Re: Power vs. Spark Length

From: 	Peter Electric[SMTP:elekessy-at-macquarie.matra-dot-com.au]
Reply To: 	elekessy-at-macquarie.matra-dot-com.au
Sent: 	Saturday, July 26, 1997 7:39 AM
To: 	Tesla List
Subject: 	Re: Power vs. Spark Length

> I want to see what our coil's maximum spark capabilities are.  By
> measuring max spark length, you're right, I'll never know how much
> power is in a certain spark...and I'm willing to accept that (for now).
> I'm sure there are other mechanical or electrical systems which also
> strive for max rather than average performance, i.e. the average is
> ignored as unimportant, although I can't think of any at the moment.
> As you said, we are making many compromises in using
> spark length as a measurement.  Using
> a controlled spark length...we are making more compromises.  By
> using max spark length we are just swapping one compromise for
> another...but at least the max spark length measurement allows our
> coil to be working in its normal mode of operation, and allows for a
> convenient way of comparing one coil with another.  Greg's idea of
> looking for a certain number of spark hits per minute is a helpful
> refinement. We can of course chose to measure our TC "efficiency"
> (layman's usage) in "sections" (power supply, RF section, etc), and
> this is a good idea to do.  Is this all scientific?  No.  Is it practical?
>  Yes.
> Perhaps in the end, some of us will favor one method, or another for
> our TC measurements and analysis, and all these methods will over
> time gradually improve our understanding of these wonderful devices
> which we all enjoy even as we debate these issues.  In any case, it's
> time for buildin' and measurin'!
> Comments welcomed,
> John Freau

Being basically a practical type guy who enjoys the buildin' and
measurin' more than the theorizin', it seems to me that we have some
major problems measuring the performance of a TC without knowing the
peak voltage and current produced in a given spark. My 15KV 60Ma TC for
instance gives reasonable length sparks (no threat to the record
holders!) but my sparks are always fairly spindly and violet coloured.
On the other hand, I notice a lot of you guys with the bigger current
inputs seem to get sparks that are not that much longer, but much
brighter, white or blue sparks.

It seems to me that you need a certain voltage to break out of your
toroid but from then on current is more important. Possibly this would
explain the vastly different performance of different TC's running at
around the same input power levels. Some of them likely produce very
high voltages but lower currents while others produce lower voltages but
much greater currents. An added variable is the freq. of operation (at
least this is easily measurable). Maybe the best way to measure the
performance of a TC is to use absolute maximum spark length v brightness
(as measured by a photometer) v freq.

Has anyone actually attempted to directly measure the peak voltage in a

Trying to get the radius of the arc's longer in Aus...
Peter E.