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Re: LTR cap BPS?

Original poster: "Barton B. Anderson" <tesla111@xxxxxxxxxxxxx>

Hi All,

I'm still here, I've just been in lurk mode since March. I've been too busy with real work to do any coiling or spend much time with TCML. The last day I've had off at work was back in 2003.

The BPS stated at 60 must be a rather large cap size or small NST power. JavaTC does take into effect running at higher input voltages, but does not account for inductive kick. Javatc will also account for resonant rise if measured Rs and Rp are entered (there are inputs for measured NST values). The BPS can be above or below 120 depending on electrode size and gap width, cap size, and nst specs. It is about as good as can be done with calculation that I know of at this time, but of course, there are parameters within a gap setting which will effect your actual measured value. For example, heat!

Because Gary showed his bps values for the various cap sizes, maybe he could run through Javatc and see how it faired, but seeing that it is data from an old measurement, I know that gets difficult to do. Hard to do anyway.

For example, Gary's 4/20 NST run through Javatc (without actual measured Rs and Rp values) showed the following "assuming 2 electrode static gap at 1/4" electrode diameter" (of which I have no clue what it is). I also have no clue of the effects of Gary's partially shunted 4/20. That really throws things off. The only way I know about doing this is to input the NST and known cap size and change gap widths until BPS is relatively close and then wonder if gap width calc'd is near to the actual. From my vantage point, this is impossible to do with any accuracy. It's in the hands of the builder to measure and test and show error. This has really not happened as it should have with gaps. There are a few, but only a few (over many years).

Cap          Meas.     Calc.        Gap
Size          BPS        BPS   @  Width
----          ------      -----         ------
0.012uF   297         299           0.045"
0.02uF     207         210           0.025"
0.025uF   157         154           0.021"

It may be that the actual gap widths were all identical. But with the shunted and unmeasured Rs Rp values, who knows how it would really play out.

Although Javatc is fantastic with primary and secondary specs, I am not as confident on the remaining power, rsg, or static gap sections of the program. Comparisons of measurements and calcs are still needed in these remaining parts of the program to get that warm and fuzzy feeling.

Take care all.

Bart B. (in desperate need of a coiling vacation!)

Tesla list wrote:

Original poster: FutureT@xxxxxxx
In a message dated 11/30/04 9:07:31 PM Eastern Standard Time, tesla@xxxxxxxxxx writes:


Well, my question comes from
http://www.classictesla.com/java/javatc.html
Seems like if I use its LTR suggestion, it states 60~ or so BPS at any
decently wide gap setting for the NST.
Is this just the program screwing up and stateing 1/2 the BPS? or is it
really 60bps at those gap settings?




Bart's JavaTC is very good, but I don't think I exactly agree with
his method of figuring the BPS, etc.  I don't think JavaTC accounts
for the extra power that can be drawn out an NST beyond its
name-plate rating due to resonant or inductive kick and
input overvolting.  This extra power permits the breakrate to
be higher than expected using a given cap value.  Perhaps
Bart has updated his program, I don't know.  A too-wide
gap will tend to reduce the breakrate of course.  I do agree
with Gary Lau's previous comments regarding the breakrate.

John