RE: [CAD_CAM_EDM_DRO] Re: AC servo motor

It depends on your electronic motor controller.

MACH uses step and direction pulses to run your axis motor.

You "teach" MACH how many thousands of steps your machine needs for "X" to
advance one inch (or metric) and it will store that in its config file.

When you run

;
G01 X4.5 Y0
X5.5
;

MACH will then send the proper number of steps to advance the X axis one
inch and in a positive direction.

Some controllers assign a control voltage to each axis -- 5 volts will equal
five inches, ten=ten and five volts below the reference voltage will equal
G01 X-5.0

These will not work with MACH

These also have the major problem of not scaling well. The longer the size
of "X", the more bits of resolution will be needed to maintain accuracy and
this stuff gets __really__ expensive really fast.

Step and direction sounds like "old school" but it will scale out forever
with zero problems.


AC Servos may be the "best new thing" if you listen to the manufacturers but
DC Servos are just as accurate, the maintenance is minimal and they are
really really cheap.

Dave

> -----Original Message-----
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Horace, T.L.Ho
> Sent: Tuesday, October 03, 2006 9:06 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] Re: AC servo motor
>
>
> Hi Randy,
>
> Thanks. I wonder why don't gecko develop low cost drives for AC
> servos. Is it because drives and AC servos are already a combo sold
> by Yaskawa etc.,so there no such chance for gecko to do so.
>
> And one more thing, is Mach 3 compatible with AC servos ? Sorry if I
> had asked silly questions, I am an idiot in electronics.
>
> Horace.
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, cnc002@... wrote:
> >
> >
> > In a message dated 10/3/2006 12:26:13 P.M. Eastern Daylight Time,
> > rick@... writes:
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Horace, T.L.Ho"
> > <skyfroghorace@> wrote:
> > >
> > > I know this topic must have been discussed before, but I've
> visited
> > one
> > > small CNC maker here even his products use small AC servo
> motor. Why
> > > bother ? We want the problem of brush maintenance be gone for
> good.
> > Any
> > > suggestions ? Thanks in advance
> > >
> > > Horace
> >
> >
> >
> > Horace:
> >
> > AC servo motors don't use brushes as you may already know.
> However, they
> > are usually quite expensive. All of the major CNC machine tool
> builders that I
> > know use AC servos on their products because they are much more
> reliable
> > than the older DC servos and far more accurate and reliable than
> steppers.
> > However, these machines usually cost over $100,000.00 each. I am
> sure there are
> > some lower cost machines that use them as well. I would think,
> if you were
> > doing a hobby machine, you might want to start with less
> expensive hardware.
> > Yaskawa is one of, if not the best, of the AC servo drive
> manufacturers.
> >
> > Hope this helps some,
> >
> >
> > Randy Abernathy
> > 4626 Old Stilesboro Road NW
> > Acworth, GA 30101-4066
> > E-mail: cnc002@...
> >
> > I furnish technical support, repair, and other related services
> for your
> > industrial woodworking machinery. My background as Senior Service
> Engineer for
> > the SCMI Group for nearly fifteen years with factory training,
> combines with
> > my extensive background in electronics, mechanics, pneumatics,
> electrical and
> > CNC machinery to offer you needed support for your machinery.
> Services
> > include but are not limited to the following:
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>
>
>
>
>
>
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