Re: RQ gaps was -JF efficiency theory (again)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Mddeming-at-aol-dot-com>

In a message dated 2/18/01 11:06:29 PM Eastern Standard Time, 
tesla-at-pupman-dot-com writes: 


>
> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" < 
> Tesla729-at-cs-dot-com>


snip--- 
The question I have is 
 has 
>
> anyone else noticed browning of the PVC pipe support between 
> the copper tube spark gap electrodes, where the sparks blaze 
> against the PVC? I've heard that PVC is susceptable to UV radi- 
> ation and I've noticed that the browned areas are electrically 
> weaker and tend to want to flashover more than the unstained 
> areas of the PVC. BTW, I was running (3) 15/30s in parallel with 
> an 18 nFD primary cap. The gap worked good at quenching the 
> arc for a couple of hours of continuous operation, but after a while 
> it started giving some problems due to this discoloration of the 
> PVC between the SG electrodes (namely, a loud flashover that 
> crawled over the surface of the discolored area of the PVC between 
> the electrodes, and can be heard over the regular SG sound). I 
> was just wanting to see if any of the other coilers had noticed this 
> effect. 
>
> David Rieben 


Hi Dave! 
        It's possible that the "stain" is microscopic particles of copper 
and copper oxide deposited by vaporization of the outer surface of the gap 
tubes at the arc point during prolonged runs. The spark's point of contact 
can get extremely hot even if the overall tube temperature is not. 

Matt D.