[TCML] Arc Temperature

[David Rieben]

Hi Clive,

As Jim Lux has already mentioned, the core of the arc is on the
order of 7000K, but at the relatively low power of the 15/30
NST, the actual plasma "channel" is probably less than 1 mm
in diameter and therefore has too little surface area at that tem-
perature to overcome the thermal mass of your nail to get the
nail hot enough to melt - i.e. the nail is conducting heat away 
faster than the tiny arc channel can heat it up. With your MOT,
the arc channel is considerably thicker (though still quite small)
due to the greater available power and is able to heat the nail 
to the point of melting. OTOH, if you were using a 1" thick
steel rod to draw the arc off of, the MOT's power level would
never be able to melt the end of that rod because of the much
greater thermal mass of the steel rod vs. that of the nail. That's
why a small 120 volt arc wleder can't weld metal that's over 
about 3/16" thick whereas a huge industrial 480 volt, 3-phase arc 
welder can easy weld 1/2" thick steel plate. The yellow/orange 
"flame" that you are seeing is not that central plasma channel but 
are air gases in the immediate proximity of that arc channel that are
partially ionizing due to their proximity to the hot plasma.

David Rieben


----- Original Message ----- 
From: "Clive Hansen" <mrclivehansen at gmail.com>
To: "Tesla Coil Mailing List" <tesla at pupman.com>
Sent: Monday, December 03, 2007 11:10 PM
Subject: Re: [TCML] Arc Temperature


> The arc is completely yellow/orange at about 1 inch in length. I just 
> need a rough estimate of the temperature. It is not hot enough to melt 
> the steel nails it is arcing to even after 30 minutes of operation 
> compared to my mot which will melt nails in less than 1 minute.
> 
> -Clive
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