Re: chokes

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Ed,

At 07:54 AM 10/4/2001 -0700, you wrote:
>> Hi Greg,
>> On this subject you will find as many opinions as there are "Biological 
>exhaust
>> systems" (Everybody's got one.) To my knowledge, no one has done a
long-term,
>> controlled, comparison study in coils identical except for filter chokes. 
>Most
>> evidence is anecdotal-- ("Such-and-such seems to work for me, it must be
>> right.") The cost of such a comprehensive study would be beyond the means of
>> most Coilers, since it requires a statistically significant number of
>> transformers to "run to failure". Perhaps the Geek Group could undertake 
>such a
>> project. For now, this is still an experimental science.
>> 
>> Matt D.
>
>	Network simulation is not experimental, and the results are valid.  It
>is obvious that a lot of chokes that have been described here would do
>nothing at all, and therefor at best be harmless.  Terry is correct and
>chokes are a waste of time.  Resistors will do more good, backed up with
>the MOV's or plain safety gap directly across the NST secondary.  
>
>	One useful contribution to general knowledge here would be for someone
>to go to the trouble of trying to model the outer layers of an NST
>secondary and then determine current and voltage distribution during a
>discharge.  Can surely be accomplished by modern modeling techniques,
>but I don't know how to do it.
>
>Ed
>

I don't know how to do it either...  The high voltage on the outer windings
"thing" is an unproven theory.  Failed NSTs do seem to blow on the outside
winding.  That is also a high voltage gradient area without any doubt as
well.  The inductance of that outside layer combined with the say 300kHz
can drop a lot of voltage on the winding but there also needs to be a place
for the current to flow which would have to be from inter layer capacitance
I would think.  Judging from how complex the secondary has been shown to be
from Paul's work, I bet this is far worse to model.  

However, if one had a secondary winding exposed, a signal generator, and a
high impedance scope probe...,  one could inject a say 300kHz signal into
the winding and measure the voltage drop.  That would give a very good idea
as to what proportion of an incoming signal gets dropped into the outer
winding.  A good thing for that half blown depotted NST sitting on the shelf.  

I have the generator and the scope stuff but since I use protection filters
I don't have any blown NSTs :o)))
If anyone has a spare old NST winding they could send me, I could give it a
test (terellf-at-qwest-dot-net ;-)).  I could figure out a temporary core to stick
in it so only the single NST winding itself would be needed.  I would have
to scratch into the wire to make contact so it may ruin the winding.

There is also a nasty high voltage spike at the beginning of gap condution
that is rich in up to GHz harmonics, but will will just try crawling first ;-))

Cheers,

	Terry