Re: blown NST's

["TruckDrivingMan" <Tom.Ansorg-at-t-online.de> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi
You may not use NSTs with a RSG.You have to put a safety (static) gap
parallel.I don't exactly know why,but consider it as a matter of fact

Tom

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, September 07, 2000 3:59 PM
Subject: blown NST's


> Original poster: "Richard Barton" <richardbarton-at-caving5.freeserve.co.uk>
>
> Hi all
> For around 4 years I've used 3 NST's (12/30 each) hooked up
> in parallel, using a static gap, with no problem. Recently I build a
rotary
> gap..... now all three NST's seem to have blown !
> They are all shorting to the metal case internally.... one of them has a
> real bad DEAD short, and knocks the trips out immediately.
> The other two seem to knock the trips out after a minute or so, they
> have a fairly high leakage to the cases, but it's not a dead short.
> Now, I've read all about this business of de-potting NST's, but these
> ones seem to be potted in resin ! At least , it looks like resin to me.
> It's very hard to even scratch, and the stuff is a pale yellow colour, so
> I reckon it's impossible to de-pot these. They are "RICCI" units.
> Can someone confirm that these are resin-potted ?
> Further to this, if I can't de-pot these, is it not possible to used them
if
> I
> either-
> A. Use them without the cases earthed (Dangerous ?)
> or....
> B. Cut the cases off with tin-snips, and peel the metal off (Also
dangerous
> ?)
> These units are housed inside a cabinet, and could be mounted on rubber
> mountings to isolate them from ground, thereby getting rid of the tripping
> problem, but will they work properly if they are not earthed ?
> Richard Barton.
>
>
>