Thank you Gary. I may want to experiment with the .015uF STR vs. the .03
LTR to see how each plays out. If I did that, do you think the .015 STR be
a safe value that would avoid capacitive resonance with the 15/135? Dennis
On Fri, Dec 22, 2017 at 6:57 PM, Gary Lau <glau1024@xxxxxxxxx> wrote:
> For the longest sparks, a Larger Than Resonant cap is recommended. The MMC
> design chart recommends for a 15/120 60 Hz NST w/ static gap, a .03uF cap,
> so for 15/135, you could even go a bit higher. Now LTR isn't the law, and
> one may in fact deliberately choose a STR cap, as it will have a different
> character of spark - shorter but brighter and more dynamic.
>
> Regards, Gary Lau
> MA, USA
>
> On Fri, Dec 22, 2017 at 3:56 PM, dennis otmaskin <dotmaskin@xxxxxxxxx>
> wrote:
>
> > Thanks Ian for your reply! What you say is encouraging to hear. If you
> > don't mind, I have one more question...
> >
> > Java TC indicates, for my 15/135 NST, that Resonant Cap Size would be
> > 0.0239uF. I understand that bad things happen when using resonant cap
> > size. So I'm trying to decide on whether to use a 0.03uF cap or a
> .015uF.
> > I've got one of each. The .03 cap is pretty close to the indicated .0358
> > LTR Cap Size for a static gap. On the other hand if I plug the .015 cap
> > into Java TC, it shows a dramatically greater rate of Breaks Per Second
> and
> > possibly a few more inches of spark length. My question is is there any
> > potential problem with resonant rise with the .015 cap. I.e., is the
> .015
> > cap value far enough from the resonant cap size to be safe?
> >
> > Thanks again for your help, Dennis
> >
> > On Thu, Dec 21, 2017 at 11:55 PM, Ian McLean <austesla@xxxxxxxxxxxxxx>
> > wrote:
> >
> > > Hi Dennis,
> > >
> > > If you have proper RCD¹s installed, it is unlikely you will trip a 15A
> > > circuit with 18A at least for the sort of runs lengths you do on a
> Tesla
> > > coil.
> > >
> > > I regularly ruin my tube coil at between 30A-40A from a wall socket.
> The
> > > RCD is only 20A, but it has never tripped even with a 2 minute run.
> > >
> > > Cheers,
> > > Ian
> > >
> > > On 22/12/17, 2:40 pm, "Tesla on behalf of dennis otmaskin"
> > > <tesla-bounces@xxxxxxxxxx on behalf of dotmaskin@xxxxxxxxx> wrote:
> > >
> > > >Hi I'm hoping someone from the list can offer advice some advice and
> > > >suggestions. I am replacing the 15/60 NST on my current static gap
> coil
> > > >with a de-potted NST with some shunts removed so that it puts out
> > 15000v @
> > > >135mA.
> > > >
> > > >Running different designs on Javascript Coil Designer, I'm finding
> that
> > > >the
> > > >Effective Input Current (current draw?) runs over 18 rms amps. My wall
> > > >outlets in the garage are all 15 amp. So if I'm understanding this
> > > >correctly, it looks like I would be constantly tripping the circuit
> > > >breaker
> > > >when running the coil at full variac voltage. I've run different cap
> > > >sizes
> > > >through Java TC but cant seem to get around the 18 amp draw.
> > > >
> > > >To get the current draw to just below 15 amps, I would have to dial
> the
> > > >variac down to 106 volts which would reduce the spark length
> > > >substantially. I'm thinking that I am pretty much stuck with a
> systems
> > > >that is limited to 106 volt input. Do you think this is the case?
> I'm
> > > >hoping that I don't have to rewire my garage outlets for 20 amps just
> > for
> > > >my coil. Any suggestions would be most appreciated.
> > > >
> > > >Thanks, Dennis
> > > >_______________________________________________
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