Re: Ok, what is an LTR cap.

["Barton B. Anderson" <tesla123-at-pacbell-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Terry, Mark, 

Tesla list wrote: 
>
> Original poster: Terry Fritz <twftesla-at-uswest-dot-net> 
>
> Hi Bart, 
>
>         A 14.4kV 694mA pig should deliver 10000 watts.  If we divide 10000
> watts 
> by 120 BPS we get the energy per bang as 83 joules.  The peak voltage is 
> 14.4 x SQRT(2) = 20.4 kV peak.  So what size cap when charge to 20.4 kV 
> will hold 83 joules?

14.4kV x .694A = 9,994W (10kva). The peak is 20.4kV. But, 83 joules? How long
do you think it's going to take to charge a .401uF cap? Well, 41.8ms. At a BPS
of 120 (8.33ms), it would take more than one revolution using an 1800 RPM sync
gap with 1 eletrode. Well, slow the RPM's down and yes, but this isn't
realistic nor is this "impedance matched" to the transfomer. To "impedance
match" the cap to the rated transformer, I've been taught 1/(2*pi*Z*F), or in
this case, 0.128uF. I don't understand how .401uF (or .351uF) sounds perfect?
Getting really confused with this concept, and that's how I see this, as more
of a concept that's unrealisitic. Of course, I guess if we ran at 120 BPS
anyway, we would be down to 33 joules due to the cap only charging to 1 time
constant or so, but I'm not sure of the point here. How many coils can handle
33 joules? 

(confused with this in sunny CA), 
Bart 
>
>   
> E = 1/2 x C * V^2  or  C = 2 x E / V^2 
>
> C = 0.401uF  Assuming losses eat some of that up the 0.351 number sounds 
> perfectly correct. 
>
> However, pole pigs can be ballasted in all kinds of ways so you would have 
> to look at the total system to be sure the the equations would apply to a 
> pig system. 
>
> Cheers, 
>
>         Terry 
>
> At 06:35 PM 8/24/00 -0500, you wrote: 
> Hi Mark, Terry, 
>
> Tesla list wrote: 
> Original poster: "Mark Broker" <broker-at-uwplatt.edu> 
>
> > Actually, PIG's are STR's (smaller than resonant). Typically, coilers use a
>
> > 10kva, 14.4kv pig's. Resonant caps are 0.128uF (from memory). Obvisouly 
> HUGE! 
> > We typically use smaller than resonant caps (STR's) on our systems. NST's 
> > however (and OBIT's), can use LTR's. Could you imagine the joules for a pig
>
> > using an LTR? I see smoke, fire, wooosh!!! Well, for most of us, not Greg, 
> > Bill, Hull, etc... or you Chris (yet?). 
>
> Actually, Terry's MMC Calc gives me .351uF. 
> For a 240/14.4kv, 694mA, 20,749 ohm pig? Terry is .351uF correct? I though 
> a matching reosnant cap size should be 0.128uF. Maybe my math is wrong 
> here. Someone please clarify? 
>
> Bart 
>  Chris and I have a design, and are 
> attempting to gather enough caps (912 of Terry's, or any other combo that
> will 
> work).  Did you know that there's a world-wide tantulum shortage?  I even 
> have the 
> PC board mask already laid out (I think). 
>
> I thought that it was really 13.8kV nominal? 
>
> Mark