Subject: Ground Currents
From: richard.quick-at-slug-dot-org (Richard Quick)
Date: Mon, 6 Mar 1995 23:42:00 GMT
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Quoting Richard Quick:
RQ> Ahh, another interesting function of Tesla systems. As much
RQ> as I post on this subject, it is hard to make people
RQ> understand until they actually experiment. The ground is not
RQ> at ground potential when a Tesla coil is in use: the ground
RQ> is hot. If you doubt the validity of this statement, ground
RQ> a lone secondary coil that resonates at your system fre-
RQ> quency to the system ground and fire. The bare secondary
RQ> will resonate to good spark on the ground current.
Quoting Jim Oliver:
JO> I would like to understand this properly. By "system ground"
JO> do you mean the "large buried conductor" out back ?
Yeah. I use the term "system ground" to mean the "dedicated RF
JO> Are you saying that you have two identical secondaries, one
JO> connected to system ground and the other connected up into
JO> the Tesla <tank> circuit ? Then fire the coil, and watch
JO> arcs coming off the other secondary ?
That is what I mean, though "tuned secondaries" is perhap better
wording than "identical secondaries"; they need to resonate at
the same frequency. It is even possible to get LONGER sparks off
of the "free" secondary coil sitting by it's lonesome out in the
backyard (with nothing near but a short strap connected from it's
base to a copper pipe buried in the earth), than it is off of the
system inside that is processing the energy for the experiment.
(Talk about a run on sentance)
JO> One of my problems here is that we lack a real circuit
JO> diagram of all these things. I know you have posted some,
JO> but not yet (that I've seen) in their entirety. It's very
JO> difficult to show circuits in ASCII, bloody difficult. Maybe
JO> we should have a GIF or (better) a Postscript (or Ghost-
JO> script) file circulated of the main ideas of circuits
JO> incorporating all the ideas talked about, stuff like power
JO> factor caps, safety gaps, chokes, and guard rails etc and
JO> all their earthing circuits as well.
I do my best. The most recent GIF circuit diagram that I have
done pretty much shows everything from the breaker box to the
discharge terminal. I know it has been bounced around, and
Kristian Ukkonen has placed the GIF, with the text outline, into
the ftp site. Along with this GIF he included GIFs (and text)
detailing my HV RF choking and safety gap layouts. The only
things I missed in this series were the pfc caps and the strike
rail protecting the primary.
Now back to the experiment:
1) You need a Tesla coil system: Working Tesla coil with power
supply, tank circuit, secondary coil, discharger, and a HEAVY RF
ground. It is really nice to have several various sized
dischargers to make this experiment as effective as possible. You
will see me refer to this below as a: "coil system", "transmitter
coil" or "ground current transmitter".
2) Then in addition to coil system above you need: another
secondary coil (just a coil), some different sized dischargers,
and some ground strap with a clamp connector. You will see me
refer to this as simply a "free resonator".
Due to the practical differences in frequencies between the
ground current transmitter (see #1) and the free resonator (see
#2) it is best to use two coils of different sizes to get a good
frequency match. I will explain this more shortly. I like a coil
system (#1) using a 4 inch diameter secondary for the trans-
mitter and a 6 inch diameter coil for the free resonator (#2).
The experiment can be performed with a 6 inch diameter coil in
the transmitter (#1) and an eight inch diameter coil for the free
resonator (#2), but you have to be careful about your peak
powers. You do not need much power for this to be a very
effective demonstrative experiment.
The first part of this experiment is easiest. Set up your Tesla
coil system (#1), tune for maximum power and spark, and fire
away. Take your lone secondary coil (#2) and ground it to your
system ground. Change dischargers on your lone secondary (#2)
until the coil frequency is brought into resonance with the
transmitter system (#1). This will require a very small
discharger (possibly even none) if you are using the different
coil sizes as I outlined above. The free resonator coil (#2) will
spark, or at the very least will light bulbs, when it is grounded
to your system ground: when properly tuned I get at least 6
inches of spark. It is sparking because the transmitting coil
system (#1) is producing heavy ground currents that are conducted
through the ground connection to the free resonate coil (#2). The
free resonate coil (#2) may even be placed quite some distance
away, and grounded independently. It clearly shows a "hot" ground
while a Tesla system is connected to it and powered up.
To really demonstrate the effectiveness of ground current
transmission it is necessary to prevent spark breakout from the
air terminal on the transmitting coil system (#1). To achieve
this the transmitting coil system (#1) must be loaded with a very
large discharger. Using reduced capacitance, a large toriod, and
a large number of turns on the primary; it is possible to regain
the system tune (#1) at low power, and not have any spark
discharge. To verify tune, use low pressure bulbs at a distance
or draw spark with a grounded probe. It would be advisable to
operate this transmitter system in a Faraday cage to prevent
unwanted, and possibly detectable, RF radiation. Firing in a
basement will help.
Now with the coil system (#1) loaded with discharger, properly
tuned, and firing but not producing spark: where is the energy
going? It is not able to radiate near enough energy to dissipate
these peak powers, even if operating at a reduced voltage with
reduced capacitance. The energy is going to ground, and the
ground becomes a hot terminal.
Retune the free resonate coil (#2) to the new system frequency of
the transmitting coil (#1). This is easily done by using various
dischargers which will reduce the resonate frequency of the coil
(#2) until a match with transmitter coil (#1) is achieved. Ground
the free resonate coil (#2) to system ground. It will resonate to
spark: and not just any spark, but goodly hot streamers and
strikes will come off the discharge terminal if you are even
close to resonate tune. These streamers, sparks, and strikes can
even exceed the length of discharge that can be pulled off of the
transmitter system (#1) with a grounded probe. Why? Because free
resonate coil (#2) is allowed to resonate unrestricted by the
primary/secondary field flux of the transmitter system (#1).
When properly tuned, the free resonate coil (#2) may be used to
effectively pick up and resonate off of ground currents at some
distance. I can draw small sparks, and light bulbs bright enough
to easily read by, over 1/4 mile away from the transmitter system
when the free resonate coil (#2) is well grounded in creek water.
The transmitter can be enclosed in a Faraday structure, which
shows the the method of transmission is not through radiation,
but conduction of ground current.
I would really like to see some coilers in this group reproduce
and discuss some of this work. It is not hard, nor is it
complicated or expensive. All that is needed is to build up to
the point where you have at least two decent secondaries of
different sizes and resonate frequencies, three or more toriod
dischargers, and a decent high efficiency primary coil and tank
circuit. Stuff every serious coiler should have "off the shelf".
... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12