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Re: A 4" garage -- GNATS's first meeting
>>From chip-at-poodle.pupman-dot-comMon Oct 28 22:37:44 1996
>Date: Mon, 28 Oct 1996 22:35:38 -0700 (MST)
>From: Chip Atkinson <chip-at-poodle.pupman-dot-com>
>To: Tesla List <tesla-at-poodle.pupman-dot-com>
>Subject: A 4" garage -- GNATS's first meeting
>Greetings all,
>Last Sunday Dave Burman, Dave Baehr, and I got together in my garage for
>the first meeting of GNATS (Greater Niwot Area Tesla Society).
>The purpose of the meeting was to fire up coils of course.
>I have recently completed my rotary gap and was anxious to test it.
>After a few power cabinet glitches we got electricity to all the
>components and were ready to fire up my 4" coil.
>I fired up the rotary at about 700 breaks per second (12 contacts,
>running at a fixed speed of about 3500 rpm). As I turned up the power,
>the sound was significantly different from the static gap that I had
>used. As the static gap starts to fire, it starts out as a popping sound
>and increases in frequency as the voltage is increased. With the rotary
>gap, the frequency is constant (700 hz?) and increases in volume with the
>increased voltage. The sound is a robotic growling whine. As the
>voltage was turned up, the sparks grew longer and longer. It was
>wonderful. I didn't measure the length, but I estimate 4' sparks were
>flying for sure. The sparks were striking the garage door and anything
>with metal that was near.
>Acting on the advice from Dave Burman I had unplugged the garage door
>opener before hand. (More on this later).
>After firing up my 4" coil, we fired up Dave Burman's 6" coil. I didn't
>turn up the power too much before the thing was constantly sparking to
>something grounded -- garage door, opener, my coil sitting nearby, etc.
>It was apparent that my garage is not big enough for a 6" coil, but is
>big enough for a 4" one. That led us to devise a new garage size rating
>system: the maximum diameter of coil that can work in a garage. Thus, I
>have a 4" garage. Perhaps we can put a vaulted ceiling in it to get up
>to 6".
>After running Dave's coil, we plugged in the garage door opener and it
>didn't work which was distressing. However, Dave mentioned that his
>garage door opener had the same problem and it was the wall switch that
>was bad, and not the opener at all. It turns out that I had the same
>problem. To solve it he disconnected one of the wires on the switch and
>just touches it to the contact where the wire was screwed down. Weird
>circuitry in that little switch.
>Despite my size restrictions, I'm chomping at the bit to start on the new
>6" coil.
>A word or two about the rotary gap -- I used 1/4-20 brass acorn nuts for
>the moving electrodes and 1/8" tungsten rods for the stationary ones. I
>did notice a little erosion on the tips of the rods, but nothing
>excessive. The holders for the rods are turned from aluminum rod about
>1.5" diameter. They have a 1/8" hole down the center and are threaded at
>one end with a 1-8 thread. This allows me to only expose about 1/8" of
>the tungsten rod and provides a large radiating surface to keep them
>cool.
>We took pictures which I'll post oncd they get back. I'm also going to
>post pictures of the rotary gap, once I get them scanned. (The scanner at
>work is flakey, but one of our list members offered to scan them for me,
>so we'll see.)
>All in all, a great afternoon of coiling. All I can say is "goodbye
>neons"
>Chip
>=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
> Chip Atkinson
> http://bhs.broo.k12.wv.us/homepage/chip/info.htm
> --- Everyone is someone else's weirdo. ---
>=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Chip,
Good going! : ) I look forward to seeing your photos. One question,
since your garage is too small for anything larger than a four inch coil, why do
you only have your sights set on a six incher. If it is one that will have to be
wheeled outside anyway, why not think big! How about at least a ten incher,
maybe twelve, on easily obtained PVC pipe. Now that you have a good rotary
and pole pig happening, all this power needs somewhere to go.
Just to save some time. Yes, my chokes will work with a pole pig
application, but I'm not convinced that with an oil filled pig, that
you really need a choke, or any other secondary protection for that
matter except perhaps a horn safety gap, and a strike rail over the
primary.
regards,
rwstephens
[ Well, I have a 6" coil form. However, you are correct. This is causing
my wife to get eye-strain (from rolling them) :-) -- Chip]