Re: NST power rating con

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

Original poster: Neonglo-at-aol-dot-com 

In a message dated 10/2/03 8:55:45 PM Central Daylight Time, 
tesla-at-pupman-dot-com writes:

>Original poster: Thomas <tom-at-pwrcom-dot-com.au>
>
>Ok, I can now see why there is a need to indicate the maximum secondary
>voltage and current even though both can not be supplied at the same time.


Exactly. Into a purely resistive load, a typical NST at 120 volts can 
supply 50% to 55% of it's secondary voltage rating, while delivering 80% of 
the rated current. This means that a 15kV/30mA NST is actually meant to put 
out about 7500 to 8250 volts at 24mA on a continuos basis when 'properly' 
loaded with neon tubes. (The tubing in neon signs is properly loaded by 
selecting a transformer which will supply 80% of it's current ratings into 
the tubes in that circuit.) Of course, adding capacitance to the circuit 
changes everything. Just running the high voltage wire through grounded 
metal conduit can add enough capacitance to cause numerous problems to an 
NST. It's no wonder they are so fragile in TC use with large tank caps. 
That's why safety gaps and a Terry filter are so important to the safe 
operation of an NST in a TC.
-------------------------------------------------
Tony Greer
Special Effects Neon
Lubbock, Texas