Re: DTSSTC electrolytics for performance?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: fucian@xxxxxxx 

 How does one calculate the bang energy?Ive always wondered this and 
just now mustered up the courage to ask :-D
Is it power drawn divided by BPS or something?
Thanks!
Matt

-----Original Message-----
From: Tesla list <tesla@xxxxxxxxxx>
To: tesla@xxxxxxxxxx
Sent: Wed, 10 Aug 2005 12:22:23 -0600
Subject: Re: DTSSTC electrolytics for performance?

Original poster: "colin heath" 
<<mailto:colin.heath4%40tiscali.co.uk>colin.heath4@xxxxxxxxxxxxx>

I personally dont think losing 10V on each cycle is too bad, but 20V
would be a bit much in my opinion, since the second bang will be that
much lower in energy. Doubling the cap to 3000uF is a perfectly fine
idea in my opinion ;-). Lets the IGBTs go with more of a bang too!

hi steve,
  many thanks for the great example and ill go work it all out now 
but i think i will up it anyway as the stud spacings are the same.
ill report any findings in performance gain from this at higher break rates.
many thanks
colin heath
----- Original Message ----- From: "Tesla list" 
<<mailto:tesla%40pupman.com>tesla@xxxxxxxxxx>
To: <<mailto:tesla%40pupm>tesla@xxxxxxxxxx>
Sent: Tuesday, August 09, 2005 11:08 PM
Subject: Re: DTSSTC electrolytics for performance?

>Original poster: Steve Ward 
<<mailto:steve.ward%40gmail.com>steve.ward@xxxxxxxxx>
>
>Colin,
>
>You can get an idea of how insufficient a supply capacitor is by first
>figuring out how many joules your coil uses in 1 bang. Now, you can
>calculate the lytic storage energy by .5C*V^2. Once you know the bang
>energy, subtract it from the lytic energy. Then devide this new
>energy by .5C, and then take the sqrt of that, giving you the voltage
>remaining on the capacitor after just the 1 bang.
>
>I will make a theoretical example of your coil, assuming it draws say
>1kw at say 200bps, thats 5j a bang.
>
>Energy in a 1500uF 350V cap : . 5(.0015F)(350v^2)=~92J
>Energy left in cap after bang : 92J - 5J = 87J
>Voltage in cap at 87J : sqrt(87/.5C) =340.6V
>
>But since you hit the cap twice between recharging on the mains cycle,
>you lose that energy again (and repeating the above calculation, but
>assuming 340.6V now) you are down to about 330V on the caps.
>
>I personally dont think losing 10V on each cycle is too bad, but 20V
>would be a bit much in my opinion, since the second bang will be that
>much lower in energy. Doubling the cap to 3000uF is a perfectly fine
>idea in my opinion ;-). Lets the IGBTs go with more of a bang too!
>
>Steve Ward
>
>On 8/9/05, Tesla list <<mailto:tesla%40pupman.com>tesla@xxxxxxxxxx> wrote:
> > Original poster: "colin heath" 
<<mailto:colin.heath4%40tiscali.c>colin.heath4@xxxxxxxxxxxxx>
> >
> > Hi All,
> > On my second DRSSTC i only use a very small electrolytic
> > 1500uF at 350V. im just wondering if i would benefit in spark length
> > by going upto 3000uF?
> > would the best way to check this be to measure DC Buss voltage and
> > see if it sags at full power with various breakrates?
> > many thanks
> > Colin Heath
> >
> >
> >
>
>