Re: Simple question

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 8/17/01 11:12:41 AM Eastern Daylight Time, 
tesla-at-pupman-dot-com writes:

> I have asked this a couple of times but havent really
>  heard anything that helps,
>  I have a power source, but to make it work I have to multiply
>  and rectify the voltage giving me DC. Does the firing rate
>  of the spark gap give me anything I can use to design 
>  the rest of the coil. I asked for some equations but 
>  no one seems to have any. This list has been a great help.
>  
>  Thanks,
>  Darin

Darin,

The firing rate or breakrate has significance for coil design
for two reasons.  First, a higher breakrate is generally less
"efficient" for producing long sparks with a given input power.
Second, a higher breakrate permits the use of a smaller
secondary and toroid for a given spark length, because the
bang size is smaller.  Regarding formulas, I found that
using larger bang sizes is twice as efficient as using higher
breakrates for obtaining long sparks.  Also, the secondary
length should scale up by the square root,
for a given breakrate.  For instance if the input power is
doubled for a given breakrate, then the secondary should be
made 1.41 times as long to prevent coil breakdown.  These
are general rules, but you can use them to create helpful
formulas for your coil designing.

  spark length (inches) = 1.7*sqrt power (input watts)

may help too.  Figure that for a 59" spark, the secondary
needs to be about 24" long at 120 bps to prevent coil
breakdown.

John Freau