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Re: Questions from a new coiler (all conceivable questions?)



Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <stanmoore-at-mindspring-dot-com>

Bill,

I am also building Terry's NST protection circuit.  For what its worth:  I
am using 1/2" balls from an old ball bearing for my gap.  I had a friend
weld a 1/4-20 bolt to each of the three balls.  The bolts will allow for the
gap adjustment.

Stan

>Hi Bill,
>
>At 10:31 AM 1/2/2001 -0500, you wrote:
>snip...
>>
>>I'll be building an NST protection circuit, following Terry Fritz's
>>plans.  Any suggestion for how to build the safety spark gap?  Does
>>anybody know where to get tapped brass balls?  (I found one place that
>>only sells large quantities)
>
>I used acorn nuts.  The hardware store had them in brass.
>
>>
>>
>>I'm planning on using a larger-than-resonant cap (2nF ?) to further
>>protect my NST's, an MMC with the Panasonic caps Terry is
>>buying/selling.  I still haven't decided on the string length.  I'd like
>>to build this once and not have to be repairing it.
>
>I think you want 25nF.  Add the 15/60 and 15/30 from the chart I just
posted.
>
>My program at:
>http://hot-streamer-dot-com/TeslaCoils/programs/Mmccalc2.zip
>
>Gives:
>============================================
>MMC Calculator  Ver. 2.2   9/12/2000  Terry Fritz
>Transformer voltage =  15000
>Transformer current =  .09
>Firing voltage =  21213.15
>Fo =  250000
>Break rate =  120
>Thermal dissipation constant =  40
>Individual cap value =  5.6E-08
>
>Strings  Caps/Str  Capacitance  Voltage   Temp C    Cost              I
Arms
>  3        7         24.00        11200    15.74   37.80  :-((  :-(   11.7
>  4        9         24.89        14400     9.52   64.80  :-((  :-)   12.14
>  5       11         25.45        17600     6.37   99.00  :-|   :-)   12.41
>  6       13         25.85        20800     4.56  140.40  :-|   :-))  12.6
>  6       14         24.00        22400     3.94  151.20  :-))  :-))  11.7
>--------------------------------------------------------------------
>  7       15         26.13        24000     3.43  189.00  :-))  :-))  12.74
>  7       16         24.50        25600     3.01  201.60  :-))  :-))  11.95
>  8       18         24.89        28800     2.38  259.20  :-))  :-))  12.14
>  9       20         25.20        32000     1.93  324.00  :-))  :-))  12.29
>===============================================
>
>So 6x14 would do fine.  Each string would be 4nF so you could hit 12, 24,
>and 10nF (two stings in series).
>
>Cheers,
>
> Terry
>
>