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Re: [] conical secondary (fwd)



---------- Forwarded message ----------
Date: Sat, 16 Jun 2007 20:19:41 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: [] conical secondary (fwd)

Hi Scott,

You asked if anyone considered it. Absolutely. Your comparison to a 
trumpet flare is good. The problem is of course building it. A few on 
the list have built flat secondary's (closewound) with a helical coil in 
the center. They reported better spark length results due to this. I've 
done the same with my closewound coil but I didn't have such great 
results. I had a lot of sparking from the center flat windings to the 
rising cylinder coil. Maybe a flared bottom on the helical portion would 
have prevented that. There is a coupling factor to consider when both 
coils are connected, but make abrupt deviation in geometry. Get that 
coupling too high, and the connection is non-existent. That was my 
problem. I of course realized this "after" the fact.

Your mention of a maggy setup is excellent. It's my opinion from my 
limited experience with my hybrid maggy and with flat coils that there 
is no need for a coil to coil connection (it's a waste of wire and 
limiting). All 3 coils could be built to resonate with each coil 
affecting the other coils capacitively and inductively. It's not easy. 
My hybrid maggy was a 3 coil system with all 3 coils in close proximity 
to each other (one on top of the other). The only chance I had was to 
model each coils affect to the other so I could get the design as close 
as possible. Beyond the basic resonant aspect, this also included mutual 
inductance performance for all 3 proximity's. One of the hardest coils 
I've built from a modeling aspect. Physically easy, mentally challenging.

Ideally, we would all love to build nice curves into our coils (bell 
shaped or whatever), but practicality always calls the shots (Shot 
Gun!). I've imagined some cool secondary's in my day dreams as most 
everyone else who coils has, but I've only built linear geometry (cone 
and inverse cone's are also linear geometry's). I'd love to see a 
non-linear coil someday. That is something I just have not seen. I don't 
know that it would make a lot of difference, but it would be cool to see it.

I termed my maggy as a hybrid maggy. It is not "tuned" as a standard 
maggy where L1 and L2 (driver coils) are some distance away from L3. My 
maggy required all 3 coils to be tuned as one would do with a classic 2 
coil setup (but coupling was allowed without negative affects to near 
0.3k. When they are in such close proximity to effect the other 
capacitively, that capacitance of L1 to L2 and L3, L2 to L1 and L3, and 
L3 to L1 and L2 must all be considered. Trying to get that right along 
with inductance's is a nightmare. Thankfully, I spent enough time with 
Javatc to use those topload objects to my advantage. In some instances, 
the top load object actually modeled L3, L2, and L1. That was the real 
trick! I'm sure I could do the same with a flat secondary, any geometry 
of primary, and a cylindrical L3.

I know one thing, a 4.5" diameter coil broke out of a 9" x 30" topload 
without any problem at all. And this particular show of the hybrid 3 
coil system was running with a shorted turn which I found out after I 
disassembled everything. Really fun project! BTW, four video's on this 
page of this coil and miscellaneous things about the coil.

http://www.classictesla.com/photos/hybrid/hybrid.html

Was this more efficient? In my opinion, nope! But it was fun!

Take care,
Bart

Tesla list wrote:

>---------- Forwarded message ----------
>Date: Sat, 16 Jun 2007 21:07:57 -0400
>From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
>To: tesla@xxxxxxxxxx
>Subject: Re: [] conical secondary (fwd)
>
>Bart and others,
>     Did anybody consider a flat secondary with a helical resonator in a 
>magnifier setup?  My thinking is that would give the absolute maximum 
>current (from the flat secondary) and potential (from the helical 
>resonator).  You could use a spiral primary, or a helical one, outside the 
>pancake secondary (which I would think in a conventional coil would give way 
>to much coupling, but since it's a magnifier, it may be Ok).  Correct me if 
>I'm wrong.  And what about a flared secondary like a trumpet sitting on it's 
>bell, probably very difficult to construct.  Just musing.
>Scott Bogard.
>
>
>  
>
>>From: "Tesla list" <tesla@xxxxxxxxxx>
>>To: tesla@xxxxxxxxxx
>>Subject: Re: [] conical secondary (fwd)
>>Date: Sat, 16 Jun 2007 17:10:26 -0600 (MDT)
>>
>>
>>---------- Forwarded message ----------
>>Date: Sat, 16 Jun 2007 15:12:25 -0700
>>From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
>>To: Tesla list <tesla@xxxxxxxxxx>
>>Subject: Re: [] conical secondary (fwd)
>>
>>Hi Marko,
>>
>>Yes, several coilers have built flat secondary's. Not a great deal of
>>coilers, but a few. Most are close wound secondary's and this was also
>>my first flat secondary. I used a lazy susan turn table to wind it. I
>>actually laid down two sided tape on a piece of acrylic so that when I
>>wound the coil (with 24 awg), the turns would stick to the tape and stay
>>in place. It worked out pretty good.
>>
>>I've also wound a 1/2 scale replica of Tesla's flat coil. This was very
>>easy to wind, but building the supports for it was a real labor
>>intensive thing.
>>
>>I first cut runners to lengths then used a router bit to groove a center
>>channel along the runners which would accept 1/8" thick plexiglas strips
>>(the actual runners to hold the secondary winding). I mounted those on
>>circular cutout plywood.
>>http://www.classictesla.com/flat/Img_3002fast.jpg
>>
>>When I cut the plexiglas standoffs, I made the turn to turn spacing
>>1/4". I taped off the wooden runners and used a clear 5 minutes epoxy to
>>glue in the plexi standoffs.
>>http://www.classictesla.com/flat/Img_3003_fast.jpg
>>
>>
>>I built a bracket that mounted the form to a tripod. The bracket allows
>>the form to pivot between horizontal and vertical. A bearing pulley
>>(form a Dodge 318 Idler pulley) was mounted to the form. This allowed me
>>to spin the form as I wound it.
>>http://www.classictesla.com/flat/IMG_3020.JPG
>>
>>A closeup of this simple bracket.
>>http://www.classictesla.com/flat/IMG_3021.JPG
>>
>>
>>Once I wound the coil, I removed it from the tripod and set it on a
>>table. Here is what the finished winding came out like.
>>http://www.classictesla.com/flat/Img_3462_fast.jpg
>>
>>I may remove a few inner turns before I'm finished, but now I'm trying
>>to figure out the best primary for this coil. I've got some copper
>>ribbon I was planning on, but I may change away from that.
>>
>>In the end, the coil will have a sphere mounted between 1 and 2 feet
>>center to the coil. It "will be", rim grounded with the hv end center to
>>the secondary.
>>
>>In any case, yes, we are playing with flat coils also. Just about every
>>coil type is being built by someone, somewhere.
>>
>>Take care,
>>Bart
>>
>>
>>Tesla list wrote:
>>
>>    
>>
>>>---------- Forwarded message ----------
>>>Date: Sat, 16 Jun 2007 11:34:58 -0400
>>>From: Marko Ruban <Marko@xxxxxxxx>
>>>To: Tesla list <tesla@xxxxxxxxxx>
>>>Subject: Re: [] conical secondary (fwd)
>>>
>>>Just out of curiousity.... has anyone ever built a pancake TC secondary
>>>(in a home built system)?
>>>
>>>
>>>
>>>      
>>>
>>
>>    
>>
>
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