Re: Strike rails/safety gaps IMPORTANT

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

Original poster: "cd by way of Terry Fritz <twftesla-at-qwest-dot-net>" <vbprg1-at-hotmail-dot-com>

Hey Im a first time coiler that got lucky and got my first coil to work.
I still have some minor problems with my strike rail and large primary to
sort out
but I am absolutely positive my safety gap saved me big time, well more
likely my neons

Everytime I had a funny/ wierd effect occur
ie jump from strike rail to primary (hope i have fixed this) or
secondary topload output strike on primary
or over-sparking in primary
EVERYTIME
The safety gap fired.....
I dont have a lot of experience but I'm pretty dam sure that a safety gap is
absolutely necessary unless you can build a coil
that has no wierd or odd effects occuring ever....not me Im lucky it works
at all...
and considering even Tesla had melt downs and wierd occurances....hmmm ball
lightning????
the safety gap is necessary...
Im probably lucky I am useing 2 cheap hard to destroy saltwater bucket caps
for my inital tests otherwise id probably already have destroyed parts of a
mmc, or exploded a expensive maxwell pulse cap ...

Chris Dowdy
12000v 60ma 4inchx20inch secondary confirmed 2 foot strikes to a florescent
light bulb
the arc turns from a cool purple to a bright white on contact :)


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, July 11, 2002 10:17 PM
Subject: Strike rails/safety gaps IMPORTANT


> Original poster: "Mr Gregory Peters by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <s371034-at-student.uq.edu.au>
>
> Hello all,
>
>
> I am SICK SICK SICK and tired of people saying "well, I don't use
> safety gaps and strike rails and have had no problems". You are playing
> Russian Roulette here. These devices don't only protect your equipment,
> they protect YOU!! Don't forget that a nice 200kV streamer makes a very
> nice conductive path for the output of your pole pig, or even the 240v
> mains! You DON'T want it getting into your control/power circuitry. The
> little effort in making a simple safety gap and strike rail are well
> worth the bother. These devices don't HAVE to look good. Fencing wire
> will do. I have included part of an old post from Richard Quick (A very
> successful old school coiler) below. I urge you all to read it:
>
> "Well I have seen a coiler or two who did not use contactors to
> remotely switch their 60 cycle mains. I have operated coils at
> 1.5 kVA without contactors. But let me tell you about the one
> time I had an incident that "resolved itself" inside the power
> cabinet. The experience changed my mind.
>
> Everything happened too fast to really give a "blow by blow"
> description, but basically what started it was the secondary
> discharge struck a primary that was not equipped with an RF
> grounded strike shield. The secondary discharge shorted the
> primary turns, and the main tank circuit ran away. By "run
> away" I mean that the oscillator shifted to a much higher
> frequency due to the arc shorted primary. The primary/secondary
> field flux collapsed when the tune was lost. All of the input
> energy, the field flux energy, and the energy already in the
> secondary, appeared to feed back into the tank circuit; in any
> case it looked like discharger had become a vacuum cleaner and it
> sucked in the five foot streamers. All of the conductors in the
> tank circuit sprouted six inch long sparks and corona at the same
> time the safety gap and capacitor terminals went to flames.
>
> What happened next I do not rightly know, but just when my finger
> hit the switch to shut the runaway oscillator down, there was a
> tremendous explosion inside the power cabinet. It was so bright
> that I had spots in my eyes even though I did not directly see
> the flash. The smell of ozone and electrical burn were strong in
> the cabinet when I opened the back to peer inside. At first I
> could not see anything wrong. But given the intensity of the
> flash, I was determined to disassemble everything if required.
>
> A careful examination of every inch of the wiring revealed a
> small hole in the insulation on the bottom side of a 60 cycle
> main. The hole was located about 1/2 inch from the first line
> filter, closest to the coil. Apparently kickback had made it
> inside of the cabinet and the impedance of the filter was
> sufficient that the kickback blew out the insulation and left the
> conductor entirely. The line filter, having been bypassed, was
> undamaged! Looking around some more I found fine arc tracks
> scored into the surface of the polyurethane coated plywood mount
> board. The arc had left the wire and traveled nearly four inches
> across a surface of poly-coated plywood while spreading into a
> "fan" of fine arcs that struck all along the main ground strap.
> The delicate fan-like spark pattern was nearly the size of a
> man's hand!
>
> As it turns out nothing in the cabinet was damaged. I tried to
> power up later, but a neon in my bank had gone south. I assume
> that the neon broke down internally, and the kickback had jumped
> to the 60 cycle primary.
>
> After all that I completely re-thought, re-designed, then re-
> wired everything. BTW, I just happened to be standing on an
> insulated platform, which I rarely do when I am at the controls.
> Had I not, I firmly believe I would have been jolted to my
> backside.
>
> Richard Quick
>
>
>
> Greg Peters
> Department of Earth Sciences,
> University of Queensland, Australia
> Phone: 0402 841 677
> http://www.geocities-dot-com/gregjpeters
>