Re: [TCML] Still stuck at 36"

[DC Cox <resonance@xxxxxxxxxxxx>]

I usually run my hyperbaric gaps at 180 mills (0.180").  As they burn away
they do require some periodic adjustment, perhaps more so than the
parallel copper tube type gaps.

I've tried both sucking and blowing configurations on a variety of small and
medium size coils, and the blowing confirguration seems to be
the winner in most all of my coil setups.

I would encourage all List members to pick up a vac. cleaner motor/blower,
and experiment with these to replace current parallel copper tube
sparkgaps.  You will be pleased with the performance increase.  Again, at
most larger vac. cleaner repair shops, if you use the ploy "helping a kid
with a science project", they will usually give you one free, or, at most,
$10.

Better yet, enlist some local Boyscouts to engage in a small coiling project
and you will all have a lot of fun.  The Scouts light up like candles the
first time they actually see a coil run.  Then, of course, they all want to
build one and that's where the real fun comes in --- very enjoyable for both
you and the Scouts. I have a group of approx 8 Scout troops that come by the
shop and work for 3-4 hours every two weeks.  So far, the kids have built
over 65 Tesla coils which appear in science projects at local schools all
over Wisconsin.

I prefer to use the larger 2 1/2 inch PVC T fitting for my HB gaps.  The
smaller ones like 1" will sometimes melt from the heat.

My experience is they add 4" to 6" (or more) increased spark output to most
coil setups.  With the larger medium coils running 3-4.5 kVA I sometimes run
two in series to handle the higher currents.

If anyone is new to the list, I have both the plans for the hyperbaric (HB)
sparkgap and also plans for a nice small "starter" type coil which I
distribute free to anyone who contacts me off list with their request.  It
uses either a 9 kV or 12 kV, 30 mA, NST and MMC type capacitors.  Sec. is 4
x 24" size.  To keep costs down, we usually use an 8" copper plumbing float
(smooth) type for the upper terminal.

Dr. Resonance












On Sun, Jan 25, 2009 at 12:08 PM, bartb <bartb@xxxxxxxxxxxxxxxx> wrote:

> Hi John,
>
> futuret@xxxxxxx wrote:
>
>> By using a pressurized air gap, this should help reduce gap
>> losses since pressurized air breaks down at a narrower gap setting
>> than lower pressure air.  Also pressurized air should quench better
>> than lower pressure air.<snip>
>>
> What you say is correct. For a given voltage, the pressurized gap would
> need to have the electrodes closer together in order to breakdown at the
> "same" voltage level of a non-pressurized gap. If the gap is set properly
> under pressure with only the transformer prior to placing in the coil, then
> theoretically the electrode spacing should be tighter than the same gap
> without pressure. I wonder if anyone has checked the spacing of a
> pressurized gap against the same gap without pressure (but with air flowing)
> and what the change in spacing was? Just curious on how much of change in
> pressure was realized.
>
> Quenching and reduction of thermal losses would be the reason the gap would
> perform well, but I also wonder about the gap setting. If set too wide (for
> example set when not pressurized), then at pressure, the breakdown voltage
> would be higher and this would certainly force a higher energy bang
> (identical to increasing spacing on a non-pressurized gap).
>
>
> Take care,
> Bart
>
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>
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