Re: [TCML] tesla coil blowers

[David Petzer <davepetzer@xxxxxxxxx>]

The relationship between air pressure, electrode gap spacing and breakdown voltage is well documented by Paschen's law/curve.
 
The breakdown voltage does reduce with pressure to a point but then increases again when the pressure is further reduced. These low pressures are probably much lower than a normal blower could achieve (Wikipedia cites an example of 10^-3 atmospheres). 
 
The probability of a random free ion being pressent to start the breakdown is increased by the quantity of air flowing through the spark gap which would also lend it's self to lower breakdown voltage. 
 
- David


________________________________
From: Carl Noggle <cn@xxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx> 
Sent: Saturday, 26 November 2011 4:06 PM
Subject: Re: [TCML] tesla coil blowers

Hey---Sounds like a reasonable theory.  There should be a gap length for 
max performance corresponding to each blower speed.  I'll check it on 
mine--it's an annular blower gap.  I'll report findings.

---Carl




> Though no one asked, I'll offer my theory.  The air between the electrodes
> in a sucker gap is at a lower pressure than the surrounding atmospheric
> air.  As the pressure is reduced, the breakdown voltage of the gap is
> reduced.  A lower breakdown voltage delivers smaller bangs, and lower
> performance.  Just a theory though - I haven't run my sucker gap in many
> years and I haven't personally witnessed this.
>
> Regards, Gary Lau
> MA, USA
>
> On Fri, Nov 25, 2011 at 6:29 PM, Jonathan Peakall<jpeakall@xxxxxxxxxxxx>wrote:
>
>> I found with my sucker gap that too much vac actually decreased
>> performance. There was a sweet spot somewhere around the 20-30% power mark,
>> as Gary describes.
>>
>> Jonathan
>>
>> ----- Original Message ----- From: "Carl Noggle"<cn@xxxxx>
>> To: "Tesla Coil Mailing List"<tesla@xxxxxxxxxx>
>> Sent: Friday, November 25, 2011 8:04 AM
>> Subject: Re: [TCML] tesla coil blowers
>>
>>
>>  Thanks, Gary--after 20 years of running my coil I never thought of
>>> that.  Probably make for longer motor life, too, although in that time I
>>> have only had to replace it once.  Still, I had egg on my face in the
>>> middle of a show.  A small step-down autotransformer would work well, too.
>>>
>>> ---Carl
>>>
>>>
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