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Steve,
I don't really know for sure if the little fins work #that# well, but
they must aid cooling a bit, however the main cooling comes from the
(1.5" diam') solid copper posts that have fining on them.
http://www.hvtesla.com/img/srsg-2015-2.jpg
There is of course a considerable draft created by the rotor itself, and
I even admit to trying a 'nerdish' test where I injected smoke into the
air path to see where it flowed and, on my coil at least, the posts
received a considerable cooling air stream.
Phillip S literally has zero ablation on his terminals, and I believe
this is down to the fact he uses pure Tungsten 'slugs', unlike welding
(GIT) electrodes where the majority have trace elements added. The
colour of the rod indicating the additive. (green is said to be 'pure')
. I use a Copper/Tungsten mix for my fixed electrodes, and TIG welding
electrodes (not pure) for the flying ones and I get bad ablation for the
same power as Philip S uses (in fact we share the same pig power supply
inc' ballast) most of the ablation being on the Copper/Tungsten mix
electrodes. But unlike Philip S my electrodes are a bit undersized for
the power used so that doesn't help matters.
Gapping can play a role as well I've found. I gap mine at 8 thou
initially and these can wear to 12/15 thou, the wear accelerating the
bigger the gap gets, also as the gap increases the phasing of the SRSG
alters slightly a bit as well, meaning a small adjustment on the Frau
phase controller. (I run 200bps where the sound of the coil - 2 firings
per 1/2 power supply cycle, makes it easy to discern a slightly
off-phase setting - something only 200bps allows) That's sounds a bit
barmy and obsessive I know, but my aim is always to squeeze every last
bit out.
Geez I've rattled on.............hope no-one is too many sucking eggs
reading any of this ..........good coiling to you from the UK
--
Regards Phil www.hvtesla.com
On 17/08/17 05:15, Steve White wrote:
In an attempt to reduce the erosion of my stationary RSG tungsten electrodes, I machined on my lathe a set of small heat sinks that mount 1/2" away from the spark gap firing point. They are similar to those shown on the "hvtesla.com" web site except mine are made from aluminum instead of copper. The problem is that the high temperature seems to be pitting the face of the heat sinks facing the spark gap. I note that aluminum melts at 1200 degrees F and copper melts at 1900 degrees F.
In an attempt to correct this pitting problem I have ordered a set of aluminum nitride sheets. Each is 1.5" x 1.5" x 1 mm. Aluminum nitride is a ceramic which melts at 4000 degrees F. My idea is to attach these small sheets to the face of the heat sink closest to the spark gap in order to prevent the pitting (melting) of the aluminum. I then wondered if attaching copper sheets to the aluminum would have done the job since copper's melting point is higher.
Does anyone using copper heat sinks on the stationary tungsten electrodes have a problem with the copper pitting (melting)?
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