From: hwabnig@.-   
      
   On Mon, 29 Jan 2018 10:21:01 -0800, etpm@whidbey.com wrote:   
      
   >Reecently I helped a neighbor connect a Chinese made CNC plasma table   
   >to an American made plasma cutter. After I figured out that the   
   >"partial pressure" the Chinese manual mentioned was in reference to a   
   >built in jumper selectable voltage divider  I was able to get the two   
   >machines talking to each other and everything works now. But the   
   >Chinese manual shows a filter on  a sense wire and I don't know   
   >exactly what to do about it. The sense wire is connected to the copper   
   >shield on the plasma torch and to a terminal in the CNC control. The   
   >machine uses the shield to sense the work. The machine moves the   
   >plasma torch down until the shield contacts the work and then moves   
   >away a set amount and energizes the plasma torch. I think, but am not   
   >sure, that the control can now sense the distance between the work and   
   >the torch tip, so that if the work is warped and rises or falls the   
   >torch will follow the contour of the work. In any case, the connection   
   >diagram for this sense shows it being wrapped a few times through a   
   >ring. And somehow the manual alludes to this ring as being some sort   
   >of filter. Since the neighbor didn't have any type of ferrite rings I   
   >just wrapped a few turns of the sense wire through a few insulated   
   >washers just to see if I could get the machine to work. And it did.   
   >Well, I dug  a ferrite ring out of a bad switching power supply and   
   >removed the coiled wire from it. I'm hoping I can just duplicate the   
   >washers trick with the ferrite ring but I'm thinking that I need   
   >advice on how many turns of wire through the ring I should use. I   
   >know, there are many different types of ferrite and I have no idea   
   >what kind mine is. And there must be a bunch of other variables as   
   >well. But if I can at least not ruin anything it would be great.   
   >Thanks,   
   >Eric   
      
      
   You did not mention any problems WITHOUT the choke.   
   So it might work anyway and your ring does nothing to it.   
      
      
   A choke is usually wound with five to ten turns   
   around a ferrite.   
   Its performance can be measured, but that was not your question.   
      
   w.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)