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HV coax?




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From:  Bill the arcstarter [SMTP:arcstarter-at-hotmail-dot-com]
Sent:  Monday, May 11, 1998 10:29 AM
To:  tesla-at-pupman-dot-com; dr.resonance-at-next-wave-dot-net
Subject:  HV coax?

It was written:
>>From:  D.C. Cox [SMTP:DR.RESONANCE-at-next-wave-dot-net]
>>Sent:  Friday, May 08, 1998 8:51 PM
>>To:  Tesla List
>>Subject:  Re: Pole pig HV wires (fwd)
>>
>>to: Brian
>>
>>Never use coax to transmit power from a pole pig to a Tesla 
oscillator. 
>>It's capacitance is just right to resonate with the secondary of the 
>>xmfr
>>and will produce severe overvoltages on the order of 150 kV.  Best to 
>>use a
>>single conductor wire such as spark plug wire or coax can be used if 
>the
>>outer ground braid is stripped away and not used at all.  Ground one 
of 

Can you go into more detail on this??  Is this a resonance between the 
cable and the xfmr, or is it s transmission line phenomenon??

Seems like the output impedance of a pig would be much less inductive 
than that of an internally-current-limited NST.  Thus this resonance 
would be less pronounced on the pig.  Am I deluding myself?

Recently we've been powering our coil remotely via two parallel 30 ft 
lengths of 100KV-rated x-ray coax hooked to the pig.  This stuff is 
nearly an inch o.d., and the insulation between the center lead and the 
outer ground is at least 1/4 inch.  We do notice some odd effects - such 
as thin wispy arcs off the far end of the cable...  We have the shield 
grounds attached to the frame of the pig (ground) on one end only.

BTW- modern commercial x-ray transfomers have a special circuit designed 
to dissipate the energy capacitively stored in the cable after the 
exposure is complete.  This is to prevent accidentally electrocuting the 
field service engineers...

Is the above resonance effect the "Blum Line" effect (which I've tried 
to research but can't find anywhere...)??
Thanks for your assistance!

-Bill the arcstarter
Starting arcs in Cinci, OH
http://www.geocities-dot-com/CapeCanaveral/Hangar/6160


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