Re: Spark Gap Losses And Thoughts...and more Thoughts...


What a great topic!

It has always interested me in the dozens of gap designs from the old 
medical machines.

The early English style Tesla Coils used an annoying method of mica 
washers/copper discs as series stationary gaps.

The english style machines that did use regular adjustable gaps often had 
them enclosed in a container, with coal gas or spirits replacing the air in 
the gap.  I've never tried this, but literally dozens of [European] styles 
of machines used this method.  Wasn't the greatest method, but perhaps could 
be improved upon...

1920s machines often used series gaps, finned heatsinks.  This works well, 
but I've noticed that the machines with the larger surface area gaps (large 
tungsten surface) work better than similar machines with smaller gap surface 
area (even if more gaps were in series).

One thing that nobody does anymore (WHY?) is to make Tesla Coils with 
electromagnetic interrupters.  I know they aren't good for high power 
levels, but what is your opinion on them?  I know 6" sparks are possible 
with a good electromagnetic interrupter, the Betz machine on my site only 
draws an amp and throws one heck of a 6" spark.
Barely any arcing at the contacts, I don't see too much room for losses, I 
mean I'm impressed by that sort of spark-length to current drawn ratio!

Even drawing a couple of amps, (max. maybe 4-5 amps for a mechanical 
interrupter) most small neon transformers only draw 4-5 amps.

Tesla used mercury breaks - which I am not suggesting by any means everyone 
builds, but their related cousin from induction coils might work well -

electrolytic interrupters.  Why not??  I mean, they can handle TONS of 
current.  Wehnelt interrupters and Simon/Caldwell interrupters, you can 
easily drain 10 or 15 amps through them at 100 volts.
Why couldn't you use an electrolytic interrupter with a self-induction coil 
or induction coil to get high frequency pulses of high current, high voltage 
to operate a Tesla Coil??

With that said, Tesla Coils don't have to be the norm either.
That Betz coil has a flat spiral of wire embedded in wax, 9" diameter, 2" 
high.  And it throws a 6" spark...
The Violet Rays make little 1" sparks, painless, and their disruptive 
discharge coils are nothing like the Tesla Coils we see today.

I'm not suggesting we totally reinvent the wheel here, but in the first 30 
years of this century there were so many machines of fascinating design, and 
everyone ignores them. Spark Gaps and Coil winding techniques were the main 
selling points.
90 % of every Tesla Coil from the past 20 years looks the same.

In the first 20 years of this century there were names like Thomson, Dean, 
Fischer, Betz, Guilleminot, Oudin, d'Arsonval, Strong, Kinraide, Ovington, 
Rochefort, Schall, and countless others for their creative design in [if not 
anything else] commercial high frequency spark coils, yielding Tesla 

Frank Betz didn't decide to make Tesla Coils just like Kinraide.  He worked 
on Kinraide's idea and improved on it.
Too many of us coilers see some impressive masterpiece like a TTR coil and 
decide to build our own versions, though instead of improving upon it, we 
make the same idea but take short cuts along the way, and wonder why our's 
doesn't work as well!

I am currently attempting to scan pictures of the above mentioned spark 
gaps...I think everyone will find them interesting!

Electrotherapy Museum

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