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Re: 10KV RMS -at- 300MA


From: 	FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
Sent: 	Thursday, June 26, 1997 12:51 PM
To: 	tesla-at-pupman-dot-com
Subject: 	Re: 10KV RMS -at- 300MA

>snip>
> I believe that by attempting to run at higher break rates the resonant
> charging is somehow screwed up. So far I have not figured out a way to
> look at the transformer output, but I would bet it is strange when the
> break interferes with the resonating.
 
If the resonant charging is screwed up, wouldn't this lower the capacitor
voltage?  More below...

>To answer a couple of the other questions:
 
> 1. I do not use any kind of ballast. These trannies are current limited
 
> 2. The output voltage does not sag...at least the reading on the
> rectifier meter that I use to monitor it does not change. The gap always
> breaks down at 10kv when I run the input voltage up.

The rectifier meter may be giving incorrect results?   

> 3. I am using the tightest coupling I can. Any more and I get racing
 sparks. 

> 4. Higher cap values increase the input current (to over 30A) but have
> little influence on spark length. Lower cap values (lower than .08uf)
> make the input current lower and the tranny output voltage goes lower
> and the spark length decreases. I have tried various k factors and
> various numbers of turns in the primary. I have also varied the top
> loads over a fairly large range. My original .081uf primary cap seems to
> be best for maximum spark at lowest input currents.

The larger cap values may be "shutting down" the transformer...like when
using a too-large cap in a neon system?

As I mentioned, the higher break rate doesn't help my potential 
transformer-driven TC either.  I assumed that my caps are not 
charging up to as high of a voltage...it seems to me that if the 
caps are reaching the same voltage at the high break rate, as at
the low break rate, then the TC would HAVE to give longer sparks. 

You're probably right about the resonant changing being affected...it 
seems to me that resonant charging takes time...more time =more
voltage.  If we discharge too soon, the cap will not have time to 
"resonant up" to the higher voltage.  I noticed that my spark gaps had
more trouble firing at the high break rate, and I had to adjust them 
closer, (I'm using 8 to 12 gaps in series in the rotary).  

My suggestion;  measure the cap voltage using a EHT probe and scope as
recommended by Malcolm.  

John Freau


 
> Still perplexed in Detroit, USA
 
> Skip Greiner
  >>