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Re: MMC Calculator Program





Tesla List wrote:
> 
> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
> 
> Hi All,
> 
>         I wrote up a little program that will do all those nasty MMC
calculations.


Thanks! It is a nice program, and I can verify its operation, to some
degree:

With my silly little coil, 4 strings with 2each caps is listed as too
hot! : they lasted about 10 minutes, of course just 2 caps also are
listed too hot, they last less than one minute.
I have not tried 6 strings with 3 caps in each, they would be high risk,
but 4 in series, and 8 strings is listed as safe, and they stay
completely cold.
I`m using Phillips 376 mmkp 56nF/1600VDC

MMC Calculator  Ver. 1.1  2/15/2000  Terry Fritz
 
Firing voltage =  5000 
Fo =  300000 
Break rate =  300 
Cap value =  5.6E-08 
 
Strings   Caps/String   Total Value   Temperature   Cost
  2         1           112.00       107.13          12.00  Too Hot!
  4         2           112.00        26.78          48.00  Too Hot!
  6         3           112.00        11.90         108.00  Some Risk
  8         4           112.00         6.70         192.00  Safe
 10         5           112.00         4.29         300.00  Very Safe


> It is sort of geared to my Panasonic caps but if you change the heat
> dissipation constant in line 1260, it should basically work for any.  It is
> based of the calculations at:


It would be nice, if the program could also ask the lead spacing, and
then itself substitute the corresponding dissipation.


> Most things are worst case but the numbers seem to work fine.  Hopefully
> this will make MMC design much easier especially for the critical
> temperature rise aspect.

It has, however I am, after runnung the numbers, still glad that I made
my 34nf cap for the museum coil, as rugged as I did: (This is with the
dissipation changed to 67, for the 22nF caps I used then)

MMC Calculator  Ver. 1.1  2/15/2000  Terry Fritz
 
Firing voltage =  25000 
Fo =  100000 
Break rate =  300 
Cap value =  2.2E-08 
 
Strings   Caps/String   Total Value   Temperature   Cost
  3         2            33.00       %1099.85          36.00  Too Hot!
  6         4            33.00       274.96         144.00  Too Hot!
  8         5            35.20       175.98         240.00  Too Hot!
  9         6            33.00       122.21         324.00  Too Hot!
 11         7            34.57        89.78         462.00  Too Hot!
 12         8            33.00        68.74         576.00  Too Hot!
 14         9            34.22        54.31         756.00  Too Hot!
 15        10            33.00        43.99         900.00  Too Hot!
 16        10            35.20        43.99         960.00  Too Hot!
 17        11            34.00        36.36        1122.00  Too Hot!
 18        12            33.00        30.55        1296.00  Too Hot!
 19        12            34.83        30.55        1368.00  Too Hot!
 20        13            33.85        26.03        1560.00  Too Hot!
 21        13            35.54        26.03        1638.00  Too Hot!
 21        14            33.00        22.45        1764.00  Too Hot!
 22        14            34.57        22.45        1848.00  Too Hot!
 23        15            33.73        19.55        2070.00  High Risk
 24        15            35.20        19.55        2160.00  High Risk
 24        16            33.00        17.19        2304.00  High Risk
 25        16            34.38        17.19        2400.00  High Risk
 25        17            32.35        15.22        2550.00  High Risk
 26        17            33.65        15.22        2652.00  High Risk
 27        17            34.94        15.22        2754.00  High Risk
 27        18            33.00        13.58        2916.00  Some Risk
 28        18            34.22        13.58        3024.00  Some Risk
 28        19            32.42        12.19        3192.00  Some Risk
 29        18            35.44        13.58        3132.00  Some Risk
 29        19            33.58        12.19        3306.00  Some Risk
 30        19            34.74        12.19        3420.00  Some Risk
 30        20            33.00        11.00        3600.00  Some Risk



> 
> Comment suggestions welcome.  I am no computer programmer but the basics of
> how the program works should be easy to see.
> 
> Cheers,
> 
>         Terry
> 

Thanks for another very usefull tool!

Cheers, Finn Hammer