MOV lightning arrestor in place of safety gap...MCOV?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "J. Aaron Holmes" <jaholmes@xxxxxxxxxxxxxxxxxx>

Hi all,

I recently picked up a baker's dozen of 3kV MOV
distribution lightning arrestors on eBay for little
more than a dollar each.  Seemed like a steal; these
things are each the size of a soda can!  Ok, on to
practical matters:  How do I use them?  My intent was
to use a few of these in series in place of (or in
addition to) a safety gap for protecting my 15kVA
14.7kV pig.  Or as part of the world's largest Terry
Filter :D  Trouble is, I can't decide how many to put
in series.  Should I be going by the arrestor rating
(3kV), or the MCOV rating (2.55kV)?  Or maybe neither?
 I'm afraid I don't quite get why there have to be
multiple ratings on these things, but then I'm not a
power systems engineer.  Those folks are a little
strange (no offense! :D)  Maybe I should just put a
bunch of 'em across the output of my pig then rev the
variac up and down and keep removing arrestors until I
start seeing big currents on the input of the pig?
Hmmm...

I've heard of a few people using these in place of
safety gaps, but I haven't seen a lot of details.
Seemed like an interesting project, though.

Recommendations?

73,
Aaron, N70E