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Re: Looking for an 18KV distribution arrester
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
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
--- "J. Aaron Holmes" <jaholmes@xxxxxxxxxxxxxxxxxx>
> Fascinating. Yes, the 3kV ones are by Kearney, but
> 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
> literature on them, unfortunately), and a couple by
> McGraw Edison units (buried under a bunch of junk
> 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
> explosives IIRC. I've lately acquired a 24kV PT,
> haven't tested these larger arresters yet. I need
> do that! Should be fun :-)
> 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
> > 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
> > I dissected one of those 3kV Kearneys, after
> > 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