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Re: First big magnifier run
Tesla List wrote:
>
> Subscriber: nikki-at-fastlane-dot-net Sun Feb 2 17:27:19 1997
> Date: Sun, 2 Feb 1997 00:58:37 -0600 (CST)
> From: Bert Pool <nikki-at-fastlane-dot-net>
> To: tesla-at-pupman-dot-com
> Cc: jgore-at-cyberramp-dot-net, bemery-at-why-dot-net
> Subject: First big magnifier run
>
> Wild Bill Emery and I finally set up our large magnifier out in my driveway
> Saturday night and fired her up. We started with a 40 inch by 5 inch toroid
> on top of a 4 inch by 13.75 inch resonator coil (30 gauge). We video taped
> the runs, and then measured honest 90 inch strikes to the house and garage
> door frame. After running it, we found that I had failed to lock down one
> of the stationary electrodes on the rotary gap, and it had opened up to over
> 1/2 inch gap, and it still worked! We will redo the gap on our next series
> of runs.
>
> We first experimented with using the secondary in the driver as a
> conventional Tesla coil. It is only about 180 turns of 10 gauge wire on a
> 16 inch diameter pvc pipe, so inductance is not much. We tried the 40x5
> toroid as well as the 60x8 inch top, and all we ever got was sparks racing
> down the secondary - and this was with the coupling about as low as we could
> go without raising the secondary up (it weighs 107 pounds, so raising it up
> a foot or so is no small task.) We finally gave up on trying to use it as a
> conventional coil, and decided to use it as a driver, as it was so designed.
>
> What was absolutely incredible during this "conventional coil" attempt is
> that we had some extremely hot, violent arcs from the toroid down to the
> primary. Sometimes, but not every time when this happened, we got 23 inch
> flashovers from the bottom of the primary to the concrete driveway! We have
> the entire coil assembly sitting on top of 22 inch tall porcelain
> insulators, and the primary arced all the way to the concrete, jumping
> AROUND a 3/8 inch copper line run straight to my water main. I am still
> stunned at seeing this. I repeatedly watched this frame-by-frame on video,
> and it is weird. Apparently there is ground, and then there is ground. My
> main ground is 3/8 copper tubing screwed directly to a brass water faucet on
> the front of the house. The faucet is connected to a copper water line
> which immediately runs 30 feet under the yard to the water meter, and from
> there to the water main under the street. I dug up a section of the line
> from the meter to the house to make sure it was copper before I ever used it
> as my coil ground. I figure 30 feet of buried copper line connected to a
> buried water main is a damn good ground, so why would a strike to my
> concrete driveway just ignore a copper ground line connected to this superb
> ground? The arc had to bypass the best ground I can make and instead opted
> for some crummy concrete. I know the copper water pipe ground is adequate,
> as my coil is performing quite well. Those 23 inch strikes to the driveway
> passed within one inch of my ground and absolutely ignored it.
>
> Anyway, we will put the much larger top on the resonator coil next time and
> we should get much longer sparks. Our goal is to go beyond 10 feet, and
> with 7.5 feet on our first run (and this was using our first "best guess"
> primary tap setting!), I think we are well on our way there.
>
> I shot about half a roll of 35 mm film of the coil's driver construction,
> and I'll get this developed and scanned next week, I'll pass it on to Chip.
> I did not shoot any film of the coil running yet, only video. I'll take
> some stills the next time we run it. We're going to wind two new resonator
> coils, one will be a 12 inch diameter pvc pipe wound with 18 ga wire, and
> one will be a monster 16 inch diameter coil wound with 10 gauge. This is
> getting to be a lot of fun!
>
> We're running a 20,200 volt transformer, which is very loud on the rotary
> gap. I had several neighbors standing in their yards watching the show. I
> wish I had a large building to run this coil in, but unfortunately my yard
> will have to do. I think I'm moving it all to the back patio for my next
> test run to reduce the neighborhood interest. I figured on my first run if
> I even got it to break out of the toroid, I'd be doing good. I didn't expect
> 90 inch sparks and didn't want to generate quite so much neighborhood interest.
>
> Bert Pool
> nikki-at-fastlane-dot-net
Bert:
Sounds like you really had a great Saturday night. Good work with the
big sparks on the new coils first run! That is very interesting about
that 23" arc by-passing the system ground and going for the
concrete--what's the phone number of your concrete guy? :-) Just
speculating, but I wonder if thee might be some difficulty with the use
of that water system for your ground. I would suggest that a totally
separate ground using the good old 8" rods, at least two interconnected
would be an idea. I tried to keep all of my ground connections as short
as possible and I even use one of those 3' long watering spikes and soak
the ground before each run. I really had to mow that section of the
lawn alot! When arcs to the strike rail occured they were always very
brilliant hot arc and I didn't notice any RFI on the TV.
You can probably tell if your house plumbing is all PVC or copper just
on the hot water side by the size of the arcs off the water faucets???
Heck, it's 1:40 AM -- can't sleep, bad humor!
Hope to see your photo's as soon as you get them done--system sounds
really great.
Chuck