Re: New style nst's

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

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

In a message dated 12/4/01 1:52:19 PM Central Standard Time, tesla-at-pupman-dot-com 
writes:

<< Hi guys!! While i have quite a few older nst's, i picked up some of the 
newer 
 ones.Ventex claims 3.2 to 6kv at 30ma output for these guys. Weighing in at 
 less than one pound,their older brothers well over ten how is this power 
 possible?While it will "light" neon,you can not draw an ark from it.If this 
 is a safety factor can it be overcome?Keep the list coming!! Thanks
                                                           john in nyc >>

Hi John,

What you have there is a high frequency neon power supply. The weight and 
size savings comes from using a higher frequency to drive a small lightweight 
transformer inside the power supply. The power supply consists of a 20 to 30 
kHz oscillator that drives a ferrite core step up transformer. All Iron can 
be eliminated from a transformer designed to operate at higher frequencies, 
and that saves a lot of size and weight.  

Most neon power supplies have built in circuitry to halt their operation if 
there is no load (or an improper load) on the output. This is to remove 
voltage from the sign in case a tube gets broken or something shorts out. It 
also keeps the voltage coming out of the power supply from getting too high 
and destroying the transformer. I doubt if this feature could be defeated, as 
most of these power supplies are potted in epoxy. Even if you could, doing so 
would probably destroy the transformer. 

These are electronic (semiconductor) devices and will not stand much undue 
punishment, like running a Tesla coil. Also, they are made to run a resistive 
load (neon) with a minimum of capacitance in the circuit. Probably not of 
much use in a TC, but great for neon.

Tony Greer
Special Effects Neon
Lubbock, Texas

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