Re: V11.1 for JAVATC (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Wed, 29 Aug 2007 18:09:02 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: V11.1 for JAVATC (fwd)

Hi Tony,

Yes, LTR for an SRSG is typically about 2.8 x Cres which is about .059uF 
in your case. Javatc showed 0.0553uF.
The exact equation Javatc uses when looking at SRSG_LTR is: 
0.83*Iout/(2*Hz)/Vout.

Keep in mind this is based on 120 bps operation. If you were to run a 
bps higher or lower, the LTR value would be different. In the equation 
above, the (2*Hz) is actually bps. So, if you wanted to run at 240 bps, 
just use 240 in the equation above. Or you can let Javatc calc it for 
you by inserting a value of 120 into the Hertz input box and click the 
CALC button (this is kind of explained in the help link for srsg ltr 
output). Javatc would tell you that the LTR value would then be .0277uF. 
If you then used a .0277uF as your cap (in the primary area), be sure to 
return the transformer hertz value back to 60 Hz so that all the other 
calc's are meaningful. It's just a quick way to get LTR values for any 
bps value.

LTR for static gaps is about 1.5 x Cres.

If your ever curious as to the value shown with Javatc, you should 
reference:
http://www.classictesla.com/download/mmc_cap_chart.pdf

The above document was put together by Terry Fritz and shows Static and 
SRSG LTR values for various NST sizes at 120 bps. It also gives the 
number of strings to connect in parallel and the number of caps per 
string to use for the 942C20P15K (0.15uF, 2kV) caps. Note, for a 15/120 
NST at 60 Hz, Terry shows .0553uF (identical to Javatc). Now you know 
the equation. These "cap values" were based on testing by Terry and 
others (a lot of work on their part).

They are conservative values, so you do have flexibility. They are 
simply recommendations for NST protection.

Take care,
Bart

Tesla list wrote:

>---------- Forwarded message ----------
>Date: Tue, 28 Aug 2007 07:23:48 -0700
>From: Anthony R. Mollner <penny831@xxxxxxxxxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: RE: V11.1 for JAVATC (fwd)
>
>I like this program, it's a real time saver. I was surprised at the
>capacitor value it figured for my set up. I'm running a 15/120 input with a
>SRSG and the value that JAVATC gave me of .055 for LTR. This was a lot
>higher than I would have imagined, does that sound right?
>
>Tony
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