Re: more thoughts on torch height

Mariss, at Don Chandlers suggestion, I went to my Hypertherm manual
and the reccomended arc voltages range from 107 to 129 volts. Using
a 50:1 voltage divider this would give a useable voltage of 2.18-2.58
volts. This is at 1/16 clearance from the work. I wonder how much the
voltage varies in 1/16 before it would allow the tip to crash into
the work. It must vary enough, as their are several companies making
complete systems based on this technology. I wonder if the voltage
divider could be designed into the circuit too.
Thanks again,
Dale

--- In CAD_CAM_EDM_DRO@y..., "aspaguy" <spaguy@l...> wrote:
> Mariss, Thanks for jumping on this,I think it could be developed
into
> something helpful for most people in the plasma field. I think the
> information you need for the voltage is available on the pdf at the
> Rutex sight www.rutex.f2s.com/flame1.html Click on the plasma
> THC to go to the pdf. I will copy the paragraph that I think
> pinpoints it and e-mail it to you off list. The last time I copied
> info from a website to post, the post vanished, probably a
copyright
> thing. I posted the sight address this time so anyone wanting to
> follow this thread can do so.
> Now for newby Questions, What is hysterisis? Also, this may
sound
> stupid, but when you say "servo to" you do mean the voltage that
will
> control the unit and not something about a servo moter, right?
> because I'm hoping to run this unit with a stepper moter. I'm
pretty
> sure I'm on the right track here, but dumb questions are easier to
> deal with than dumb mistakes.
> Thanks
>
Dale
>

> -
--
> In CAD_CAM_EDM_DRO@y..., "mariss92705" <mariss92705@y...> wrote:
> > Dale,
> >
> > I've got the circuit worked out; voltage in, step and direction
out
> > with hysterisis . It takes a quad comparator (LM339), a dozen
> > resistors and two caps; about $1.50 in parts at Radio Shack
prices.
> > It would be very helpful to know what voltage you want to servo
to.
> >
> > When I have that, I can scale the input resistors and post the
> > diagram.
> >
> > Mariss
> >
> > --- In CAD_CAM_EDM_DRO@y..., "aspaguy" <spaguy@l...> wrote:
> > > The following is an exerpt from a shopbot page about upgrades.
> > > perhaps it will be of help. They seem to be using the same z
axis
> > for
> > > torch height control. I have e-mailed them for more info, but
> don't
> > > know what to expect as a non shopbot owner.
> > > Thanks,
> > >
> > Dale