Re: Calculation of tank cap

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Herwig -

Yep, the resonant size on the pig is simply the most basic calc. In
reality, I wouldn't pfc the pig
anyway. I just happened to have notes around on measurements I made (open
load current), so it was easy
to use as an example to show how far off the method would be. I was
actually checking NST's when going
through the math, and the numbers were way off as well. The pig
"measurements" were handy, so I used it
only as an example.

Take care,
--
Barton B. Anderson
http://www.classictesla-dot-com

Tesla list wrote:

> Original poster: "Herwig Roscher by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <herwig.roscher-at-gmx.de>
>
> Barton B. Anderson wrote:
> > I'd say math was right and method was wrong
>
> Barton,
>
> So I had a partial success at least  ;-)
>
> > Have you ran your math with a typical transformer?
> - One of my larger MOTs takes 0.4 A without load at 230 V / 50
> Hz. In order not to confuse anybody, I scaled it to 120 V = doubled
> the current for the example (not really correct).
>
> > How about my pole pig:
> > Open load current of primary winding = 0.25 A
> - That's really small!
>
> > Hold on to your seat,
> > Add 50 % for LTR-cap: = 1.15 nF
> - Amazingly small and obviously wrong for a pole pig!
>
> > Cres should be near to 128nF.
> - Calculated or found from tests?
>
> > I'd say your better off sticking with Terry's formula of 0.83 x Io /
> (BPS x Vo).
> - A clear word - thank you!
>
> Take care,
>
> Herwig