Lightning Surge Arrestors and MOVs

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

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

Hi all,
I'm going to bug you guys with another little question that
has been on my mind lately. As part of the safety gap sys-
tem of my pole pig driven Tesla system, I have employed
a 12 kV rated utility line lightning arrestor (the cigar shaped
porcelan insulator with one "line hot" lead on top and one
ground neutral lead on the bottom. I was wondering if this
device worked like the MOVs that you can purchase from
Digikey. I know from hi-pot testing of the arrestor that it safe-
ly shunts serious overvoltages above its rating to ground with-
out suffering any noticable damage to itself. It works pretty 
well with my 14400 volt pig, but as the pig is slightly overdriven
to up to 16800 volts from the 0-280 volts from the variac, it does
start clipping the output of the pig when I turn up the variac past
about 80 on its 0-100 scale dial. I was wondering if I could use
a sufficient # of the 1800 volt rated MOVs from Digikey in series 
for this same purpose or if I could just find I higher voltage rated
utility line lightning arrestor for this. Also, where can I get some
more of these lightning arrestors? I bought my current 12 kV 
rated arrestor froman individual vender at the Richmond, VA Tes-
lathon in ' 99 and I have no idea where he got it. I assume you 
could probably obtain these arrestors from companies that sale 
and rebuild pole pigs (T&R Electric,ect.). My local electrical utility
uses 7.2 kV and 13.2 kV primary line voltages, so their 13.2 kV
arrestors would probably still be a little low for my application. I
was thinking  a 16 kV to 20 kV rating woulk be about my target 
rating. 

Thanks,
David Rieben