Re: Revolution in coil design

To: tesla-at-pupman-dot-com
Subject: Re: Revolution in coil design
From: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz> (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Wed, 28 Apr 1999 17:07:55 -0600
Approved: twf-at-verinet-dot-com

Hi Nick,
         a couple of ccomments:

> Original Poster: NickandSim-at-aol-dot-com 
> 
> Hi All, 
>          sorry about the overly dramatic title but this may just justify it.
> I think that it may be possible to push tesla coils up to much higher power 
> levels without the increase in capacitance that normally makes this such a 
> pain.
> The actual power throuput of a tc system is determined by the break energy 
> (the energy stored in the capacitor  when the spark gap breaks down) 
> multiplied by the break rate in bps.
> 
> A hypothetical small coil has a break energy of 0.25J with a 0.0141|F cap
off 
> a 6kV neon.  At 100bps (a static gap off 50Hz) that is 25W of real power
into 
> the primary.
> 
> If we use a rotary gap an push it up to 500bps then the power is up to 125W.
> 
> There are problems with the over simplified scenario above 500bps would fry 
> the neon and the neon's high impeadance would prevent it from charging 
> properly at the higher break rate.  
> If we use a system fed by two MOTs rectified (6kV -at- 0.5A) then we have more 
> than ample power.  Some of you will say 'but surely the cap will not 
> discharge fully' an LC osscillator is a great example of exponetial decay.  
> After one cycle it is down to 50% of the starting voltage then 25%, 12.5%
and 
> so on in a lovely asymptotic curve.  So by cycle 5 there is vitually no 
> energy being fed in anyway.  Which in a medium sized system would have taken 
> 50|s - a lot faster than even a rotary gap can quench.
> 
> Basically what I am saying is that you can simply up the power by increasing 
> the break rate - as long as your psu can take it.
> 
> Anything that simple has to be wrong somewhere - tell me if it is.
> 
> Nick Field    
> 
> P.S. I am planning a system based around this idea which may just be running 
> (at 800W) for the teslthon - see you there.

All true, but there are other factors. First off, an increase in BPS 
adds to capacitor stress so ratings are important. Secondly, an 
increase in BPS doesn't buy an increase in output voltage or 
available terminal charge per bang.

Malcolm