Hi Bert,
I have never cooled this gap but will do so in the future. The capacitors
are new Cornell Dubilier 942c20p15K-F purchased from Online Components.
There are 19 caps in a single string per the MMC Design Chart for a 15/30
NST.
The bleed resistors I'm using are 10meg, 1/2 watt, but I don't know the
mfg. or part number as I get them from the electronics dept. here at work.
There have been no anomalies with the resistors during or after operation.
I will check into the resistors you sited.
Phil, thanks for the advice on the spark gap. I pulled the gap assembly
last night. The steel is rusted and the tungsten carbide faces need
cleaning.
Thanks guys,
Tim
On Thu, Mar 13, 2014 at 7:27 PM, Phil Tuck <pip@xxxxxxxxxxx> wrote:
> I know it was working originally on steel electrodes ok, but consider
> changing them one day anyway - steel heats up hot anyway with RF, but
> working in a spark gap as well, means double trouble :-)
>
> Phil
> www.hvtesla.com
>
>
>
>
> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
> Of Tim Flood
> Sent: 13 March 2014 20:48
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] Spark Output?
>
> Thanks guys for the suggestions so far.
>
> The electrodes are not copper but 3/8" dia. steel round bar with tungsten
> carbide silver solder on one end so four pairs of flat round flats face
> each
> other. These steel rounds are mounted in aluminum blocks and are
> adjustable.
> It could be over time corrosion has developed over time between the steel
> and aluminum. I will disassemble and inspect this weekend.
>
> The caps that make up the MMC are new. They checked out OK individually and
> as a unit. Is it probable that a number of these caps could break down
> under
> load?
>
> Thanks again and I'm open to any ideas.
>
> Tim Flood
>
>
> On Thu, Mar 13, 2014 at 3:22 PM, W5als <w5als@xxxxxxxxx> wrote:
>
> > Hi Tim
> > This my opinion but I think the cap's are breaking down under
> > load. I know they test Good but that doesn't mean they are. Just my
> > thoughts.
> > Alton
> >
> > Sent from my iPad
> >
> > > On Mar 13, 2014, at 1:54 PM, Tim Flood <tfloodrr@xxxxxxxxx> wrote:
> > >
> > > My old reliable coil's streamer length was gradually diminishing
> > > from
> > white
> > > long sparks to shorter purple sparks and finally purple sparks for
> > > about ten seconds then no sparks. Additionally, racing arcs were
> > > beginning to occur.
> > >
> > > The MMC value checked out, all connections checked out, I cleaned
> > > and re-connected the dedicated RF ground, etc.
> > >
> > > The old design utilized two paralleled 9/60 NST, 3" dia. sec. and a
> > 3"x12"
> > > toroid with a spark gap consisting of four fixed gaps in series.
> > >
> > > I suspected the transformers so I replaced these with the only other
> > > one
> > I
> > > had, a 15/30 NST. I ran the new transformer, required capacitance of
> > .008uf
> > > along with the existing secondary, spark gap and top load through
> JAVATC.
> > > Modifications were then made per the JAVA.
> > >
> > > The first light of the modified coil only produced a weak purple
> > > spark
> > with
> > > a break-out point. Tuning only served to create racing arcs, with no
> > > improvement in performance.
> > >
> > > Now I suspect the secondary. So, I rewound and varnished the secondary.
> > > Same dismal performance as before. Now I'm about ready to loose it,
> > > to
> > the
> > > point I'm explaining this all to my wife.
> > >
> > > The only thing I didn't touch was the spark gap and gap spacing. It
> > > was
> > set
> > > for .030" for each of the four gaps and I made no adjustment when I
> > > switched transformers.
> > >
> > > Sorry for the long post, but I would really appreciate any ideas.
> > >
> > > Thank you,
> > >
> > > Tim Flood
> > > _______________________________________________
> > > Tesla mailing list
> > > Tesla@xxxxxxxxxx
> > > http://www.pupman.com/mailman/listinfo/tesla
> > _______________________________________________
> > Tesla mailing list
> > Tesla@xxxxxxxxxx
> > http://www.pupman.com/mailman/listinfo/tesla
> >
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