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RE: [TCML] Stuck at 36"

Hi John,

Although you have a fair sized farm of NST's, please keep in mind that the
total "power" and drop across the gap out is related to the voltage out (IE:
180ma * 7500volts ~= 1350watts out, less losses. 36" is pretty cool.

My 8" coil which uses a blown gap and also has a 15 degree, conical primary,
with similar coupling, gets about >68"<72" to a vertical copper pipe.

This is with (2) 15KV@60ma ~= 1800watts. I think the higher voltage and
power, less gap losses, MMC, and larger coil diameter helps much here, which
is of course a budget issue. It is hard to guess the efficiency of your
capacitor bank. Tesla did not have access to modern pulse capacitors as we

I agree with Bill that you may benefit from tighter coupling. This is not so
hard to do. Cut the tubing and find a suitable 1/2" to 3/4" long brass screw
and cut the head off. Try using a small rat-tailed file to prepare the
inner-side of the tubing and solder with a high power soldering iron or a
propane torch. 

Please use Bart Anderson's wonderful JavaTC
http://www.classictesla.com/java/javatc.html to verify the optimum coupling
< = K=.14 and maximum IDEAL spark length that MAY be achieved.

Best Regards,
Jim Mora

-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of johnbrooks@xxxxxxxxxxx
Sent: Saturday, January 10, 2009 9:40 PM
To: Tesla Coil Mailing List; A
Subject: Re: [TCML] Stuck at 36"

hello bigjohn,the first thing I notice is the
primary ID is about an inch or so too big.
On Sat, 10 Jan 2009 23:39:50 +0000, b.jbohn@xxxxxxxxxxx said:
> Hello everyone, first time here (great site!).  I've built a coil that
> refuses to put a streamer past 36" to a grounded plate suspended
> vertically at the top of the secondary.  Occassionally I'll get one
> 41-42".
> I'm using NST's 1@60Ma 7.5kv 4@30Ma 7.5kv all hooked together.  I think
> they're all okay because if I remove any one of them from the system
> performance diminishes.
> The secondary coil that I've had the best luck with is wound on a 5-1/4"
> varnished paper tube winding length 22-1/2" the wire is .014 or #27
> magnet it's 1,607 turns 2,208 feet.
> My capacitors are a mixed batch of homemade HDPE plate type.  
> Caps #1 & 2 each contain aluminum plates 10 x 12" 16 plates each .090
> HDPE between each plate
> Caps #3 & 4 each contain aluminum plates 4-1/2 x 9" 40 plates each .060
> HDPE between each plate
> Cap #5 rolled type in oil .01583 MFD
> All capacitors are in oil.  
> My spark gap is a segmented type with 10 copper tubes 7/8 OD 5" long
> total space between gaps is .150" just enough so the transformers can
> break.
> The gap is also blown with a fan.  
> My primary is a 1/4" copper tube conical 15 degree 14 turns 23" OD 7-1/2"
> ID seems best tapped at 12 to 13 turns.  I'm using a spun toroid it is
> 4-1/2 x 18" that size seems to work the best although if I put a 6"
> sphere on top pretty cool stuff happens (the streamers jump around the
> toroid and ball).  I have other secondaries that I've tried but this one
> is the best.  I have looked at other coils on this listing and other
> websites and I think mine should be doing better than 36".  Any input
> appreciated!
> Bill
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla

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