >
> > Chris,
> >
> > You will defiantly need a servo system. I would think that a
Gecko drive
> > would do it.
> >
> > You may want to post on the Gecko drive list.
> >
> >
> > Bob Campbell
> > Bob@c...
> > www.campbelldesigns.com
> > Breakout board
> > THC board sets
> > CNC router plans
> > Stepper Motors
> > ----- Original Message -----
> > From: "cutthroatplasmaco" <cutthroatplasmaco@y...>
> > To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> > Sent: Tuesday, March 09, 2004 3:52 PM
> > Subject: [CAD_CAM_EDM_DRO] LARGE Gantry table
> >
> >
> > > Can someone point me in the direction of suppliers for
motors/drives
> > > for LARGE gantry machines... I'm talking 20'x40' cutting area.
Off
> > > the top of my head, I'm guessing the gantry might way a half
ton or
> > > more. I'm very familiar with smaller steppers/servos, I just
don't
> > > quite understand where/what route you take when talking about
large
> > > machines that need significant torque to make a 1000lb gantry
change
> > > directions on a dime. It seems you need an ac servo that would
run
> > > off of signicantly more power than a gecko or similar can
provide.
> > > Any help/links would be appreciated.
> > > Thanks,
> > > Chris
> > >
> > >
> > >
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> > http://groups.yahoo.com/group/jobshophomeshop I consider this
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> > 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.
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> > NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY
POSTING THEM.
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[Moderators]
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> >
> > 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
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> > 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........
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> --
> Kim Lux <lux@d...>