Re: Plasma Voltage Servo

Ballendo, My hypertherm has a terminal board to tap into for just
this purpose. Thanks,
Dale



-- In CAD_CAM_EDM_DRO@y..., "ballendo" <ballendo@y...> wrote:

> Tom, Aspaguy,
>
> I'm not familiar with plasma cutting systems. Where is this
> voltage "taken from"? Is there a "tap" on the unit somewhere?
>
> Thank you in advance.
>
> Ballendo
>
> --- In CAD_CAM_EDM_DRO@y..., "ths992001" <thscarince@h...> wrote:
> > WRT plasma arc voltage vs torch to work distance:
> >
> > Once I read an Amercan Welding Society paper on this subject.
> > According to this article, the arc voltage wavform is something

of

> a
> > sawtooth. At the beginning of the cycle the arch starts at the

top

> > of the material at a certain voltage. As it rapidly burns its

way

> > down the face of the cut, the voltage ramps up to some peak at

the

> > bottom surface of the material. At this point, the arc jumps

back

> to
> > the top surface and the cycle begins again.
> >
> > This means that the average arc voltage may not be an ideal
> > indication of the torch height in all conditions (material,
> > thickness, feed rate, amps, target height...). The author

proposed

> > using the "peak low" (the base of the sawtooth) voltage as this
> best
> > represents the actual height under varying conditions.
> >
> > Got an extra op amp for an averaging peak (or valley, in this

case)

> > detector Mariss? Seriously, his design will probably do the

trick

> > just fine in the real world.
> >
> > Tom Scarince