Hello Nicklas, On 08/17/16 00:40, Nicklas Karlsson wrote: > I have tried to use voltage to control EDM gap distance but are not sure this > is the correct method. I found a paper there someone suggested gap resistance > is a non linear function of gap distance. the gap resistance is used indirectly.. first the dielectric constant of the fluid is 'like' a resistor ( untill a plasma spark is let thru it) so, the voltage across this resistor can be a measure of the gap distance
> > They also stated ignition delay time depend on gap distance. if the ignition delay beocmes low, it indicates the tool is too close or the gap fluid resistance has changed ( read 'dirty', and therefore less resistance ) so it is not an analog a method as teh gap resistance, more like a boolean saying "get back & wait longer between sparks!" > I am not totally sure if there is a correlation between gap distance and have > not seen it in my measurements. Regards Nicklas Karlsson -------------------------- some edm models use it i'll try to dig some up pretty technical but you seem to handle these data fine ;-) here: *http://tinyurl.com/h4p32ny* checkout Rig in section 3.2 "Ignition Phase" """ The gap voltage is refers to the voltage through resistor Rig which is become a voltage divider between resistors Rig and Rshunt. """ Rig is the resistance to the inition ( the gap resistance ) Rshint is the current limiting resistor in a classic transistiorized generator. This article makes no determination of distance according to the result, getting a number is not the way an electronic (non-math) servo works. an electrical servo balances the voltage you want to the voltage you got. distance is just a by-product, outside of the servo. do you want a number? if so, why? also here: http://www.wseas.us/e-library/transactions/systems/2009/29-363.pdf and at http://documents.tips search for Modeling and adaptive control of EDM systems (good paper by Dr Rajakur at Uni Nebraska , he's prolific in these papers) you'll have to wade thru 'gotchas' and other cruft but no signup, no fee, no tracking hth tomp tjtr33 ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
