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Re: [TCML] 6KVA first light

Hi John,

Sorry for the late reply. I just found a heap of TCML posts in my junk

If you want ground strikes, the answer is simple. Lower the coil :)

Seriously though, that double spark gap concept is brilliant. Have you
actually tried it? Yes, please do send the spreadsheet. My email address is

I'm assuming you just offset the charging elecrodes by 50%? I'm thinking
that it might be possible to retrofit my RSG with another set of stationary

The idea of a small charging inductor is very appealing. Since I will be
running 24kV in the tank circuit, the charging inductor was going to be one
of the larger challenges of the coil construction.

A very interesting idea. I am keen to chat more with you about this off
list (to spare the sanity of other members) if you are willing.



On Mon, Sep 2, 2013 at 1:00 PM, <jhowson4@xxxxxxxxxxx> wrote:

> Responding to a few of you at the same time,
> Stan,
> I wish I could go to the teslathon, but its just too far away for me right
> now. I could not even go to Ed's teslathon this year unfortunately.
> Pictures of my gap can be seen Here
> http://s139.photobucket.com/user/JHowson/library/Tesla%20Coils/Experimental%20DC%20Tesla%20Coil%20%20%20code%20name%20TRON/4%20Rotary%20Spark%20Gap
> One rotary electrode is missing in these pictures, but at the end of the
> video you can see both rotors in their place. Right now i have them set as
> a series gap (although 1/2 is not in use electrically) this was
> accomplished by drilling the one rotor with a 15 deg offset. Using my other
> shaft, does not have the offset.
> Greg,
> Yup, I was very pleased to be past the 6' barrier, it looks awesome with
> the sparks snaking though the air like that. But Ill be more pleased when I
> start getting ground strikes. (evil laugh)
> Looking back at my video frame by frame, it looks like One faint strike
> hit the foil i had covering my spark gap power cord on the ground. The foil
> was raised a couple inches, so i am not going to count that as my first
> ground strike. I set my standards high. lol.
> The DC coil topology i am going for was first explained to me by Steve
> Young actually (shout out to Steve).
> Basically you use two rotary gaps on a common shaft, but phased such that
> they don't become active at the same time. (or two stationary electrodes
> such that the same is true. for me i was trying to improve cooling and
> power handling, so I could use this gap for years to come. Thus why I have
> two gaps built into one housing. At first i was going to use, a single
> rotor, with a longer electrode. but meh, why not just make another rotor.
> So when gap one is active, the tank circuit is broken, but the charging
> circuit is energized.
> When gap two is active, the inverse is true, the Charging supply is broken
> and the tank circuit is energized.
> This allows a few things, because your not charging the cap while its
> active in the circuit you don't need to worry about shorting out the DC
> supply. That means you can use whatever BPS you want with no worries.
> secondly, because you dont really need to worry about the DC supply
> becoming shorted once again. You can get away with a much smaller charging
> inductor. only a few mH in my case.
> Using a filter capacitor on the supply, aids in charging the tank cap
> quickly, choosing appropriate charging inductance is necessary to ensure
> that the cap actually charges, but the current still remains under control.
> This also eliminates much of the noise that could back feed into the mains
> supply, because its physically disconnected while its doing its thing.
> i can forward you an excel sheet explaining a little better if you want,
> is the same one Steve hooked me up with a few years back. (this coil has
> been in the making for a while, lol)
> Steve,
> Hope you like your shout out above, =)
> Yes, I was planning on suspending a wire.
> I am also planning on building a better topload, I think my problem with
> tuning via scope last time, was that the aluminium tape is not all
> connected, so it gives wonky results.
> I saw someone recently fixed this using some EMI gasket so ill give that a
> go.
> Its gonna be a few months until i'm home again, but theirs still plenty of
> time to built a toroid at my new apartment =)
> Cheers,
> John "Jay" Howson IV
> "Why thank you, I will be happy to take those electrons off your hands."
> ----- Original Message -----
> From: jhowson4@xxxxxxxxxxx
> To: "tesla list" <tesla@xxxxxxxxxx>
> Sent: Sunday, September 1, 2013 1:04:08 PM
> Subject: [TCML] 6KVA first light
> Tested my coil with my 6KVA power supply last night.
> Got 80" sparks, which is pretty good for my only having tuned it to within
> one turn. Ill get out the scope and do it right next time.
> This coil will also be eventually converted to a dual Gapped DC coil. Now
> that I have the power supply completed, I just need to add my filter
> capacitor, inductors, diodes, etc and wire up the second gap. =)
> Unfortunately I am also moving to Maryland, so once again the forces of
> the world work against my progress. lol.
> But one day, the DC coil will be complete, maybe by spring time.
> Enjoy
> http://www.youtube.com/watch?v=QXVgENUq-4U
> Also, I think I am the first person to use the #12 THHN wire spool ballast
> method for a 240V system.
> details:
> Variac: 2 3.1Kva variacs wired with a common neutral and opposing legs of
> a 240V 4 wire feed
> Ballast: 2 500' spools of #12 THHN, one on each leg of the 240V line,
> limits 240V to exactly 30A, spot on.
> Transformers: 2 8400 Westinghouse potential transformers, primaries in
> series on the 240V with a common neutral, secondaries in series for 16.8Kv
> Output. (thank you John ie Futuret, these things are awesome)
> Primary: around 10 turns, Its free floating, so I can easily adjust the
> coupling via raising or lowering it with some blocks.
> Capacitor: 0.1 uf, 25Kv AC, made by Plastic Capcitors, speciically for
> tesla use i believe. (thank you David Reiben, this cap is sweet)
> ASRG Spark gap: 12 stationary electrodes (per side), 2 rotary electrodes
> (one for each side), 3000rpm max (600bps).
> Frequency: Secondary with just the bottom topload, clocked in somewhere
> around 84-87 KHz the last time I measured. Its obviously going to be a
> little lower with the extra capacitance, but I have not run the numbers yet.
> Thanks,
> John "Jay" Howson IV
> "Why thank you, I will be happy to take those electrons off your hands."
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