Hey y'all I keep seeing this thread bouncing from person to person and so
I'm just coming in. Originally I wanted to buy the transformer that was for
sale here but couldn't make it there to pick it up. I built a NST coil that
has a 4-in secondary and was having trouble with it having racing sparks.
After changing many things I discovered that it had too many windings. It
was way too long for it's with and so I pulled 450 windings away and that
got me closer to finding resonance with the secondary.. I have two neon
sign transformers, One of them is 10,5 00 volts with 30 milliamps and the
other is 15,000 volts with 30 milliamps and I had to remove the ground
fault on the smaller one so it would continue to work but it's still just
doesn't have the power to satisfy even close to what Tesla TC says it
should do. I was lucky and found four capacitors that are mica silver made
by custom electronics. Rated for 0.0153 microfarad each and 30000 volts so
I don't think the capacitors are the problem ..I needed .008 microfarad and
it just so happens that two of them in series gave exactly that number!
This coil was initially started on the idea that I would make one out of
junk that I gleaned from yard sales and the dump. However, I think I'm
going to have to actually start investing some extra care when I put it
together for the next time along with the junk attitude came the solder it
all together and see if it works attitude and that doesn't work very well I
found out! Lol I made the primary coil nicely with a piece of Corian
countertop and quarter inch copper tubing spaced half inch apart. The
secondary is also well made and sealed with an epoxy type resin and there
are no penetrations of the 30 gauge wire going through the non-conductive
PVC that it is wrapped on. However, I didn't do very good with mounting the
base or the top load and will do better next time. I think the biggest
problem I have with it is the connections being of contact nature rather
than being built to have the most surface area contact. Other words, the
secondary wire terminates at the top under aluminum foil which has been
taped down around the outside of the top with silver tape and the top load
sits on top of it with nothing actually holding it on. I figured it would
work and I could see some sparks and it does, but I know it can be a lot
better and it should be more solid anyway in case something were to knock
it off. Dryer duct is not the best thing to use for the top load, either
wrapped around a aluminum pie pan. This time around I am preparing to use
some smooth flexible pipe as the form and then carefully coat it with
something conductive... Aluminum tape was my first thought but I'm leaning
towards using a graphite paint because it will go on perfectly without any
break our points unless I want them. With the two transformers I have being
of different voltage, I am very skeptical that there's no way to combine
them without letting the smoke out of them even with their primaries
dancing to the same drummer.... But it would be really nice to have more
amperage than just thirty milliamps.
Thus I am planning on trying two MOTs instead as a source per what I read
by www://loanocean here in this thread. He is now using four MOTs, but his
first coil runs fine with two of them so it seems like a good new beginning
for me. Since there is now some burnt spots on my secondary from breaking
out on the sides, I'm also wondering a new secondary coil. This time with
the mounting lug in place and a copper strip for the connection to the top
load. I want to have all the connections being top notch and without
oxidation this time, and I'm also redoing the primary so that there is
space beneath the coil to tap into it..
Does anyone think it would be beneficial to weld the cores of the MOTs
together with one primary and three secondaries stacked together in series
with layers of mica between them? I did a similar thing to make a cheap
welder with four MOTs except I retained all four primaries and they are all
stacked in parallel, each with separate switches to be able to add more
juice if needed and otherwise the unused primary is open, and put as many
turns of some quarter inch thick, 3/8" wide ribbon wire on the rest of the
remaining space-i think I got seventeen wraps and that was incredibly
difficult to do around a wooden form, let alone getting it all stuffed into
the transformer itself! But it works great and usually only takes two or
three of the primaries to weld with eighth inch sticks...I still have those
secondary coils and two more microwaves I haven't rendered yet. That would
provide more than enough power though!
Anyway, I'm actively reading posts but haven't even introduced myself yet
as a fairly new member so "Hello my name is Patrick" .. I'm recently
retired and discovering electronics in all sorts of fun things especially
high voltage and high frequency and the learning curve is akin to trying to
just take a swig of water from a fire hydrant! The more I know, the more I
know I don't know! I also need to make some kind of filter such as a "Terry
Filter" but haven't put one together yet.
Pictured is the beginning of my new 4 and 3/4 inch coil. I built a quick
little frame that has two treadmill rollers on it and it just so happens to
be that the wire follows the groove in the roller perfectly as the form is
rolled and works its way along at the same rate. There are no crossovers so
far and there will not be any either. But that accidental discovery makes
it fairly quick to wrap a coil. You can see there's packing tape on one of
the coils because I was experimenting with a Van de graaff generator
earlier.
On Tue, Feb 14, 2023, 6:40 AM Joshua Thomas <joshuafthomas@xxxxxxxxx> wrote:
> Correction: 16kV, 750ma, for $8.82 each. HVP16 series.
>
>
> https://www.mouser.com/ProductDetail/Rectron/HVP16?qs=lCPxyJiDM7z8v4UG4CMgbg%3D%3D
>
> I’m guessing they didn’t have these in the 90s, but I’m also guessing they
> didn’t have the 942CDEs either. The MOT diodes still feel like a better
> solution for that ignition-coil TC. Hit some scrapyards, find used
> microwaves. I can usually find discarded microwaves around town every
> weekend. Haven’t had one of them be bad due to rectifier yet.
>
> (Half the time: fuse. Other half the time: magnetron just won’t work.)
>
>
>
> On Mon, Feb 13, 2023 at 10:22 PM Joshua Thomas <joshuafthomas@xxxxxxxxx>
> wrote:
>
> > I disagree; MMCs are versatile in that you can build them in boards or
> > other cluster shapes, and then move the series-parallel tap points around
> > for the desired voltage and capacitance rating. That's pretty useful if
> you
> > make more than one coil, or your coil evolves over time. Also, if one of
> > them blows, you lose a $9 capacitor (the CDEs are expensive now!) versus
> > $40 or more for a doorknob.
> >
> > The only advantage I see to a huge string of small rectifier diodes is
> the
> > dirt-low cost. You also have to find some way to mount or deal with them
> -
> > in the article they're wrapped around PVC or something - and it ends up
> > feeling like quite the kludge. I'm also suspicious of propagation delay
> > along a long chain of rectifiers, and instantaneous charge limits being
> > exceeded. There's a few stories from colliers (eg. Gao, and Greg at
> > http://hotstreamer.deanostoybox.com/) who reported using strings of
> small
> > rectifiers that should have by spec been sufficient and had them go bad.
> >
> > I'd rather just pay for some appropriately sized rectifiers and use them
> > forever. I picked up some 15kV, 750mA chassis-mount recitifers from
> Digikey
> > before they got discontinued. Looking forward to using those whenever I
> get
> > around to doing a real dual-MOT power supply. Not too bad - $12 each, I
> > think?
> >
> >
> >
> >
> >
> > On Mon, Feb 13, 2023 at 8:55 PM <pupman.com@xxxxxxxxxxxxxxxxxxx> wrote:
> >
> >> That's a cheap jab at an article from over 2 decades ago.
> >>
> >> MMCs are just as retarded as a string of cheap, available diodes when
> >> you can just get better capacitors.
> >>
> >> On 2/13/2023 6:20 PM, Joshua Thomas wrote:
> >> > Some of that article is genuinely hilarious.
> >> >
> >> > “The output of each ignition coil … is fed through identical diode
> >> strings
> >> > each composed of 45 series-connected 1 amp 1000-PIV diodes”
> >> >
> >> > Apparently this author never knew out the microwave transformer
> diodes!
> >> >
> >> >
> >> >
> >> > On Mon, Feb 13, 2023 at 6:57 PM Lux, Jim <jim@xxxxxxxxxxxxx> wrote:
> >> >
> >> >> On 2/13/23 3:17 PM, Ronald Reeland wrote:
> >> >>> Here are a couple links to the Popular Electronics November 1999
> issue
> >> >>> featuring Charles Rakes Tesla Coil article and plans:
> >> >>>
> >> >>>
> >> https://worldradiohistory.com/Archive-Poptronics/90s/99/PE.1999-11.pdf
> >> >>>
> >> >>> https://teslauniverse.com/build/plans/solid-state-tesla-coil-0
> >> >>>
> >> >>> Ron Reeland
> >> >>>
> >> >> The LU800 coil referenced in the PopElectronics article is still
> >> >> available. Around $15 depending on the source.
> >> >>
> >> >> I have no idea what the electrical properties are, but I imagine
> it's a
> >> >> fairly vanilla 12V coil.
> >> >> _______________________________________________
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> >> >>
> >> _______________________________________________
> >> Tesla mailing list -- tcml@xxxxxxxxxxxxxxx
> >> To unsubscribe send an email to tcml-leave@xxxxxxxxxxxxxxx
> >>
> >
> >
> > --
> > Joshua Thomas
> >
> > My new email address is: joshuafthomas@xxxxxxxxx
> > Please update your information if you have not already done so.
> >
> --
> Joshua Thomas
>
> My new email address is: joshuafthomas@xxxxxxxxx
> Please update your information if you have not already done so.
> _______________________________________________
> Tesla mailing list -- tcml@xxxxxxxxxxxxxxx
> To unsubscribe send an email to tcml-leave@xxxxxxxxxxxxxxx
>
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