Re: Calculation of tank cap

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

Original poster: "Herwig Roscher by way of Terry Fritz <twftesla-at-qwest-dot-net>" <herwig.roscher-at-gmx.de>


Terry Fritz wrote:
> The 0.83 is from computer modeling and seems to be very 
consistent for various current limited transformers.

Terry,

Thank you for the explanation.

Sorry to bother you again: Is this formula valid for *all* kinds of 
xformers as well (you wrote "for various current limited 
transformers")?

I am obstinate: What do you think of another approach:

1. Measure the open load current of the transformer's primary 
winding (with inductive ballast connected) e.g. 0.8 A

2. Calculate the magnetizing inductance e.g. Zprim = 120 V / 0.8 A 
= 150 Ohm and Lmag = 150 / (2 x 60 x pi) = 0.4 H

3. Measure the transformer's voltage ratio e.g. 120 V / 2000 V = 
0.06

4. Calculate the reflected inductance e.g. Lref = 0.4 / 0.06 ^2 = 111 H

5. Calculate the size of the reso-cap e.g. Cres = 1 / [(2 x pi x f)^2 x
Lref] = 63.4 nF 

6.Add 50 % in order to get the capacitance of the LTR-cap e.g. 95 
nF (seems to be a bit large ;-)  Wrong methode/values?)

Your critics are very welcome!

Hoping for your understanding,

Herwig