Re: Chinese drives from Keeling Do you have a Link?

John,
Do you have a link for these Chinese drives from Keeling?
Larry


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "John Stevenson" <john@...>
wrote:

>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@> wrote:
> >
> > rocketscientistnate wrote:
> > I'm running Gecko 201's with the
> > > original steppers, and I thinking that if I trade those out

for some

> > > new steppers it will probably fix it. I'm looking at some

from

> > > Tormach, I understand their mills are pretty good so maybe

their

> motors
> > > are too. First I want to make sure the 1200 oz-in is the

right size,

> > > maybe the 640 oz-in for the z and a axes.
> >
> > Why do you believe changing the motors will stop it from losing
> > steps? Does it do this only on occasion or frequently? Do you
> > hear obvious stalls of the motors, or is the positioning just
> > creeping over time?
> >
> > What software are you running? What type of interface do you
> > have between the parallel port and the Gecko drives?
> >
> > There are well-known problems between certain programs, certain
> > settings and certain vintages of Gecko drives that misinterpret
> > step command right around direction changes. The older Gecko
> > 210 drives with the pulse multipliers are the most finicky, but
> > you can get almost any Gecko 201 to do the same (lose a step
> > often during axis reversal) if the timing between the step
> > pulses and the direction signal is not right. I wouldn't lay
> > out serious money on new motors until I was sure this problem
> > was ruled out.
> >
> > Jon
> >
>
> Jon,
> The problem with the old BOSS machines is they big 42 motors are

not

> suited to the Gecko drives.
> They are just too big and require too much power, typically 9 amps

to

> be reliable.
>
> Most were only 850 to 900 oz/in and with time probably a lot less

than

> that. The modern 34's can use less power, have faster acceleration

and

> be far more reliable.
>
> As you say early to mid release Gecko's are the worse. I can get

these

> to run reliably with the Chinese drives from Keeling but not

Gecko's.

>
> I have had a Divisionmaster indexer driving a big Hoffman dividing
> head via a 201 Gecko and it has been loosing steps for a while.
> Last week I needed some accurate splines so tested the head by

setting

> to 10 divisions and doing 5 rotations. At the end of the 5

rotations I

> was 1/2 a hole [ 5mm ] off the mark.
>
> Just swapping the driver to the Chinese 7.9 amp one and retesting

gave

> me no visable error at 10 rotations.
>
> I also have a BOSS going thru refit and that is having 1100 oz/in
> motors and the Chinese drives fitted.
>
> John S.
>