RE: Why does running an NST on an async gap kill it?

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

Original poster: "Jeremy Scott by way of Terry Fritz <teslalist-at-qwest-dot-net>" <supertux1-at-yahoo-dot-com>

I killed a 15/60mA NST like this once.

The teeny wires inside of the secondary aren't
designed for the hundreds of amps the capacitor
will throw into them if the spark gap fails.
More so if you've got a resonant cap.

That's where the big power resistors help in Terry's
filter circuit. Even so, it's hard to stop a thousand
amps -at- 21Kv :) The MOVs basically overheat and cease
to protect the NST in just a few seconds.


--- Tesla list <tesla-at-pupman-dot-com> wrote:
 > Original poster: "Lau, Gary by way of Terry Fritz
 > <teslalist-at-qwest-dot-net>" <gary.lau-at-hp-dot-com>
 >
 > The so-called Terry filter actually has two
 > functional components:
 > 1) The R-C (not R-C-L) filter forms a low pass
 > filter, attenuating high
 > frequencies.
 > 2) The MOV's and safety gap form a clamp to limit
 > the maximum voltage to
 > the NST.
 >
 > The R-C filter alone can't do anything to limit the
 > voltage in the event
 > that the gap is not firing.  The MOV's might help,
 > but they're not designed
 > to absorb too much energy, and they might burn out.
 >
 > Gary Lau
 > MA, USA
 >
 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: Thursday, August 07, 2003 11:38 AM
 > To: tesla-at-pupman-dot-com
 > Subject: Why does running an NST on an async gap
 > kill it?
 >
 >
 > Original poster: "Zagarus Rashkae by way of Terry
 > Fritz
 > <teslalist-at-qwest-dot-net>"
 > <arbitrarily_random-at-yahoo-dot-com>
 >
 > Hi All,
 >
 > I think I pretty much phrased the entire question in
 > the subject line :)
 >
 > Is there anything one can to to protect the NST from
 > damage? Wouldn't an RLC filter like a Terry filter
 > protect the NST from spikes?
 >
 > Thanks,
 >
 > Chris Lu
 >
 >