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

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

Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>

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