Re: [Fwd: Spark gap not firing]

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

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Parpp807-at-aol-dot-com>

In a message dated 2/10/01 12:13:54 AM Central Standard Time, 
tesla-at-pupman-dot-com writes:

<< Hi John C.,
 
 There have been numberous discussions on these
 configurations as you know since you were part of them. I
 believe the consensus showed that the coilers who lost NST's
 in the cap||xfmr configuration were very real and that the
 gap||xfmr configuration was best for the reasons stated
 previously. In either configuration, if the NST does not
 have overvoltage protection gaps, then NST death is almost
 certain. I don't think we can adequately say that all these
 NST's died for the same reason. But, we can say that the
 addition of safety gaps and gap||xfmr configuration is less
 of a risk than the other.
 
 Take care,
 Bart>>
 
Hi Bart, John C., Terry,

This is a great class.
I have been playing with my bipolars for a little over two years, using a 
parallel
combo of two 15/60 NSTs, the classical cap-SG circuit, and no safety gap. I 
thought I knew it all.  :-)) Aware of the stresses on the NSTs, I have kept 
the runs short and the gaps set close for the 0.023 uF MMC. I have not blown 
a transformer--yet.  
Since the NST is current limited by the magnetic shunts, it is understandable 
that
a high frequency backfire can suddenly increase the impedance and drive the 
current
into a brick wall. When Bart told me about Terry's NST protection filter and 
the 
preferred use of the SG-cap configuration I got instant religion and 
installed the protection filter on what is now three NSTs for 15/150. I am 
still using the cap-SG circuit. So I assumed that all the classical diagrams 
in John's books and in Circular 74 assume the use of a non-current limited 
transformer like a pole transformer. Now, just when I thought I had reached a
little understanding, amazingly I do not understand why a
non-current limited transformer is also susceptible to damage from a high 
frequency
backfire. Is a non-current limited transformer at least less susceptible?

Very slooow learning taking place.

Happy day,
Ralph Zekelman