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RE: Gerry's coil pictures
Original poster: "Jeremy Gassmann" <gmann-at-fuse-dot-net>
You have put great workmanship into this coil and you are getting
excellent results in spark length. I am using 4 - 15 kV 30 mA NSTs and
I think I am barely getting 3' arcs if that. Of course I have a
4.5"x22.5" secondary with only about 900 turns - that could be my set
back. If you ever get the chance, I am sure some of us on the list
would like to see more detailed construction pictures such as the top
load mounting scheme you use as well as you component layout. Keep up
the good work!
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Saturday, June 05, 2004 10:12 AM
Subject: Re: Gerry's coil pictures
Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net>
A friend of mine took the photos with a 6Mpix camera and I don't think
did any post processing. I sent them the way I got them and didn't
think about that.
The coil is 8x36 on an acrylic former wound with 1440 turns of 23gauge
single build formvar. Prewinding coat on the sanded former is shellac
there are 6 post winding coats of polyurythene. I did not sand the
the former. The topload is a 6x24 toroid by D&M (they did a great job)
is mounted on an acrylic tube that slides into another acrylic tube
(friction fit) so the toroid can easily be raised (lowest position in
picture). The tube is placed in a hole in the bulkhead capping the
There is another solid bulkhead of acrylic about 5 inches down from the
of the former for this tube to rest upon.
The primary uses 1/4 inch CU pipe with 1/4 inch space and is designed to
raised or lowered 1 inch from the bottom turn of the secondary. The
rail is at a fixed height and with the primary at its lowest (and
position, sits 3 inches above the primary. I haven't yet adjusted the
primary height for k optimization. Currently there are 20 turns max and
tapped at 20. Cp is 16.7nf (2 strings of 14 - 0.068uf and 1 string of
0.1uf CDE caps). I'm using a static gap made of 1/2x3 inch pipes and 9
of 35mil each. Safety gap is set to just not fire with Variac at
have two 100 cfm fans blowing directly down onto the gap (like a Terry
where segments are epoxied onto an acylic piece). During operation, the
safety gap seldom fires and the main gaps barily get warm.
Power is two 15/30's in parallel with the Terry filter physically placed
right between the two. The NST's are grounded to RF ground (stake in
ground) and not connected to mains ground. On the back porch, I'm
into a 20 amp line with GFI circuit breaker and so far it pops only once
run; it has always randomly popped even with little load so I do think
circuit breaker has always been weak. I'm currently not using PFC nor a
Next, I plan to switch to SRSG and see how much more power I can draw
the current power source. Then I plan to add two more 15x30 NSTs and
> Original poster: "Tom Luttrell PWRCOM" <tom-at-pwrcom-dot-com.au>
> Top stuff! That's a good looking coil too, very nicely finished.
> What were the coil specs?
> PS: Taking digital photos is only half the story. Post processing is
> also required in a majority of cases. The first picture improved
> dramatically when "Auto-balanced" by Photoshop. I'd show you the
> but I can't get to my web space from behind my employer's firewall.
> > Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
> > Hi All,
> > Gerry sent me these nice pics of his coil!
> > Nice night picture of Jerry's coil:
> > http://hot-streamer-dot-com/temp/48%20Inch%20Streamers.jpg
> > 59 inch arc with witnesses ;-))
> > http://hot-streamer-dot-com/temp/59%20Inch%20Power%20Arc.jpg
> > Gerry with his coil:
> > http://hot-streamer-dot-com/temp/The%20COIL.jpg
> > Cheers,
> > Terry