Re: Spark length equation and pri. program

["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 6/27/01 7:21:14 PM Eastern Daylight Time, tesla-at-pupman-dot-com 
writes:

> >
>  > I have been thinking lately about the relationship between spark length 
> and 
>  > voltage. current isn't a factor is it? for example, 12kV can jump about 
>  > half and inch, and 1MV can jump, (guessing here) two yards? I was trying 
> to 
>  > figure out an equation to find max. spark distance by voltage, but 
haven't 
> 
>  > been able to do so. Someone had to already find it, and I'm probably 
just 
>  > re-inventing something, but hey, its worth a shot... 
>  
>  
>  Jonathon, 

Jonathon,

Current is very important to Tesla coil spark lengths as
well as voltage.  Once the spark breaks out, current is 
needed to extend the spark.
Assuming normal Tesla voltages, and suitable coil design,
the spark length depends mostly on the power input which
includes both voltage and current.  I use the equation:

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

>From the equation it can be seen that
an efficient coil will give about a 42" spark from 600 watts
or so.  A less efficient coil may give only half that spark
length from that power input.

John