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Coil 1 (revision 1)
Maximum spark length was about
5"
Throughout the next couple months we made some improvements. I acquired a 0-140VAC 7.5A variac at the Dayton Hamfest. We also tried a larger top load (the next size larger salad bowls), retapped the primary to 5 turns, and used three OBIT's. The maximum spark length was about 9". Unfortunately, I have no pictures of the first coil as it was when we first built it. After not too long I found all the great resources on the internet about Tesla Coils, including the Tesla List. I started to learn just how the coil works and how it could be improved. I began modifications that made the coils performance jump drastically. I obtained three 'doorknob' style capacitors from Dr. Resonance, which are actually pretty cheap and I didn't have much faith in them. I also built a new 'Richard Quick spark gap'. Allied Signs generously donated several used neon sign transformers. So, with all the new equipment, spark length increased to about 15" - 20". Here are some pics of Revision 2
(pics taken 11/97). Click to make 'em big.
Transformer: Neon Sign Transformer, 12,000V 60mA output Primary Capacitors: .012uF (total) rated at 30kV Primary Coil: 1/4" copper tubing, vertical helical wound, 5 turns, tapped at end Main Spark Gap: 6 gaps in series, .03" between each Secondary Coil: 3.5" PVC tubing, 15" high, and close wound with #22 magnet wire Secondary Terminal: 2 metal salad bowls making a spherical shape Miscellaneous:
we used #8 AWG copper wire for all hookups, and #6 AWG wire for ground
lead. Secondary coil is coated with a few coats of polyurethane.
Yet another revision... I was on a quest for perfection (like the Borg?). Never mind. Perfection is still a long way away... but this revision did bring it much closer. I figured that the coil would probably perform better with a much larger top load, but the primary coil was to small. We also had terrible arcing problems with this primary coil, so we built a new primary. It is a flat spiral coil of about 15 turns of #12 AWG wire, about 1/4" spacing. With this new coil we could put a big 6" diameter 22" wide aluminum ducting toroid on it or the even bigger 8" x 21" stovepipe toroid on it. This big toroid dwarfs the little coil! With either of these toroids maximum spark length increased to 29"! Here are some pics taken October '98. Click on them for a full size picture. The spark gap in the last picture is new also. It is a 'Richard Quick' style spark gap with multiple contacts and also forced air cooling. Here are some shots of some interesting arcing that I noticed in some of the pictures: This shot shows that the electrical connection between the top of the secondary and the toroid came loose and current was jumping about a 1/4" between them. Click here to see it. Funny that the arc length was still near the maximum 29" length. This shot is cool! Click
here to see it. The first arrow points to an arc that is several feet
away from the action. It is jumping between the ducting and the metal trim
of a doorway. The second arrow points to arcs that shoot along the
wall when the streamers hit the wall.
Transformer: Neon Sign Transformer, 12,000V 60mA output Primary Capacitors: .012uF (total) rated at 30kV Primary Coil: #12 AWG wire, flat spiral, 1/4" spacing, multi-tap points for various top loads Main Spark Gap: RQ gap with about 12 gaps, variable spacing & variable tap, forced air Secondary Coil: 3.5" PVC tubing, 15" high, and close wound with #22 magnet wire Secondary Terminal: 8" x 21" stovepipe elbow toroid (shown), also 6"x22" aluminum duct toroid Miscellaneous:
we used #8 AWG copper wire for all hookups, and #6 AWG wire for ground
lead. Secondary coil is coated with a few coats of polyurethane.
And another... Here are some pics (click to make
bigger):
Transformer: Neon Sign Transformer, 12,000V 60mA output Primary Capacitors: .012uF (total) rated at 30kV Primary Coil: #12 AWG wire, flat spiral, 1/4" spacing, multi-tap points for various top loads Main Spark Gap: RQ gap with about 12 gaps, variable spacing & variable tap, forced air Secondary Coil: 4" PVC tubing, 16" high, and close wound with #28? or 30? magnet wire (see explanation in the descriptions above. Secondary Terminal: 8" diameter Van de Graph sphere Miscellaneous: we used #8 AWG copper wire for all hookups, and #6 AWG wire for ground lead.
This webpage originally born on 3-14-98. Last updated on 9-7-01 Thank you for viewing my web pages! |
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