Re: Garage Physics

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "W.R. Langston by way of Terry Fritz <twftesla-at-qwest-dot-net>" <blangsto-at-iwvisp-dot-com>

Last night my son and I fired up our latest coil, a 12.75 x 52.75 -at- 20 ga. 
magnet wire type. We tried to get it going for Halloween, but in our haste 
someone wired the caps and gaps all in series. What we got that night was 
ear-rupturing cap discharges to the grounded terminal of our pig HV 
terminals. We pumped 240v 65a into that system and got appropriate noise 
and light out, but the only streamers were when the field collapsed as the 
system discharged to ground. Those were about 18 to 24 inch arcs, instantly 
here and gone.
I am the "old" physics guy, working in another field now, my son is the 
newly degree'd man in the lab, government lab at that, and he couldn't 
"see" how putting the gap in parallel with the pig would help out. So I 
just got out of the way and let him learn empirically what the excitement 
of the moment was blocking out of his mind for the moment. Any way, last 
night the opportunity came up for me to "find" the problem and bring it up 
in a non I-told-you-so way, rewire it as we were talking, and go for a test 
run. I am using three of the Maxwell caps the folks at Tesla Research sold 
me a year or two ago, and they work great. I set it up so we are way over 
cap'd, thinking it would be easy enough to drop connections as necessary.
As things turned out, when we got the gap running (4 moving, 2 fixed 
electrodes at 3600 rpm), primary taped at  turn 8 to start, 14,400v in to 
the gap and cap, we got 8 footers visible in evening light. A bit of 
playing with the tap (out to turn 12 of 18) and we were getting between 13 
and 15 footers, big, scary, thick blue and blue white arcs. That brought 
the whole neighborhood out to see what those crazy guys were up to now. We 
are putting this into the lasers, accelerator, TC and chemistry things we 
go around and demo in neighborhoods to try to catch the attention of kids 
on science and the fun of learning and gaining skills. It is a blast. What 
a great life... to be able to do that with your own son.
My point was that we caught him the same way when he was young. He went to 
university, physics, works in the field, married a physi-female (who is 
even now housebreaking the lad ;-), and I am looking forward to helping a 
grand baby, or 12, cut teeth on a pig and primary set up. It works! Living 
it out in front of the youngsters, and taking time to love them and spend 
money and energy with and on them works. Just to encourage whomever it may 
out there.

For LIFE and lightening in the desert of CA,
Bill L.

Tesla list wrote:

>Original poster: "Gregory Hunter by way of Terry Fritz 
><twftesla-at-qwest-dot-net>" <ghunter31014-at-yahoo-dot-com>
>
>A physics teacher from Middle Georgia College came by
>Thursday night, and he brought three of his students
>with him. He told me was teaching them about magnetic
>fields, but was having a hard time illustrating it. We
>agreed a Tesla coil would make a darn fine demo of
>magnetic coupling! The prof is not a hardware guy, and
>he makes no apology for it. His forte is classical
>physics and the underlying math. He is not a gadget
>guy, and doesn't want to be. Even so, he and his
>students very much enjoyed seeing my gadgets, and I
>got a hoot out of showing them.
>
>After a short lecture on Nikola Tesla and his various
>contributions to the world, I ran the little 4" x 24"
>coil for them using the twin MOT supply. It obliged by
>putting on a helluva show--multiple loud, snappy
>streamers out to 4 feet or so. I performed the trick
>with a 6" clear light bulb on a long stick of PVC
>pipe. The purple glow inside was excellent. I also
>walked around the garage with a 48" florescent lamp
>glowing in my hand, demonstrating wireless power
>transmission. Later, I laid the 48" tube lamp atop the
>toroid and lit up the coil. The tube flickered and
>sparks issued from each end, as expected. However,
>after a few seconds we got something unexpected. Hot
>little arcs developed at the points where the tube
>touched the toroid, and a pinkish glow began to spread
>down the length of the tube--like a bar of iron being
>heated with a torch and starting to glow cherry red. I
>quickly shut off the coil and we all examined the
>tube. The glass showed tiny fractures where it touched
>the torus, and the glass was permanently discolored a
>pinkish/orange hue for several inches, starting from
>the points of contact. Hmmm. Weird.
>
>Next, I fired up the 6" x 30" system driven by the
>11.5KV pole xfmr. I had put my big pool toy toroid on
>top to get longer sparks. I first ran the thing at
>only 240v/8A input. Performance was stellar--fat blue
>sparks in the 5 to 6 foot range (estimated)--the
>college kids wanted more. I opened up the arc welder
>ballast to 28A, and the resulting storm of streamers
>was absolute bedlam. In the confines of my closed up
>garage, the noise and light was a bit overwhelming for
>them--sort of like a big firework star shell that
>bursts a little too close to the spectators! The
>sparks were hitting my work bench, the ceiling, the
>floor, the walls, storage cabinets, etc., etc. The
>safety gaps were snapping like firecrackers. The big
>sucker gap sounded like an un muffled chain saw. The
>air reeked of Ozone and NOx! All I needed to complete
>the picture was a hulking cadaver laid out for
>re-animation!
>
>I really enjoyed my brief hour as a physics teacher.
>I'm glad the kids got to see what happens when theory
>is put into practice. I hope the Tesla coil demo was a
>positive influence. Who knows--maybe some of them will
>go on to become hardware types--mirror grinders,
>satellite builders, particle accelerator geeks, etc.
>
>Best Regards,
>
>=====
>Gregory R. Hunter
>
>http://hot-streamer-dot-com/greg
>
>_
>
>