Re: Pushing Neons (fwd)

---------- Forwarded message ----------
Date: Sun, 26 Jul 1998 09:43:31 -0600
From: "D.C. Cox" <DR.RESONANCE-at-next-wave-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Pushing Neons (fwd)

to: Terry

It is very likely you would loose a few NST's by using these procedures. 
If you unpot them, drop them into a plastic tank filled with xmfr oil, then
they have better insulation and also cooling protection for the high
currents.  With a bit of chattering to the manufacturers you can obtain the
coil-core assemblies before they pot them and these work great for oil
immersion.  An even better solution is to go for the hard block epoxy
potential xmfr delivering 14.4 kV and use external current adjustment. 
These units are nearly indestructable in normal Tesla service.


> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Pushing Neons (fwd)
> Date: Saturday, July 25, 1998 10:35 PM
> ---------- Forwarded message ----------
> Date: Sat, 25 Jul 1998 17:53:00 -0600
> From: terryf-at-verinet-dot-com
> To: tesla-at-pupman-dot-com
> Subject: Pushing Neons
> Hi All,
>         I have been playing with a high performance charging circuit
> that uses a 15kV 60 mA neon transformer.  I have the design ironed out so
> that when the input voltage is 120 volts, the current is about 8 amps. 
> output voltage is 15kV and the current is 60 mA (all RMS values).  This
> charging a 20nF cap to 21 kV peak.  So everything is within
> of the components.  
>         The first problem is when the gap fails to fire or you are
> up the variac and the gap hasn't fired yet.  Without the gap firing, the
> neon's input current is 20 amps.  The output voltage is still 15kV but
> output current is 115mA.  These levels would be maintained only a short
> period of time (several seconds).
>         The second concern is that there can be turn-on transients of 30
> amps peak (only one cycle) on the input.  The output may see a 250mA peak
> for one cycle and a 35 kV output peak. 
>         The output transients don't worry me because the gap (or safety
> or transorbs) will fire and the system will startup.  The voltage and the
> current spike is only for one cycle.  Also this transient case is rather
> unlikely to occur often.  I am more concerned about the first case where
> high input and output currents my be sustained for several seconds.
>         My question to those that have "been intimate" with the internal
> parts of neon's is do you think these short term over currents will do
> harm?  
> Thanks,
>         Terry Fritz
>         terryf-at-verinet-dot-com