RE: NST Life Expectancy

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

Original poster: "Lau, Gary by way of Terry Fritz <teslalist-at-qwest-dot-net>" <Gary.Lau-at-hp-dot-com>

A properly constructed "Terry filter" includes safety gaps that have been 
adjusted to fire just over the NST's open-circuit voltage, and a string of 
MOV's.  Did your filter have these elements?

Your statement that "my new RQ gaps were opened full.." would seem to 
indicate the cause of the problem.  Safety gaps and MOV's are like speed 
limit signs and speed traps, and opening the gaps is like putting the gas 
pedal to the floor.  Live fast, die young.

The water condensation may be a by-product of the fire resulting from your 
NST's internal arcing, or it may be a remnant of a harsh pre-coiling life 
in an outdoor sign, difficult to say now.  If the latter, this may have 
been a factor in the unit's early demise.

Gary Lau
MA, USA


Original poster: "WIZZARD . by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
<pbobyk-at-hotmail-dot-com>

My 4" coil and had one of the NST's die.
I suspect my protection circuit was the cause.
I made a Terry filter and put it on my remaining NST.
I believe the second transformer has now failed.
I'm new to this game but I think a transformer should last more than a
couple minutes of operation.
What is the normal life expectancy of an NST?

The second 15KV/30mA transformer was doing great. The coil was tuned and my
new RQ gaps were opened full..
I could hear some internal arcing inside the NST case and could smell a
burning smell.
I pulled the top off the transformer immediately and some smoke/steam came
out as I lifted the cover.
I could see the tar had cracks just like the last one that failed. This
time there was a small hole where what looked like water had condensed
around. The liquid was also condensed on the top that I lifted off. The
transformer case was quite warm if you grabbed the case.
What is happening?
How can I stop this.

A quickly going broke coiler... LOL!

_