Re: NST blown

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

Original poster: "Hydrogen18" <hydrogen18-at-hydrogen18-dot-com> 

http://home.att-dot-net/~allencoilpage/xformproj.htm

for rebuilt transformers

Btw, welds can be ground out with any half decent angle grinder. Check the
local flea market. I got one for $8. It does 10k rpm, but lacks torque
control so actual working rpm is probaly more like 6 or 7 thousand rpm.
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, January 28, 2004 6:19 PM
Subject: RE: NST blown


 > Original poster: "Randy & Lori" <rburney6-at-comcast-dot-net>
 >
 > If I understand correctly you measured for ohms from one HV terminal to
 > the other and found that you were open.  The reason that you still get
 > some kind of spark when you plug it in, is that there are actually 3
 > coils in the NST.  There is the primary that is plugged into the outlet,
 > and there are two HV coils that are center tapped to ground.  Each of
 > the HV coils will put out 4.5KV against ground, and 9KV against each
 > other.  You have only let the smoke out of one of the two HV coils.  If
 > you measure each HV terminal against ground, I believe you will find
 > that one is fine and that the other is open.  For your second question:
 > To actually repair the coil itself is next to impossible.  The wires are
 > as thin as a hair, and you have no idea how far into the coil the break
 > is.  If you were to unpot the transformer, and you had another HV coil
 > to put in it's place, then that may be possible.  I recently opened a
 > 12/30 and found that the core was welded, unlike my 15/30 which was
 > bolted(one more obstacle).  Sorry to be the bringer of bad news.
 >
 > Randy
 > Savannah, GA
 >
 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: Wednesday, January 28, 2004 10:14 AM
 > To: tesla-at-pupman-dot-com
 > Subject: NST blown
 >
 > Original poster: Bob81818-at-aol-dot-com
 >
 > Hi all, I was demonstrating my first coil at school and after running it
 >
 > for a few minutes (not continuously) the spark gap stopped firing after
 > taking it home the secondary of the 9/30 nst had no conductivity, so I
 > just
 > implied that it destroyed itself. I plugged it in to double check and I
 > got
 > less than millimeter sparks when I scraped a wire over the two secondary
 >
 > electrodes. That kinda puzzled me a bit, would appreciate if someone
 > could
 > explain how that happened if the sec is blown. And I was also wondering
 > if
 > its possible to fix an nst like this. I'm not surprised that I blew the
 > xformer cuz I didn't ground the tank circuit, or put in a safety gap, I
 > guess I just wanted to know if the coil would work before I added all
 > the
 > safety stuff, therefore I accept that I am an idiot. A little advise on
 > this subject would be nice.
 >          Thanks all,
 >                Dan
 >
 >