Re: [TCML] First light new secondary

[Miles Mauldin <teslamiles@xxxxxxx>]

Hi All,
 
Well that was easy to find.  I had one dead NST, both sides.  It was the odd one 
in the bunch being a Eurocom and the rest are Transco.  Think it was a poor NST 
to begin with, or maybe I did something to destroy it?  
http://www.cmnow.com/TeslaMan/1stLight/1-dead.JPG
 
Everything went well last night, though I did make a couple of changes.  I 
noticed my RQSG electrodes were not aligned properly anymore, and I'm guessing 
that they moved due to heat and vibration.  Was that the possible cause of the 
one NST's demise?  Anyway, I changed the RQSG out with my new SuckerSG, and that 
worked very well.  I kept the gap at about .2".
 
I found my tap point for tuning to be exactly where I experimented in JavaTC, 7 
turns. A whole turn different either direction really made a significant 
difference in output arc.  However, a quarter turn either side of 7 turns was 
almost unnoticeable in output performance.  

 
http://www.cmnow.com/TeslaMan/1stLight/
 
So I do have a couple of questions.  I roughly measure 30” arcs with a breakout 
point using the 12000/90mA setup with 30nF of tank capacitance and a .2” SSG.  
The Terry Filter never fired once (unlike the night before when it did fire 
several times).  

 
What are my options to increase performance?  Can the gap be widened without 
much risk if the Terry Filter is properly adjusted?  JavaTC calculates my top 
load to be 19.796 pF, which seems right to me based on the input power.  Will 
more capacitance produce longer but fewer arcs?  Am I down to the point of 
adding more current to the primary circuit as being the only option?
 
I’m not looking for the longest arc but I am looking for better overall 
performance.
 
Thanks to all of you who have helped me along to this point.
 
Miles



________________________________
From: Bert Hickman <bert.hickman@xxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Thu, October 21, 2010 11:10:46 AM
Subject: Re: [TCML] First light new secondary

Hi Miles,

Congratulations and condolences... :^)

Try disconnecting the Terry filter to see if you get any output from the 
NST bank. If not, one of the NST's may have failed - this can draw 
current from all the others, killing output for the entire bank. Your 
strategy of testing each NST individually to locate the defective one(s) 
will work. It is NOT likely that you killed all four, but it might be 
possible that you killed different halves of two of the NST's.

Good luck!

Bert

Miles Mauldin wrote:
>Even with everything disconnected I can't
> draw an arc on the NSTs. I have 4 x 12/30 on parallel for a total of
> 12/120. Could I have really killed 4 NSTs?
>My setup is a 4.125" secondary with 25" of 23AWG for 975 turns. K of
> .125. 4 x 12/30mA for 120mA total. A blown RQSG with 30nF tank. Total
> gap is .21.
>
> Clues? Suggestions? Comments?
>
> Best Regards, Miles
>
>
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