Original poster: "Peter Birk" <birk@xxxxxxx>
Fired up the coil after the changes suggested. Works better but still can
only draw about a 8 - 10 inch spark. No more sparks from the case. Noticed
a lot of sparking between the primary and secondary despite the quarter inch
thick plastic tube and the rubbery primary casing. Its much worse if the
spark gap is widened over about 1/8 inch. The primary coil is centered 4
inches from the bottom of the secondary. I wonder if raising the secondary
to bring the primary closer to the bottom will help this. Here's what it
looks like:
http://hot-streamer.com/temp/PeterBirk/IMG_0134_7_9_1.JPG
http://hot-streamer.com/temp/PeterBirk/IMG_0136_5_9_1.JPG
Stan I appreciate your comments. This list is dedicated to coilers turning
out technically and aesthetically elegant machines. I impose on your time
and patience because I need expertise not available elsewhere. This coil is
old but solidly built by a reputable company - CENCO. It survived 30 years
of use in a public school - I call that proof of design. If I can get it
going another 10 years several thousand students will see it and perhaps a
few will be inspired.
Thanks
Pete
-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Friday, November 03, 2006 10:39 PM
To: tesla@xxxxxxxxxx
Subject: Re: Atomic Laboratories 71869 Tesla Coil
Original poster: Stan <wsmg@xxxxxxxxxx>
Hey Pete,
I'm thinking that all the time you have been trying to get this
classroom science lab coil to be better then it was designed to be,
you could of wound a small coil with tunning capablities and had
more fun. Those were designed to be cheap and be safe for a
classroom(nothing wrong with that). I'm sorry to be so negitive, but
they aren't as inspiring as a real coil. Kids these days need to be
inspired.
Please don't be offended, I'm not an expert, I've only been coiling
for just over a year since going to D C's 05 Teslathon, but I have
come a long way. Check it out.
http://www.ispdial.com/SkyXPRess_net/MyHomePage/config.cfm?kName=wsmg
click on pictures to the left. That's just a few pics, we are working
on a DVD that will be much better. If you need a free nst I have a
bunch of 6k, 7.5k, 25ma with the wires that come off of them
(old) that work just pay the shipping. If your interested contact
me off list.
Stan
Tesla list wrote:
>Original poster: Mddeming@xxxxxxx
>In a message dated 11/3/06 7:16:53 P.M. Eastern Standard Time,
>tesla@xxxxxxxxxx writes:
>
>While it was apart I tried to measure the resonant frequncies with a >scope
>and signal generator. The primary dips at 217 kHz. The secondary dipped
at
>245 kHz. I found the top ball was not electrically connected. With that
>connected the secondary dips at 236 kHz. I wonder if anyone has any idea
of
>how to tune this coil. Note the primary is encased in rubbery compound.
>
>Thanks
>
>Pete from Virginia
>
>
>hi Pete,
>
>Since streamer formation tends to pull down the secondary frequency,
>you are probably very, very close to where you want to be without
>additional tuning.
>
>Matt D.
>
>
>