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Re: Discharge impedance of a CW Tesla coil

Hi Reinhard,

At 03:33 PM 03/12/2000 +0100, you wrote:
>Hi Terry,
>
>> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>> I have been playing with my patched together RF generator and
>>measurement equipment.  Today I took off work early to do
>> something important. ;-))  I was able to measure the impedance
>>of the brush discharge of my coil run from the generator in CW
>>(continuous wave) mode.
>
>Snip.
>
>A very interesting experiment. Now what would be of even
>more interest to me, is what kind of primary capacitance did
>you use? MMC? EMMC? How was it built and what difference
>did you notice in cap performance (vs. a normal DW coil). Did
>they run hotter, etc, etc? I am sure all the toob-groovies or
>those solid state junkies out there would appreciate feedback
>on (E)MMC design for a CW coil ;o)).

It doesn't have a primary capacitor...  That wasn't the answer you expected
was it? ;-)))

Tube coils use a LC tank circuit to create the powerful sine wave that
drives the primary coil.  The primary coil, primary cap, and tube all form
the power supply.  In my case, I just turn the generator on ;-))  It drives
the primary coil with just the same type sine wave but no other components
are needed.  The RF generator does all that.

>
>I am not sure why you noticed less ozone, but the reduced
>NOx is probably due to the lack of the spark gap. I donīt
>think the coilīs discharge produces noticeable amounts of NOx,
>but the pulsed power you see in a DW powered coil, in the
>main spark, is (I think) the main source of NOx and not the
>coilīs output itself. Due to the outer shell state (electron
>configuration) of nitrogen, it takes a lot of energy to get
>nitrogen to combine with oxygen to form NOx. Nitrogen is a
>very stable element, whereas oxygen can easily be "tickled"
>into combining with another element.

Interesting thought about no spark gap.  Others with tube coils get ozone
however.  Last night I ran in a closed room and I could not smell anything
odd.  There was a "barely" perceptible electrical smell (maybe very low
level ozone) but I really could not smell anything.  For some reason, my
coil definitely appears to be producing hardly any ozone. 

>
>Taking a wild guess on ozone: The area of the CW discharge
>is much smaller than that of a similar DW powered coil, so you
>may be effectively re-combining less O2 molecules to O3
>radicals (they come in contact with less oxygen from the air,
>because the discharge is shorter). You may want to try using
>a small (very low cfm) fan during a CW run. If the amount of
>ozone increases (you would then be replacing reduced arc
>surface area for an increase in cfm => increased ozone supply),
>this is most likely the reason. Also, as you need energy to split
>an O2 molecule into separate O atoms, the DW coil might be
>able to do a *better* job, because the peak energy is much
>higher than that of a CW coil.

We will definitely have to find the reason for these differing amounts of
ozone between coils.  Perhaps if we can understand the mechanism behind
this, we can find new ways to reduce ozone on other coils...

Cheers,

	Terry

>
>Coiler greets from Germany,
>Reinhard
>
>
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