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Re: Aluminum electrodes in TCBOR static gap
Hi all,
>> The gap unit WAS firing and making a huge glow, but no spark.
>
> This sounds very much like something that Malcolm mentioned about
> his single static gap running well at low voltages, but just "fizzing"
> at higher voltages. This sounds like a total power input power
> arc....no quenching at all. In other words, like just arcing a NST as
> in a Jacob's ladder more or less, possibly caused by overheating of the
> gap.
>
> cheers,
> John Freau
I think this behaviour may be due more to overheating of the static gap,
than lack of actual quenching. I have seen this happen whilst monitoring
the static gap voltage waveform. When the static gap overheats the
breakdown voltage drops considerably, and the spark gap seems to
"re-ignite" preamaturely following each firing. This results in the
static gap firing at a much faster rate, but with the tank capacitor only
partially charged. The higher firing rate causes a high pitched "frantic
fizzling" sound from the gap and even more heating.
Since bang energy is proportional to V^2, the lower firing voltage causes
bang energy to drop like a rock ! Although the firing rate is higher, it
is outweighed by the massive drop in bang energy. The total power
throughput falls and the secondary sparks cease.
I found that high voltages, and small capacitors were worst for provoking
this effect. I eliminated the problem with a large volume of air blown
through the TCBOR-gap, before moving to a rotary design.
Well that is my theory anyhow,
Comments ?
Cheers,
- Richie,