Re: Geek Pig! :)

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

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

In a message dated 1/22/01 10:54:39 AM Pacific Standard Time, 
tesla-at-pupman-dot-com writes:

<<  "Christopher Boden by way of Terry Fritz <twftesla-at-uswest-dot-net>" 
<chrisboden-at-hotmail-dot-com>
  
<Can the smaller (3"dia X 10"L) 12kV arrestors be used for protection of the 
<Pig?
<Do Pigs NEED protection? The Lightning arrestors we have are all rated at 
<12kV, but the Pig is rated at 13.8 and I KNOW the arrestors were hooked up 
<to it when in service. What is the actual firing voltage of the arrestor? 

Chris, all,
I use a 12 kV rated lightning arrestor in parallel with the output of 
my 10 kVA, 14.4 kV pig to the Tesla tank circuit. Then the pig is
slightly overdriven with up to 280 volts input from the 0 to 280 volt/
28 amp rated variac. The arrestor works good up to about 85 on the
0-100 scale dial of the variac, then it starts clipping the output of the
pig, as it's doing what it is supposed to do. From hi-pot testing it, I
would say that the arrestor doesn't actually start to shunt the over-
voltage to ground till the HV potential reaches around 15 to 17 kV, 
although it is rated at 12 kV on the label. Remember, these arrestors
are designed to only shunt serious overvoltages to ground (like a 
lightning strike on the power line), which, in my opinion, is great for
pig powered Tesla systems as a safety gap substitute. And the pig
is designed to take serious overvoltage surges without dying and if
the surges get dangerous high, even for the pig, that's where the ar-
restor takes over.

<< Does anyone know the internal construction of the arrestors? >>

It's my understanding that they are basically an appropriate number
of  HV (1800 volt?) MOVs in series. I know from experience that they 
don't burn out once they are called on to shunt an overvoltage peak. 
Once the voltage returns to normal operational levels, they are as good 
as new.

David Rieben