Re: EDM Controller Qustion

James, I don't know what type of EDM you are building, so maybe the
info I can supply won't apply. Mine is sort of like Robert Langlois
design. It uses a stepping motor driving a fine leadscrew to move the
electrode. A comparator senses the gap volts and moves the electrode
like in your description below. I find it important to set the
reference voltage on the comparator carefully to keep the electrode
floating in the gap and not short to the work, for ideal operation.
When you get it right it just hums along! I have been doing much more
than burning out broken taps etc. Richard

--- In CAD_CAM_EDM_DRO@y..., "James Stevens" <stevens@c...> wrote:
> In searching the archives and other sources, I understand the basic
controls of the EDM as follows:
>
> 1 - Measure voltage when electrode discharges
> 2 - If V < desired gap voltage, move electrode up (too close)
> 3 - If V = desired gap voltage, don't move electrode
> 4 - If V > desired gap voltage, move electrode down (too far away)
> 5 - Goto 1
>
> This is just a simplification but is sufficient for my question.
>
> When you build your own power supply, you have a capacitor at the
output. This is what you measure (V). When you purchase your power
supply, what do you measure? Can I assume that there is also a
capacitor at the output of the power supply that I can measure the
same way?
>
> Also, for any usefull work to be accomplished, there must be power
(P=V*I). If there is high voltage and no current then there is no
power. If I'm using a shunt resistor to measure the voltage, and a
voltage is measured, then there will be current (I=V / R). Likewise,
if I try to measure current with the shunt resistor, and a current is
measured, then there will be a voltage (V=I * R). Do I need to worry
about this or does measuring one validate the other?
>
> I would appreciate any help anyone has to offer on EDM'ing.
>
> Regards,
>
> James
>
>
> [Non-text portions of this message have been removed]