Re: blown NST's

[Megavolt121-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Richard
    Ross O uses his "1/2 NST" that is unpotted. Occasionally it can be seen 
spitting out some oil/tar goo that wasn't removed during his depotting. His 
site can be seen at http://users.better-dot-org/roverstreet .
    I have also depotted an NST(which i recently gave away). I first melted 
out the majority of the tar on my bbq grill. After that I used a dremmel 
combined w/ a big hammer and chisel to cut off one of the long sides and then 
went in and cleaned out more tar to free up the core and windings. from 
there, i cleaned more and soaked the sucker in gasoline for a few days before 
doing more cleaning. I did the soak and clean method a few times. Since gas 
rates were sky high when i did this, i didn't change the gas each time i 
resoaked since it was about 3 gallons of gas (and i didn't have anywhere to 
throw the gas away at). What you have to watch for is not to cut your fingers 
on the sharp metal and not to get high on gas. good luck
-Alan


In a message dated 9/6/00 1:47:53 PM Pacific Daylight Time, tesla-at-pupman-dot-com 
writes:

<< 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.
  >>