NSTs and Cap Charging.

To: tesla-at-pupman-dot-com
Subject: NSTs and Cap Charging.
From: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz> (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Fri, 09 Apr 1999 11:53:13 -0600
Approved: twf-at-verinet-dot-com

Further to the discussion on resonant charging, I decided to run 
some figures through the mill to see whether one really could do 
better than the VA faceplate rating. NB - this is not modelling, 
just looking at the calculations. For this purpose, I've assumed that 
the experimentally determined value of cap that appears to give best 
results is 2x the resonant value and gets charged to SQRT2*Vrms. I've 
further ignored the consequences of opening the gap up to 2.22*Vrms 
for the resonant case.

A typical transformer: 12kVrms, 60mArms, Fmains = 50Hz, BPS = 100.

VA rating = 720

Case 1: resonant charging

Based on V/I = Zcap, Cp = 15.92nF
If gap is set to 26.64kV (assume no losses), then Ec = 5.65J roughly
so power = 565W, less than the VA rating.

Of course one wouldn't normally open up the gap to this extent so one 
might assume that you get firing at 2Fmains at  Ec = 2.3J which means 
a throughput of 460W or so.


Case 2: larger capacitor

Let Cp = 32nF and assume it charges to 17kV in a half cycle. 
Then Ec= 4.62J and throughput = 462W.

In neither case is the VA rating of the transformer exceeded.
Comments? Flaws?

Malcolm