Re: Looking for an 18KV distribution arrester

["Tesla list" <tesla@xxxxxxxxxx>]

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

Here's a quick picture I just snapped of one of the
21kV Ohio Brass arresters sitting on top of a pole
pig:
http://silicon-arcana.com/tesla/arrester.jpg

Got a bunch more, too.  It's too bad they weigh as
much as a good-size PT each or I'd be happy to hand
'em out.  If anybody's in the Seattle area and needs
one...

Cheers,
Aaron, N7OE

--- "J. Aaron Holmes" <jaholmes@xxxxxxxxxxxxxxxxxx>
wrote:

> Fascinating.  Yes, the 3kV ones are by Kearney, but
> I
> too broke one open (literally--with a sledgehammer)
> and I didn't see such a thing.  All I saw was a
> silicon carbide disc about 1.5" long and 1.5" in
> diameter with spring-loaded contacts to hold it in
> place.  Could have missed something in the rubble,
> though! ;-)  Unfortunately, this was years ago and I
> didn't take any pictures.  I played with one using a
> 15/30 NST and variac and found that I could hear a
> faint buzzing when the thing went into conduction.
> Seemed to work great.
>
> I've heard of explosive charges being used in fuses,
> but not in arresters.  That is interesting.  I may
> have to break another one open now! :-))  Of course,
> if there's rim-fire ammunition in there, a
> sledgehammer may not be the best tool to use this
> time!!! :-O
>
> The larger 21kV units are all MOV+gap types, I'm
> pretty certain.  I've got a couple of units made by
> Ohio Brass (Type GP Series 3 "Dynagap"--can't find
> any
> literature on them, unfortunately), and a couple by
> McGraw Edison units (buried under a bunch of junk
> now,
> or I'd cite the model#).  I did at one point find
> literature for the McGraw Edison ones, and it had a
> nice cutaway diagram of the innards, which employed
> no
> explosives IIRC.  I've lately acquired a 24kV PT,
> but
> haven't tested these larger arresters yet.  I need
> to
> do that!  Should be fun :-)
>
> Regards,
> Aaron, N7OE
>
> --- Tesla list <tesla@xxxxxxxxxx> wrote:
>
> > Original poster: FIFTYGUY@xxxxxxx
> >
> > In a message dated 4/28/07 7:56:22 P.M. Eastern
> > Daylight Time,
> > tesla@xxxxxxxxxx writes:
> >
> >  >I've also got a dozen or so 3kV
> >  >ceramics the size of soda cans.  These latter
> ones
> > are
> >  >brand new in boxes with mounting hardware.
> >
> >      Those wouldn't happen to be the "Kearney"
> > arrestors, would they?
> > A local surplus buddy of mine gave me one to check
> > out. 3kV, new in
> > the box with hardware. He has a bunch.
> >      I've posted this before, but I'll say it
> again:
> >
> >      I dissected one of those 3kV Kearneys, after
> I
> > tested it with a
> > NST. Did its job with the NST across it. However,
> > when I dissected
> > it, I found a .22 LR blank was designed into it. I
> > presume when the
> > current level gets high enough, the blank is
> > supposed to blow the
> > endcap off the thing and quench the arc.
> >
> >      So be careful how you mount those.
> >
> > -Phil LaBudde
> >
> >
> >
> >
> > ----------
> > See what's free at
> >
>
<http://www.aol.com?ncid=AOLAOF00020000000503>AOL.com.
> >
> >
> >
>
>