Re: high-performance EDM power supply

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jerry Kimberlin
<kimberln@c...> wrote:

> Graham Stabler wrote:
>
> >It seems to me that a chunky DC supply a, chunky mosfet and a

decent

> >pulse generator to drive the gate would be a good start for
> >experimentation.
> >
> The DC power supply doesn't have to be too sophisticated. 30 years

ago

> when I was copying every research article I could get on EDM, I

sort of

> decided that the power output from a 48 Vac @ 20 Amp transformer

would

> do the job. Note that the voltage would be around 65 Vdc. A

couple

> capacitors and a choke added on might be that chunky DC supply you

mention.

>
> What I found out during 6 months of collecting and reading articles

is

> that the spark (desirable) and arc (undesirable) sensing circuitry

can

> be quite sophisticated. Well, that was 30 years ago and there are
> integrated circuits and solid state devices now that are far

better.

> Still, the sensing circuits are very important and these have to be
> connected in some sort of feedback mode to the stepper drivers.

Since this is a major part of the circuit, it would seem that some
attention is needed.

a simple RC circuit monitors the sparking cap voltage, too high and
it backs off. probably, one could do the same with a pulser, and for
the home use, who cares if it misses once in awhile.

Dave