Re: [CAD_CAM_EDM_DRO] Re: micro wire-edm project (and software solution)

What voltage and currents do most use for EDM ?
Constant current is not hard to produce.
Do you maintain given distance away from the material to be cut ?

I guess I need to get a book on the subject.
Jim

----- Original Message -----
From: "Graham Stabler" <eexgs@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Friday, October 28, 2005 4:05 AM
Subject: [CAD_CAM_EDM_DRO] Re: micro wire-edm project (and software
solution)


>
>> A current sense resistor has to be able to handle the total current.
>> diodes are cheap in comparison. They have a high voltage drop which
>> is not always a good thing, but can make monitoring the current easy.
>> But, did I mention they are cheap ?
>>
>
> I am still a little confused as the voltage drop over a diode will be
> its forward voltage and that is not normally very large. The voltage
> drop will not be proportional to current and as you would still need
> to limit the current you could use the current limiting resister.
>
>> Many of the low end RC EDM machines use them as the sense voltage
> source.
>
> So they are not using them as a voltage references?
>
> I will probably measure gap voltage anyway to be quite honest and if I
> were to use a shunt it could be a tiny value, at the low intended
> currents it would not need to be all that big or expensive.
>
> Graham
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