Re: [TCML] Spark gap Resistance

["Chris Swinson" <list@xxxxxxxxxxxxxxxxxxxxxxxxx>]

Hi all,

I wonder, could the spark gap not be tested in some way...

Years ago I tried a silly small test of placing a 500W NST across a 50W lamp 
via a spark gap. It was some 15 years ago so do not recall exactly, though I 
remember that the lamp did not light at all even though the gap was arcing. 
I suppose the test was daft anyway but hopefully sparks some ideas!

I wonder if current could be tested using a lot of voltage dividers and 
maybe measure the current on a regular meter some how, maybe use larger and 
smaller tank caps..

Or maybe just wind a step down down. say 50 turns primary and 5 turns 
secondary to step down the voltage to a readable level and try different 
tank cap values and measure the current.

Or maybe just a high voltage sense resistor of very low ohmic value and read 
the voltage drop across it could be the easy solution. Might be easy for 
someone who has a scope who can connect it in such a way to do the testing ?

Would be interesting to see how much current goes across the gap. Would be 
also interesting to vary the gap spacing and repeat all tests again. Such as 
testing a few tank cap values 10,20,40,80,100nF at 1mm increasements across 
the spark gap

There is a lot of problems though... for example if 40nF cap used pulsed 
400amps and the 100nF could only pulse 50amps then it would make an unfair 
test. So as the cap size increased the cap itself would be limiting the 
current flow rather than the spark gap... It could also happen in reverse 
also, larger caps generally can pulse more current so may appear to make the 
spark gap conduct better the larger the cap value is.

So if the values of caps alters, then their own current rating should also 
be matched. It could take 100x 1nF caps to get to 500amps, or 1x 100nf cap 
may only be 100amps or could be 1,000amps!

Or maybe the spark gap current could be current limited to a set figure, 
then try spark gap spacing, and various tank cap sizes... then maybe half 
the current limit and repeat all tests again.

I think some of my points may get overlooked such as "the current of the 
caps does not really matter" kind of thing, but it maybe so, or maybe not, 
It would just be someone opinion which will "skip" over some vital test 
data. I think a lot of tests are needed to be done so solve all the 
questions.

Maybe it would work just using a very high current pulse 100nF cap and 
ballast to 10amp increasements.. and do the tests at 1mm increasements over 
the spark gap...

I assume 50/60hz over the gap during these tests. Frequency I think also 
should improve things though I think for now just the raw current tests and 
spark gap spacing are the most valuable aspects for the moment..

I personally think the wider the gaps are, with more current, and hgher 
frequency...the better the conduction will be.. Though I think I am on my 
own with that idea.

I think the issue needs to be tested and data/graphs drawn up to solve the 
issue once and for all... Cannot be that hard for some of you guys who have 
all the stuff to hand to setup and document ?

There would also be a "control test" where the test would be done with a 
link over the spark gap. Even linked vs spark gap is good info to have as 
right away you know what is lost over the gap in that one single test! Then 
increase the current pulses and work out if the gap conducts better or 
worse.. plus also spacing of the gap could well be important.. really a lot 
of tests but I think if all these tests are done and drawn up in a line 
graph we can see easily the differences vs the control (linked gap) 
figures.....


Chris


_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla