[TCML] tesla coil blowers

[Ben Hatton]

On 11/26/2011 2:13 PM, Carl Noggle wrote:
> You're right.  The pressure at the Paschen minimum is what is in a 
> thyratron, OMs lower than atmospheric.
>
> ---Carl
>
>
>
>> 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 at q.com>
>> To: Tesla Coil Mailing List<tesla at pupman.com>
>> 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 at madlabs.info>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 at q.com>
>>>> To: "Tesla Coil Mailing List"<tesla at pupman.com>
>>>> 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
>>>>>
>>>>>
>>> _______________________________________________
>>> Tesla mailing list
>>> Tesla at pupman.com
>>> http://www.pupman.com/mailman/listinfo/tesla
>> _______________________________________________
>> Tesla mailing list
>> Tesla at pupman.com
>> http://www.pupman.com/mailman/listinfo/tesla
>> _______________________________________________
>> Tesla mailing list
>> Tesla at pupman.com
>> http://www.pupman.com/mailman/listinfo/tesla
>
> _______________________________________________
> Tesla mailing list
> Tesla at pupman.com
> http://www.pupman.com/mailman/listinfo/tesla
In a nutshell it blows out the ionized air making the gap more reliable 
and accurate.  I use a squirrelcage fan on a 1/2 hp big old motor.  
Never heard the pressure thing, true the pressure changes slightly with 
the movement of the air, (think airfoil)  but I say that if they make 
the gap better its because the moving air does not allow the gap space 
to be heated.  Think (jacob's ladder)