RE: [TCML] Spark gap

["Jim Mora" <jmora@xxxxxxxxxxx>]

>From the archives and Richard Quick...

"This gap offers several advantages over many of the gaps I have
studied. It frees the coil up from any electrical utility
required when fans or blowers are used on a static gap. This is
also true when a rotary gap system has been used with a neon
transformer power supply, as this gap can replace a rotary in
this application and give better performance. This gap has very
high Q and gives extremely low quench times. The performance of
this gap on coils powered by neon sign transformers is second to
none. If you run neons, and you want the longest spark at any
cost, then this is the gap for you.

The system consists of two electrodes cut from 1 inch brass bar
stock. The electrodes are 1-1/2 inches long by 1 inch diameter.
The back side is machined one inch deep to accept a 3/8 inch
threaded brass dowel. The face of the electrodes are flat and
polished. The electrodes weigh 4 & 3/4 ounces each and sink a lot
of heat without requiring cooling fins. Beneath the gap, I
mounted a 1/2" ID pipe fitted with a standard male air coupling
at one end. I hook the air feed pipe to a two-stage piston air
compressor, and using a regulator, blow 20 psi (minimum) of air
through the gap electrodes from the bottom up. It quenches
extremely well.

With the arc shielded during operation, the compressed air blows
a clearly visible jet of hot ions upwards from between the gap.
The flame extends one to two inches high. Even after 15 minutes
of operation at 2 kw, the electrodes are barely warm to the
touch.

This configuration offers several advantages:

(1) Gap distance can be adjusted precisely and quickly by
rotating the electrodes on the threaded rod, as opposed to most
multiple and quench gaps. (2) Higher power can be accommodated
simply by increasing the air feed pressure (or CFM). (3) A single
pair of strong magnets can be mounted on either side of the brass
gap to assist quenching at even higher powers by dispersing ions
away from the arc and into the high speed airstream. (4) The
electrodes can be quickly removed for examination and/or cleaning
without disassembly of the gap. My electrodes require a light
burnishing with #1200 sandpaper after every hour of operation.
The procedure takes less than 5 minutes..."


-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of penny831@xxxxxxxxxxxxx
Sent: Friday, February 22, 2008 9:25 PM
To: Tesla Coil Mailing List
Subject: [TCML] Spark gap

I'd like to build one of these hyperbaric spark gaps. Does anyone have any
good construction information on them?
Tony
ae6do

-----Original Message-----
>From: resonance@xxxxxxxxxxxx
>Sent: Feb 22, 2008 8:33 PM
>To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>Subject: RE: [TCML] Spark gap
>
>
>
>
>This certainly makes sense when one considers the immense energy lost in
>heating each separate multiple gap, and also the UV and light energy
>losses.  Heat is the worst though, and by using less gaps with a nice
>500-700 CFM of airflow quenching is usually efficient with low loss of
>thermal energy in a well designed two electrode gap vs. say a 5-6
>electrode gap.
>
>Dr. Resonance
>
>
>
>> It was after reading a paper published by Terry Fritz that I first came
to
>> the opinion that multi-segment gaps have higher losses despite offering
>> better quenching.  See
>> http://www.hot-streamer.com/TeslaCoils/MyPapers/sgap/sgap.html.  Perhaps
>> I'm reading it wrong, but it looks to me like the peak secondary voltage
>> is significantly higher in the single-gap cases when the coupling is in
>> the region where we typically use it.  And independent to that, I'm
pretty
>> sure that I've read that spark gaps are similar to zener diodes, in that
>> they exhibit a near-fixed on-voltage independent of gap width.  (This is
>> where Bert Hickman usually chimes in...)
>>
>> There is no doubt that multi-gaps exhibit superior quenching over
>> single-gaps, but contrary to what is often repeated on this list,
>> quenching is not the primary determinant of gap performance.
>>
>> Regards, Gary Lau
>> MA, USA
>>
>>> -----Original Message-----
>>> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
>>> Behalf Of bartb
>>> Sent: Friday, February 22, 2008 9:31 PM
>>> To: Tesla Coil Mailing List
>>> Subject: Re: [TCML] Spark gap
>>>
>>> Hi Gary,
>>>
>>> I'm undecided on the single segment versus multi-segment gap losses. The
>>> only possibility of lower losses is "if" the arc resistance is lower in
>>> a single segment gap. The voltage drop should be the same for both
>>> assuming identical pipes diameters, surface, and total gap spacing.
>>>
>>> Take care,
>>> Bart
>>>
>>>
>>> Lau, Gary wrote:
>>> > I'm similarly skeptical about a propeller gap's quenching.  The only
>>> thing that I
>>> can see superior quenching-wise is that the air flow over the gap may be
>>> better
>>> than in a cylinder gap.  But if that was all you need for superior
>>> quenching, then an
>>> air-blast gap should be the best solution of all.
>>> >
>>> > I would think that a mult-segment cylinder gap is the best at actual
>>> quenching,
>>> due to the fact that being divided into multiple small arcs, they would
>>> be easier to
>>> cool and extinguish.  But I also believe that multi-segment gaps exhibit
>>> higher
>>> losses (each gap represents a fixed voltage drop, and the more gaps in
>>> series, the
>>> greater the total gap voltage drop, and loss).
>>> >
>>> > The benefit of a propeller gap comes about in that it's a rotary gap.
>>> If it's a sync
>>> gap, it's superior because the bangs can be engineered to be consistent
>>> in size and
>>> timing, rather than the chaotic mode inherent in static gaps.  If it's
>>> an async gap, it
>>> may be better than a static gap if the power supply is larger than what
>>> can be
>>> effectively handled with a static gap.
>>> >
>>> > Regards, Gary Lau
>>> > MA, USA
>> _______________________________________________
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>
>
>Dr. Resonance
>
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