nov-93.txt

To: tesla
Subject: nov-93.txt
From: chip (Chip Atkinson)
Date: Tue, 1 Nov 1994 13:17:39 +0700

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-01-93 16:43
From: Robert Taylor
To: Richard Quick
Subj: 10KVA TESLA COIL
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Wanted to pass along some reference material that may be of
interest. In addition to the _Tesla, Man Out of Time_ book,
Barnes & Noble also has _The Inventions, Researches, and Writings
of Nikola Tesla_ (edited by Thomas Martin--ISBN 0-88029-812-X)--I
picked this one up form them for about $15 w/in the last 6-9
months--think they still show it in their catalog.

The book is made up of transcripts of lectures & demonstrations
given by Tesla, & several chapters are devoted to the coil & what
he saw as its practical applications. Included are a lot of
technical details of his construction methods, as well as
schematics. Unfortunately, there is nothing included as to
the math that he used in design.

While looking at this thread, I noticed that someone made mention
as to a variety of spark gap designs. Some of this is covered-
-including magnetic & compressed air quenching.

I did some fooling around with these designs a few years ago, but
never got it to your level of development. Did not know the
details of the oil-immersion cap at the time so I built a
humongous Lleyden Jar cap for the tank circuit (after having
blown up a ceramic high freq xmitter cap, not a pretty sight).

However, did discover that a good power supply is a plain ol' 15
KV neon sign transformer (found some used ones at local sign
shops). My biggest problem was working out the inductance--never
could get the primary & secondary to sync properly--but it made
one heckuva broad-band spark gap transmitter.

Still interested in Tesla & his work. Quite a mind there.
(1:123/70)
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-03-93 20:42
From: Richard Quick
To: Robert Taylor
Subj: 10KVA TESLA COIL
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
RT> Wanted to pass along some reference material that may be of
RT> interest. In addition to the _Tesla, Man Out of Time_ book,
RT> Barnes & Noble also has _The Inventions, Researches, and
RT> Writings of Nikola Tesla_ (edited by Thomas Martin--ISBN
RT> 0-88029-812-X)--I picked this one up from them for about $15
RT> w/in the last 6-9 months--think they still show it in
RT> their catalog. The book is made up of transcripts of
RT> lectures & demonstrations given by Tesla, & several chapters
RT> are devoted to the coil & what he saw as its practical
RT> applications. Included are a lot of technical details of
RT> his construction methods, as well as schematics.
RT> Unfortunately, there is nothing included as to the math that
RT> he used in design.

Math? Tesla did not use math. Seriously. Oh, he used some
equations to give ballpark figures. But the numbers he was
working with were for the most part taken from machines he had
already constructed and were operating. Most of the math was not
figured out until years and years later. The mathematical
treatise on extra coil work was not derived until the 1980's,
Sloans work on resonators (mathmatical treatise) was not
published until the 1930's. Tesla invented and built, he left the
math for others to clean up later.

RT> While looking at this thread, I noticed that someone made
RT> mention as to a variety of spark gap designs. Some of this
RT> is covered--including magnetic & compressed air quenching.

The book is OK, but read it for generalities and direction only,
outside of the schematics (which are his more primitive circuits)
it should not be followed closely. We are in the age of plastics,
and Tesla was in the age of wood, and rubber (carbon rich and a
poor RF insulator). Some of the experiments are interesting, but
I have performed many better ones that do not require $300.00
(modern prices) custom made tubes.

RT> I did some fooling around with these designs a few years
RT> ago, but never got it to your level of development. Did not
RT> know the details of the oil-immersion cap at the time so I
RT> built a humongous Lleyden Jar cap for the tank circuit
RT> (after having blown up a ceramic high freq transmitter
RT> cap--not a pretty sight).

Good capacitance is a must! I too have built many, many, homemade
capacitors and leyden jars. Blew every one! Your not coiling
unless your blowing capacitors! Then when you get things worked
out to where the capacitors stop blowing, you start blowing
transformers. By this time though your usually running well over
a kilowatt and are getting (or have seen) some decent spark.
Then you start working with power controllers, and HEAVY RF
choking, next thing you know your in the big leagues.

The best capacitors for beginners are salt water types. Bottles
are filled with salt water, and placed in a salt water filled
pan. The pan is lined with alum. foil, and a long bolt or some
other conductor is placed in the bottle. The salt water in the
pan is one plate, the salt water in the bottle is another plate,
and the glass bottle is the dielectric. Oil can be poured over
the water to reduce corona loss. Tesla used salt water caps on
the Colorado Springs machine, and I have a friend running 5-8 KVA
with plastic bucket salt water caps.

RT> However, did discover that a good power supply is a plain
RT> ol' 15 KV neon sign transformer (found some used ones at
RT> local sign shops).

I recommend beginners start with 9000 volt neons, then move up to
12,000 volt units before jumping into the 15s. The 15KV neons put
too much stress on the capacitors (unless you are using glass
leyden jars, or salt water caps with thick bottles).

RT> My biggest problem was working out the inductance--never
RT> could get the primary & secondary to sync properly--but it
RT> made one heckuva broad-band spark gap transmitter.

You just needed to learn the ins and outs of tuning. It takes a
little practice. A lot of balancing is required to get optimum
performance. Coupling, spark gap quenching, terminal capacitance,
as well as the primary/secondary inductance all come into play.
Sounds like you made a good start, to bad you did not take it any
further. Thinking about picking it up again? With modern
materials, a little time and effort, and modern designs, you
would be surprised what you can achieve with coils.

RT> Still interested in Tesla & his work. Quite a mind there.

Me too, and I agree. Tesla was a man very far ahead of his time
and technology.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-04-93 19:17
From: Richard Quick
To: Robert Taylor
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
BTW,

I have read the book you mentioned in the post received here
yesterday. I bought it from Barnes & Nobel last month and have
read it cover to cover twice.

The books I mentioned earlier, (example _NICKOLA TESLA ON HIS
WORK WITH ALTERNATING CURRENTS AND THEIR APPLICATION TO WIRELESS
TELEGRAPHY, TELEPHONY, AND TRANSMISSION OF POWER_ ISBN 0-9632652-
0-2, from 21st Century Books, P.O. Box 2001, Breckenridge, Colo.
80424) is a much more informative work.

Tesla did not go public with much after he saw the tide of his
fortunes turning. He kept his more advanced work very close to
his chest. Even his basic experimental circuits used in
developing the Magnifier were not published until the 1970's, the
math not worked out until late in the 1980's, and the systems
actually re-tested (with the exception of Golka's primitive
efforts) until the last two years! Right now work on the
Magnifier is at the point where any serious hobbyist can make a
mark.

The book above is a candid interview with Tesla's attorneys in
1916 (after Wardenclyff), he talks, submits photographs,
sketches, and schematics; all of which is recorded by
stenographer. All documents submitted by Tesla are reproduced.

This book really cuts to the core. We see that Tesla used red
herrings, even from the start, to disguise the true nature of his
work. An example is his submission of photos and patent wrappers
of an alternator. The alternator was patented (#447,920 March 10,
1891) as the power supply in a "Method of Operating Arc Lamps".
Yet Tesla goes on to produce schematics showing it as the signal
generator for the first radio, AND shows how the circuit evolved
in a matter of months into a powerful lumped tuned circuit
transmitter.

He submits schematics of his experimental tank circuit used in
the New York lab prior to leaving for Colorado Springs, complete
with three phase synchronous gaps (never published or patented).
We see photos taken from Wardenclyff powerplant showing huge four
phase high frequency alternators, and text describing the
operation and performance.

The Colorado Springs notes are another example of Tesla
revelations. Tesla never intended those notes be published, and
we see circuits in there that are meaningless, until you add
perhaps a little note from the book mentioned top. We see the
circuit that Tesla used to create ball lightning in the lab
(Colorado Springs Notes pp 115,162), advancements made on the
three phase gap (but not showing the gaps, just the improvement).

Then we add information gleaned from the Corums' book _VACUUM
TUBE TESLA COILS_ (ISBN 0-924758-00-7) and we begin to see that
his later claims of particle beam weapons, worldwide power
transmission, robotics, etc. are not based on some "crackpot's
fantasy" (as Guy Daugherty would have some believe).

He completed all of the basic research, had an operational
worldwide transmitter (Wardenclyff, look at the powerplant
photos) though nobody had receivers yet. He had operational
remote control robots (ISBN 0-9632652-0-2, pp 157 {photo}, patent
613,809 11/8/1898!).

I guess what I am trying to say is that his lectures, published
explanations, even to some extent his patents are misleading, and
deliberately so. You have to dig into sources that Tesla did not
intend to become public, then you have to build and test these
systems, then you are on the road to his later secrets. But they
all seem to reach back to his 1/4 wave coil systems and the
lectures, for the roots. The problem is that the work he
presented in the lectures is now obsolete, both from a design and
engineering point of view. With exception of some of the
experiments, skip on to the material I have documented.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-05-93 01:25
From: Richard Quick
To: David Tiefenbrunn
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Well Dave,

I talked with the architect again today. Things are firming up
for a real lab.

The building so far is looking like this:

50' x 60' with 8' masonry walls and 8' sheet metal walls on top.
This gives a total wall height of 16 feet, with a slope up to the
center of the roof for a 20' peak.

The half masonry, half sheet metal wall was a compromise for
security, cost, and you'll never guess what else... My testing
shows an all metal walled building will induct, and large
currents will cruise through the structure. So masonry for the
first 8' feet seems a good compromise.

For electrical service I'm getting 480 volt 3 phase, 400 amps,
and 110/220 single phase 200 amps.

The building will have 4" x 15' galvanized pipe driven into the
ground before the slab is poured as an RF ground, and I plan to
extend it later. Thought I would drop you a line and let you
know, as I was pretty excited to see some drawings.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-03-93 13:43
From: Dave Halliday
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
RQ>Dave,

RQ>I got your package in the mail today, and your tape went back
>out. It is after the pickup time on Saturday, but you should
>have the tape by midweek.

RQ>Let me know when you get it, and what you think. I am sorry I
>had to cut a lot of material out, but two hours just doesn't
>seem to be enough time to give you the tour, show you some m
>techniques, and show all of the systems. I cut back on a lot
>of smaller test and prototype stuff to let you focus on the
>big coil.

GREAT! I will look forward to viewing it! Also, emphasis on the
big coil is perfect. 301-794-6496 (1:109/546)

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-05-93 02:22
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
If you are interested in making a high voltage, high current,
power supply, I can tell you how to do it for free....

First call the local neon shop(s) and tell them that your working
with Tesla coils. Ask them to hold all of their failed xfrmrs so
you can pick them up. Make sure you talk to the boss or foreman,
and tell them that you want dead units. I have never had a shop
turn me down for free cores. They are happy to get rid of them.

There are two types of failed neon xfrmrs: warranty units, and
old junk. The local shop must return units that fail within the
two year warranty period back to the distributor for credit. Old
junk (older than two years) you can pick up for free right from
the local shop, but I also scavenge from the distributor. Ask
where the failed warranty units go.

If you can locate the distributor who sells wholesale, and
handles failed warranty units, you have found a gold mine of high
voltage xfrmrs. The distributor removes the PLATE from the xfrmr
for return to the manufacturer, and throws the unit away. The
manufacturer credits the distributor for the plate, as the
shipping is too expensive. The cores go to the dumpster.

After locating your source of failed units, be selective. Try to
bring home the high current units. Ratings commonly used are 9
kv, 12 kv, & 15 kv, with common current ratings of 30 & 60 ma.
Once in awhile you will come across a 120 ma unit. I grab all
of the high current units (60 ma+) I can get in these voltages.

First test your units. Use wire with a 15 kv rating or better.
This wire can be obtained where you pick up the transformers.
If you ask they will usually cut you off a few feet for free.
I prefer using the solid polyethylene core from RG-213 coax, as
it will withstand the voltage with gobs of extra safety margin.
Draw an arc from the HV bushing to the case, one at a time.

About 50% of the "failed" units I pick up are just fine and need
nothing other than a clean up. There is nothing wrong with them.
Often shops get these units from signs they have dismantled, and
they just toss them into the junk pile with the rest. The other
50% are bad. Either one, or both, of the HV windings have broken
down. These units can frequently be repaired.

Remove all hardware, and insulators if possible. Take a hammer
and a chisel and remove the cases by splitting them down the
corners. Break off any stubborn insulators, but try to preserve
the lead wire. You are left with a block of tar. Set the unit
outside when it is very cold, and let it freeze solid overnite;
or place in a freezer or deep freeze until frozen solid. The next
morning, short the high voltage lead wires with a clip lead, and
connect 110 volts across the primary. Since the cores on these
transformers are shunted, they may be shorted without harm or
blowing fuses. Let the unit cook for 15-30 minutes.

Disconnect your leads, and with the chisel and hammer, chip a
groove around the block. You want to score a groove lengthwise
that will allow the block to cleave in two. Then starting from
one end of the block, chip until you hit the core, then do the
same with the other end. Pry and chip the tar away from the core
until the xfrmr is free. The core may then be disassembled, and
the windings removed and examined. Kerosene and a stiff brush
will clean up the windings and core of any remaining tar.

The "cold-cook" method is fast, clean, and works very well. Since
the tar is frozen it chips away cleanly. The "cooking" softens up
the tar around the core allowing it to release. The only other
ways I know to free the cores are long soaks in solvent such as
kero or gas, (the nasty waste does make a good crack filler),
or melting out the tar with external heat from a fire or oven.

Most units fail when the high voltage breaks down the tar insul-
ation. The resulting carbon track shorts the winding. Simply
removing the tar brings them back to life. Other times the coils
break down internally. In this case I discard the winding after
disassembling the core, and replace it with a good winding from
another unit of the same model with the same type failure.

While the core is apart, you can beef up the current output by
removing a few of the shunting plates between windings. Never
take out more than 2 or 3 of these plates per side, as the
additional power output will burn out the secondaries. Generally
I get about 70-75 ma out of 60 ma units after I have finished.

(Continued in next post)
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-05-93 04:13
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
(cont.)

Rebuilt units need a little protection from the high voltage
secondary outputs. The first thing I do is solder on a new lead
wire to the high voltage windings. The HV secondaries are wound
with very fine magnet wire, in the 30 ma units the wire is not
much thicker than a coarse hair. Once a good solder connection
is made, bed the connection and the first 1/2 inch or so of lead
wire to the top of the HV winding with hot glue or clear epoxy.
The lead wire need not be anything special, any thin insulated
stranded wire may be used. Heavy wire increases the chances of a
failed connection due to mechanical stress. When setting the unit
up to fire you simply have to route it on insulators.

The windings themselves are wedged against the core to prevent
vibration. I have seen wood, bakelite, and plastic wedges used
commercially. What I like to do is to soften up some 30 mil
polyethylene plastic sheet in boiling water, and heat the core in
a warm oven. I wrap dry softened plastic around the core and
gently force the windings down on it. Once cooled, the windings
have some insulation from the core, and they will not vibrate.

The base wire from the HV windings must be grounded to the core.
Use the original grounding point if possible, if not you may
split the core apart slightly with a thin blade and insert the
wire into the gap before you clamp the core back up. If required
you may splice on a small piece of wire for added length.

Neon sign transformers that have been rebuilt may be fired dry.
The tar used to pot the cores for neon use does not really
insulate well against the RF and kickback from the Tesla Tank.
The units last longer when they are freed of the tar potting. The
only other choice is to sink rebuilt units in mineral or xfrmr
oil which is a very good RF insulator. I choose to fire them
"dry"; it works, and there is no mess.

Neons may be run in parallel to deliver the current required to
fire medium sized coils, and I have run up to 4000 watts with
banked neon power supplies. The general practice is to run these
banks off of 240 volt feeds controlled through a variac. Neons
with matched outputs are run in pairs in these banks. The
primaries are paired up in series, and the secondaries are all
paralleled to the HV buss. Phasing is important here, and each
transformer must be checked as it is added to the bank to ensure
it is in phase with the other units. If an xfrmr draws an arc
from a lead wire brought to the HV buss, the primary or secondary
connections must be reversed.

Neons typically have an efficiency of about 50%, in that they
draw twice as much power as they put out. This problem can be
resolved with the use of power factor correction (pfc) capaci-
tance across the line. The pfc capacitors used are the same as
for alternating current motors. The voltage rating should be at
least twice the line current used, and I like a 4x voltage margin
for long life. The formula used to determine ballpark pfc is as
follows:
9
10^
C = Corrected kVA ------ 2
2(pi)fe^

This should read C = Corrected kVA times (10 to the ninth power)
over, (2 pi times f times e squared)

C = required capacitance in microfarads
f = frequency of applied voltage
e = applied voltage

CORRECTED KVA is determined by dividing the volt*amps (watts)
output of the neon sign xfrmr by 1000

Using a pair of rebuilt 12 kv, 60 ma neons, with 2 shunting
plates removed from the core next to each HV winding, and power
factor correction capacitance, you can get a nice 1.5 KVA Tesla
power supply with over 90% efficiency. Total cost: $5.00 for the
pfc capacitors, and a few hours of time.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-01-93 10:21
From: Guy Daugherty
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
RQ>But if everybody thinks I'm wacky, should I stop posting? I
RQ>don't want to waste people's time. I just thought you all were
RQ>interested.

I'd guess that the ones of us who are doing similar research are
completely engrossed with your findings and research- I think
it's interesting, though I fail to see the utility of what the
devil it is you're up to, as opposed to my productive reduction
of lifespan, i.e., posting smartass remarks in a few conferences
and running up the phone bill for dozens of sysops across the
globe. I'm curious what your end goal is, if you believe that
even if you can prove Tesla's principles and concepts to have the
validity his proponents trumpet, how could your break into the
lockup current utility companies have over the conversion and
distribution of electrical energy.

I have similar feelings about the use of dinosaur ooze for
internal-combustion engine fuel --hydrogen would solve the
pollution, supply limitation and toxicity problems-- but I
have no fantasy of it coming to pass in my lifetime. I say keep
posting. We're interested. Plus, it narrows down the amount of
territory we'll have to look for you in when something goes
horriblly awry. (209)472-0843 (1:208/216)

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-07-93 02:03
From: Richard Quick
To: Guy Daugherty
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
GD> I'm curious what your end goal is, if you believe that even
GD> if you can prove Tesla's principles and concepts to have the
GD> validity his proponents trumpet, how could your break into
GD> the lockup current utility companies have over the
GD> conversion and distribution of electrical energy.

We may never see this one, even if commercial feasibility is
proven. But you are taking a bit of a narrow view, that is all.
My personal goal is not only to prove Tesla's principals and
concepts (which I believe has already done as far as his patents
are concerned), but also for the pure search of knowledge.
Practical applications, something I think may be possible to
achieve, would be perhaps a true "high efficiency" laser. If we
have one, then someone will figure out how to employ it for
profit, maybe in fusion. Me, I am looking to spend money with
this, not make it.

You must be misunderstanding the breakthrough that the Magnifier
circuit represents. Just because Tesla saw one commercial
application for the circuit in a transmitter does not mean that
this is the only single use, or the only use Tesla saw. This is
definitely not the case. The circuit is a very, very, very
efficient RF power supply. It can be set up to provide RF
current, or voltage (or both) depending on the intended app-
lication. As a power supply for large tuned resonate loads there
is nothing equal. In effect the circuit is narrow band RF signal
generator capable of enormous powers. It is relatively cheap and
easy to build, and the design and components are easily modified.

The Magnifier was not recognized as a high efficiency, narrow
band signal generator until the mid 1980's; 90 years after Tesla
had industrial scale operational units, and a full ten years
after Tesla's Colorado Springs Notes went into print for the
first time. The photos published at the time (early 1900s)
only show, and the only thing people remember, are the sparks.
Yet in the opening pages of the Notes, Tesla clearly stated his
intended goals for the machine, he does not mention sparks.

In an era with no o'scopes, multimeters, RF detectors, or
stabilized RF generators (other than his); Tesla proceeded to
design, construct, and test, a narrow band RF signal generator
driving a tuned 1/4 wave resonate load to a voltage of 9.5
Megavolts with RMS currents of 1100 amps. Figure it out Guy,
that's 10.45 Billion watts. He did this with an input power
of 250 kVA, and so named the circuit "The Magnifier". The only
way he could judge the performance of the system was to tune for
spark occasionally.

The reason the system was so large was because physical size was
the only way to contain the energy in the system without break-
down. He had to keep his charge density low or he lost energy. He
did not have plastic film type pulse discharge capacitors, poly-
ethylene core coax, PVC jacketed wire, or any of the dozens
of other modern materials I use daily.

When Tesla perfected the circuit, the only 1/4 wave resonator
in existence was the resonate coil. We now have coaxial, tapped
helix coaxial, and pure cavity geometries. Tesla never mentioned
coherent radiation, and now we have lasers and masers. The
Kapitza fusion experiment and the maser are examples of modern
applications of resonate loads. Both are cavity type 1/4 wave
resonators driven by signal generators.

In my recent research I ran across an article, "Cavity-Coupling
Investigation for the Phermex 50 MHz RF Accelerator", by E.W.
Pogue and F.R. Buskirk, IEEE Trans. on Nuclear Science, Vol. NS-
32, No. 5, October, 1985, pp 2852-2853.

The boys at Phermex seemed really excited to discover an increase
of performance in the accelerator when run off parallel drivers.
Yet Tesla shows the SAME IDENTICAL CIRCUIT, and at least three
variations, with notes relative to the performance and character-
istics of each in The Colorado Springs Notes in 1899!
See Colorado Springs Notes, pp 153-156, mid August 1899.

The circuit is precisely identical, the only differences being
the frequency of operation and the geometries of the resonator.
Tesla BTW was running powers an order of MAGNITUDE greater
the Phermex team.

The magnifier is a very efficient signal generator, NOT a
transmitter unless you CHOOSE to set it up as one. The entire
purpose behind the magnifier circuit, it's only true function, is
to drive resonators, not to transmit power.

So lets forget the sparks for a moment, and lets forget global
transmission of power. Why not hook the system to a tuned 1/4
wave resonator designed as a laser tube? A system 1/10th the
power of Tesla's Colorado Springs oscillator would deliver a
billion watts. With modern materials the size could be reduced
greatly because we can insulate with plastics. In real dollars
the cost is cheaper than Tesla's because we can tap the
industrial surplus markets; transformers he paid thousands for
then, I can buy surplus for a few hundred.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-03-93 22:00
From: Bob Stephenson
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
GD> Well I have a Jacob's ladder on an old theater marquis
GD> neon transformer. Really makes the kitty stop and pay
GD> attention. Worries people who see it, too. My inner Beavis
GD> loves it. ^^^^^^^^^^^^^^^

Oh man, I love it....Thank you! Bob (1:2604/109)

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 05 Nov 93 02:22:00
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ

If you are interested in making a high voltage, high current,
power supply, I can tell you how to do it for free....

Remove all hardware, and insulators if possible. Take a hammer
and a chisel and remove the cases by splitting them down the
corners. Break off any stubborn insulators, but try to preserve
the lead wire. You are left with a block of tar. Set the unit
outside when it is very cold, and let it freeze solid overnite;
or place it in the freezer section of the fridge. The next
morning, short the high voltage lead wires with a clip lead, and
connect 110 volts across the primary. Since the cores on these
transformers are shunted, they may be shorted without harm or
blowing fuses. Let the unit cook for 15-30 minutes.

(Continued in next post)

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 05 Nov 93 04:13:56
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
(cont.)

This should read C = Corrected kVA times (10 to the ninth power)
over, (2 pi times f times e squared)

C = required capacitance in microfarads
f = frequency of applied voltage
e = applied voltage

CORRECTED KVA is determined by dividing the volt*amps (watts)
output of the neon sign xfrmr by 1000

I have unpotted dozens of neon transformers from many different
manufacturers. I have tried to make this as informative as
possible, and have checked it over for mistakes. If I have erred,
or was not clear on something, please let me know. Use common
sense, and don't expect the first attempt to work out. On my
first attempt I managed to destroy a HV winding during the
unpotting, as I did not know where the windings were located on
the core. But once you see one core unpotted, with minor
differences, you have seen them all.
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-04-93 22:11
From: David Tiefenbrunn
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
On 10-30-93 Richard Quick wrote to Guy Daughterty...

RQ> But if everybody thinks I'm wacky, should I stop posting? I
RQ> don't want to waste people's time. I just thought you all
RQ> were interested.

I'm interested. On another un-usual experimental topic,
have you ever seen / read about / or heard of a rail gun?
Dave (1:320/5967)

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-06-93 19:22
From: Richard Quick
To: David Tiefenbrunn
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ

DT> I'm interested. On another un-usual experimental topic,
DT> have you ever seen / read about / or heard of a rail gun?

Sure, two different types.

Steve Hanson runs a particle accelerator rail gun in his
basement. It is small, but it cooks!

He has extensive vacuum equipment, and the basic setup looks like
this:

Two copper rods form the rails. They are set up in parallel bar
fashion with the bases mounted in an insulator block. At the base
of the rods, near the insulator, he wraps a tungsten filament
removed from a common light bulb. He places a glass cylinder,
like an elongated bell jar, with a target mounted in the closed
end, over the rails. The jar is sealed at the base and pumped
down to a hard vacuum.

Two high current lead wires are connected to the rails. They are
epoxies into the insulator base so as to be air tight. He takes a
HVDC power supply and charges a massive capacitor bank. He throws
the switch, and BANG! the tungsten is vaporized.

The plasma is highly conductive, and maintains a current flow
between the rails. The high current produces electro-magnetic
force which propels the plasma under high acceleration down the
rails and into the target. A regular microscope shows the plasma
impact damage on plate glass targets. It really sinks the
tungsten into the material.

Steve publishes a journal in which he covers his work. You may
write to him at: 35 Windsor Drive, Amherst, NH. 03031.

The other type of rail gun uses a monorail system. A "bullet" of
conductive material is loaded onto a single nonconducting rail
surrounded by heavy coils. The coils are energized by a timed
capacitive discharge. A special rotary gap with varied spaced
electrodes may be used, but recent work points to computers to
control to pulses. Timing is most critical.

The heavy current flow through a coil induces a current in any
conductive material, in this case the projectile. The circulating
currents in the projectile produce a magnetic field, which repels
it from the coil. As it passes the next coil down the rail, the
second coil is pulsed and so on. Since the current and voltage
from the capacitive discharge is high, the forces imparted to the
projectile are great. I believe the speed of sound has been
broken by projectiles from small "hobby" guns.

I have not had contact with a working monorail gun. I have seen
several photos. Information Unlimited, P.O. Box 716, Amherst, NH.
03031, tel: 603-673-4730 (9-5) may have additional information on
monorail guns of this type.

Then there is this guy in California with a multi-gigawatt Taser
gun....

The commonality of these systems is capacitive discharge, and
power supplies. You must have HV pulse discharging capacitors and
a high current, high voltage, power supply to experiment in these
areas.
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-07-93 16:14
From: Richard Quick
To: Dave Halliday
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ-
DH> Hi Richard - again, thanks for the fantastic video! Loaned
DH> it to my dad this morning - he used to teach physics ( still
DH> writes textbooks ) and is a Tesla fan too...

DH> Anyway, I was wondering how you went about getting your pole
DH> pig - line xfrmr - and how much it set you back... I called
DH> our local City Light and they cannot sell them because of
DH> the EPA regulations. They actually ship them to some company
DH> overseas for salvage... I will try some of the smaller PUD's
DH> and see if they are not so "Politically Correct" <grin>

Well you can try the utilities, I did, with no luck:-( Unless you
are willing to climb the fence into their transfer yard and climb
back out, in the dark, with a 200+ lb. pole pig under your arm,
you will not get one there :-) I bought mine from:

Larry J. Rebman
The Transformer Bank, Inc.
University Technology Center
1313 Fifth St. SE
Minneapolis, MN 55415

Tel: (612) 379-3958, Fax: (612) 379-5962

The transformers they sell are brand new GE surplus, certified
PCB free. GE manufactures at their plant in Hanover, North
Carolina. Unsold units sit in the yard, and on GE's balance
sheet, for 5 years and depreciate. Once GE has depreciated them
to zero, The Transformer Bank buys them for 50 cents a pound.

The Transformer Bank enters all of the plate information from
these surplus pigs into their database in Minneapolis. They will
fax you the plate specs on any surplus pig in the Hanover yard.
Once you have chosen the xfrmr you want by comparing a few plate
specs, call them for a price, then send them a certified check.
The retail cost is a little over $1.00 a pound, so figure a 230
pound, 10 KVA xfrmr, will run about $250.00.

The Transformer Bank has a shipping contract with Consolidated
Freightways. The units are shipped directly from the Hanover
yard. The contractual rate is about 50% the normal retail rate,
and the Transformer Bank passes the entire savings on to the
customer. Figure about $50.00 shipping per 250 pounds.

My pole pig ran $303.00, including shipping, and was delivered to
me ten days from the date I dropped the certified check in the
mail to Minneapolis. It arrived still strapped on the original
pallet, and it had no dings, dents or chips. The pallet was
heavily weathered as one would expect, but once the pig was
cleaned up, it looked (and is) brand new.

The unit came with certification papers that match the serial
number on the plate, showing it to be PCB free. Copies of the
certification are on file with GE, so disposal or transfer of
the pig will not be a problem.

In shopping for a pig, you should be looking for a unit with two
high voltage bushings, no taps, 120/240 primary, and a secondary
voltage of 14,400 volts or higher. Remember! I am accustomed to
running pigs backwards! You will always see me refer to inputs
and outputs in reverse of utility practice when I talk about
pigs. Thus my "primary" is the actual secondary, and v.v..

The kVA rating on pigs are of course for continuous duty. They
will run 24-7 at the plate rating and not warm appreciably. You
may run them at twice the rated kVA output for 5 min or so
without any problem. 10 kVA seems to be a nice size for high
powered Tesla work. The 15 kVA pigs have a substantially larger
core, and require more energy to energize.

Since the cores on these are shell wound, you will not encounter
appreciable core saturation. These units must be run with a heavy
current limiter or they will pull the entire neighborhood into
your experiment. You should be able to energize them without
dimming the lights. Due the heavy current limiting required,
your input and output voltage will be lower than your line. My
10 kVA pig has a rated output of 23,890 volts, but with current
limiting, the calculated output is closer to 20,000 volts.

Both resistive and inductive current limiting may be used. The
inductive delay (about 1 sec.) in the current limiter and variacs
make control pretty jumpy, so it is best to use at least some
resistive ballast to smooth things out, especially if you are not
accustomed to these powers. The smoothest coils use all resistive
ballast, but things get pretty hot. The best combination seems to
be 6 or more paralleled oven elements placed in series with an
inductor. I opted for pure inductance because I hate to waste
energy as heat, but I feel the tug on my variacs through the
control wheel, and Gary has seen some arcing in the variac
brushes when the current limiter finally lets loose. When I add
some resistive ballast these problems are eliminated.
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-10-93 12:15
From: Richard Quick
To: Dave Halliday
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
-=> SEZ Dave Halliday to Richard Quick 'bout Tesla Video <=-

RQ> sections of my preliminary Magnifier work, which I encourage
RQ> others to follow up on. If you and your friends decide to
RQ> take on

DH> That was at the beginning - fascinating because I was
DH> completely un-aware that the other coil was involved - I
DH> just thought it was part of the background because I could
DH> not see any arcs coming from it.

DH> Very interesting that so much of the energy from it could be
DH> so closely coupled to the second coil... This will be a fun
DH> winter project!!!

The "extra coil" is completely uncoupled from the driver system.
Current from the driver is being fed into the base of the free
standing "extra" coil by transmission line. While you are not
able to see in the video... The transmission line glows with
corona from the heavy current.

DH> I was talking with one of the people and they agreed to
DH> start on a smaller coil - I was thinking in the order of 4"
DH> diameter and about 3' long.

The aspect ratio (height to width ratio) is important. The
planned coil has an aspect ratio of 9:1 (36" long, 4" diam.)
this should be reduced to no more than 5:1 on a 4" diam. coil.
6" coils work best with 4:1 aspect ratio, anything larger 3:1.

DH> The vacuum gap looked easy enough to build.

This gap underwent about two weeks of prototyping not shown in
the video, but once it was working, it worked great. It has
trouble at power levels over 5 kVA. After an evening on the big
coil at 8 to 10 kVA I had some pitting and melting of the
electrode faces. This was reduced as I cut back on the number of
electrodes, increased the size (both length and diam.) of the
electrodes, and allowed for a larger gap between electrodes.

DH> file about building a capacitor also looks pretty
DH> straightforward. I guess the main deal there is just to be
DH> patient and very careful. I have a vacuum pump so getting
DH> all the air bubbles out of it should be pretty
DH> straightforward.

These homemade capacitors are high Q, reliable, and relatively
easy to build. Pumping them down will really help.

> please feel free to fire of any questions to me. As
> you can tell, I have some little experience with all of these
> systems, and may be able to help.

DH> Questions???? Hoooo boy - stand back! <G*10E8>

DH> You talk a bit about the kind of plastic to use for form for
DH> the secondary coil. There is PVC and ABS available readily.
DH> You mention that PVC is better but you also say not to use
DH> Schedule 40 - both kinds of pipe are rated as being Schedule
DH> 40...

PVC is the worst plastic for use in secondary coils. It is
"lossy" (high RF dissipation factor) and has a low dielectric
strength. But it is commonly used because, as you mentioned, it
is available. Coil forms, regardless of material, should be as
thin as possible. Schedule 40 is thick, and is rated for pressure
use. Try to locate the thinner "drain" pipe or "flume duct" PVC
or other thin wall plastic. If PVC is used, it MUST be dry (baked
is preferred) and well sealed with a low loss sealant like poly-
urethane or two part epoxy.

DH> How about plexiglass...

Acrylic and plexiglas is pretty good. Dielectric strength could
be better, but the RF dissipation factor is much lower than PVC.
I have a couple of small acrylic secondaries and I have been
pleased with them. Plexi in large diam. tubes gets expensive.

DH> What determines a certain plastic being good? Should I look
DH> up the dielectric constants and select for a high number?

A combination of dielectric strength, and the RF dissipation
factor. PVC fails this test, and requires drying and sealing to
make it suitable. Teflon is the best; good dielectric strength,
and the lowest RF dissipation factor; then comes polyethylene,
polystyrene, and polypropylene, all of which are good. The same
standards are also used to judge capacitor dielectrics and for
general insulation in Tesla work, and the plastics rate in the
same order.

You asked about power supplies: The pole pig info is on it's way.
See my two part post on obtaining neons for free, and rebuilding
them for high output, high efficiency, Tesla power supplies.
Remember Tesla power supplies must be protected with extensive
RF choking, and safety gaps. This is especially important with
neons, which are much more delicate than pole pigs or potential
xfrmrs. I also use bypass capacitors. For bypass capacitance
across the power supply HV terminals you WANT a dielectric with a
high RF dissipation factor. Barium titanate capacitors with a DC
rating are ideal for this use. Use a 4x voltage safety factor.
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-10-93 22:16
From: Richard Quick
To: Dave Halliday
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
><Imported from Archives, 10/10/93 message to Dave Bearrow><

DB> How did you go about winding your coil? What are the specs?

The first step in winding a coil is to select a coil form. The
coil form should be a low loss material (we are talking RF
losses) like polyethylene, polystyrene, or polypropylene: but the
most common material is PVC plastic drain pipe (thinnest wall is
best) which is high loss. I used a section of PVC thin wall flume
duct.

Ratios of coil height to width are important. Small coils work
best with aspect ratios (height to width) around 5:1 - 4:1,
larger coils (over 8" diam.) have aspect ratios around 3:1. Now
we are talking about the actual winding length here, so allow an
extra inch or so of coil form on each end. Determine the length
required and cut the ends square.

The form must be sanded smooth of surface imperfections, dried
thoroughly, and if PVC is used, it must be sealed. A good sealer
is polyurethane, another is two part epoxy paint. By sealing the
surface of the PVC before you wind on wire you can negate the
excessive losses in PVC plastic coil forms. If necessary the coil
form may be sanded again after the sealer had dried.

The coil should be wound with good quality magnet wire. I use
double Formvar enamel coated magnet wire. Magnet wire gives you
maximum inductance. A coil should have over 900 turns, but not
too much over 1000 turns. There is a little leeway here. Select a
gauge of wire which will allow the aspect ratio and number of
turns to fall within this range.

I dug that up as it pretty much explains things, and you may have
missed the post.

DH> What determines a certain plastics being good?

As I omitted in the other message, the dielectric constant is not
the factor to go by when choosing a coil form. It is really
preferable to use a plastic with the lowest dielectric constant.
The reason for this is you want the distributed capacity of the
coil to be as low as possible. Capacitance in a coil stores
energy, and we want the throughput to be as rapid as possible.
The distributed capacitance in a coil retards the current peak
that follows the VSWR (resonate rise). Coils have enough problems
with distributed capacity from the length of wire, the closeness
of turns, and the number of windings. No need to make things
worse by choosing a plastic with a high dielectric constant.

What is most important in choosing a coil form material is the
dissipation factor. The dissipation factor of all commercial
plastics has been calculated, and somewhere in this mess I have
those figures. If my memory serves me correctly, the standard
RF dissipation factors are based on a frequency of 1 MHz, close
enough to judge if the plastic is suitable for coil work.

The next important factor to look at is the dielectric strength.
This should take second place to dissipation factors if your goal
is to build the most efficient coil possible. Proper con-
struction, more than anything, prevents electrical breakdown.

Even if the dissipation factor is very low (good efficiency) it
is best to use the thinnest wall coil form possible. Turns of
wire, coats of sealer, and hard plastic end caps will stiffen the
coil some. Low density polyethylene forms (such as wastebaskets)
give coils with very high "Q" factors (a measure of efficiency)
but are difficult to work with, as this plastic is VERY flexible.

As far as the electrical strength of a coil wound on a very thin
walled plastic tube, it should not break down internally if THE
WIRE IS NEVER ALLOWED INSIDE THE COIL FORM. Do not drill holes
or introduce the wire into the side of the coil. A hole anywhere
on the coil sidewall will cause a failure regardless of the di-
electric strength of the coil form plastic. My coils are capped
top and bottom with plexiglass plates that are approximately the
same thickness as the coil form wall. I use two-part epoxy cement
and I seal them airtight. It is OK to drill one small hole in the
bottom plexiglas plate to equalize air pressure, but I do not.

The air terminal capacitance is connected by lead wire (I just
use the magnet wire and avoid splicing) from the top of the coil.
The lead wire is "air wound" up to the terminal, with the turns
about the same diameter as the coil, or a little smaller. You
will see me doing this in the video when I set up for a low power
test in the garage.

The terminal capacitance must have a diameter greater than the
coil form, or spark will break out; either from the top of coil,
or from the air wound turns connecting the coil to the terminal.

The other construction secret not covered in the video is the
ground connection. Once the coil is wound and sealed I take the
base wire and pull it up out of the sealant until it is free all
the way to the beginning of the first turn. I clip off the excess
wire, leaving about a 2" tail. I lay the tail on a metal block,
and using a small ballpeen hammer, flatten it out as best I can.
A strip of copper sheet about 3/4" by 2" is then cut from stock
and bent slightly to match the curvature of the coil form. Solder
the flattened tail to the back of the copper strip. Position the
strip on the coil form just below the bottom turn of wire, and
scribe a rectangle through the sealant all the way to the coil
form plastic. Remove the sealer from the scribed area, then score
and clean the bared plastic. I then use epoxy to bed the copper
strip. This forms a high current grounding plate without
drilling. Ground wire or strap (preferred) can be held in firm
connection to the plate with tape or a large rubber band.
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-11-93 17:08
From: Richard Quick
To: Robert Taylor
Subj: Re: 10KVA TESLA COIL
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
-=> SEZ Robert Taylor to George Powell <=-

> using neon xformers..

GP> Do you have any probs with the xformers heating up after a
GP> while?

RT> To be honest--has been a while since I've had my xformers to
RT> play with. But as I remember, the Jacob's Ladder hook-up
RT> didn't cause any unusual overheat. You might check the size
RT> of your initiating gap at the bottom of the ladder. If it's
RT> too close--it will put extra strain on the xformer.

Nope, it will not make any difference. The gap at the bottom of
the rails can be closed and the xfrmr will not be subject to any
extra strain. If the rails are properly set, the gap will be
pretty close.

RT> One thought--if your xformer is in a small case, the
RT> overheat may be natural.

Even in a big case the heating is normal. A bigger case means it
takes longer for the heat to get to the point where you feel it.

RT> The ones that I used were fairly big monsters that weighed
RT> in at about 20 lbs. If yours is in a case about 5" high by
RT> about 10" long--then yours may be prone to overheating.

It's not "overheating", it's normal heating. Unless the tar is
melting, or output is diminished, there is no problem.

RT> However, if you have any questions as to your coil's
RT> integrity try using a VOM or continuity tester on both the
RT> secondary & primary & the case to make sure that there are
RT> no obvious shorts. A serious overheat can really test your
RT> fire insurance.

Doubtful, the secondaries can be shorted without any harm, and no
overheating will result. Shorts through the tar potting form
carbon tracks which are high in resistance and may not be
detectable with a VOM. And since these xfrmrs are magnetic
leakage shunted in the core, a short in a HV winding will basicly
cut the secondary out of the field flux generated by the primary.

The best way to test these suckers is to grab some HV rated wire
and draw an arc from each HV bushing to the case. If the arc
sputters, is weak, nonexistent, or intermittent then the core
should be unpotted and the winding replaced or restored. As I
mentioned in another post, about half the time unpotting alone
will cure a carbon track short.

RT> You might also want to hook your VOM up on the primary side
RT> & monitor your current draw (should be some specs on the
RT> case as to 120 VAC draw). If you see way-out draws or if
RT> the draw starts up w/time--then you may have a problem w/
RT> the windings.

If you go by this then every unit tested will show a problem
unless they were power factor corrected at the factory. The
plate specs give the OUTPUT wattage, output voltage, and output
current in miliamps. If you measure the input power vs. the
output specs you will find 50% of your input energy missing. The
unit gets hot....

You will lead Mr. Powell to believe there is a problem in the
core when that may not be the case. Due to the design of the core
this is completely normal. Fully one half of the input power is
converted to heat eventually, as energy is bypassed through
the core shunts to limit the output. Unless the xfrmr is getting
hot enough to melt the potting, or the output is markedly
diminished, there is no problem. If tar is melting, then the most
common problem is a shorted primary winding.

I have unpotted dozens of these transformers, and my experience
covers every major manufacturer. I have seen nearly every problem
that can cause failure, as I only rebuild failed units. I have
experimented with the effects of altering the core shunts for
greater output, and I have experimented with power factor
correcting in these units. I have done testing to measure the
efficiencies, and have developed procedures to improve these
efficiencies. In other words I know these cores backwards and
forwards.

Mr. Powell may not have much experience with magnetic leakage
controlled xfrmrs. He is most likely interpreting the normal
heat production as a problem. A normal step up xfrmr weighing
10 lbs, with a throughput under a kilowatt, would not get warm.
The normal step up xfrmr is not shunted, and wastes very little
energy. Yet the neon gets quite warm with throughputs of only a
third of a kilowatt. The neon is a different breed, and produces
as much heat as output.

I hope I have set the record straight. If you doubt my analysis,
please unpott a neon core, and look at the physical placement of
the shunts. You will wonder how any magnetic flux at all can get
to the secondary windings. The shunts are positioned so as to
place a direct magnetic bypass that completely surrounds the
primary. It is in effect, a built in magnetic short circuit. The
field flux passed through these shunts is wasted energy, and the
wasted energy heats the iron core. If you have a 360 watt neon
core, no power factor correction, and no core modifications, you
will get about 360 watts of heat if you put a Jacob' Ladder or
Tesla coil on it. 360 watts of heat will bring the core temp up
quickly and it will stay quite warm to the touch. Yet everything
is working fine, except for your efficiencies.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-12-93 14:56
From: Richard Quick
To: Dave Halliday
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
-=> SEZ Dave Halliday to Richard Quick <=-

DH> Hi Richard - again, thanks for the fantastic video!

RQ> Larry J. Rebman
> The Transformer Bank, Inc.
> University Technology Center
> 1313 Fifth St. SE
> Minneapolis, MN 55415

RQ> Tel: (612) 379-3958, Fax: (612) 379-5962

DH> GREAT!!!!!

>The retail cost is a little over $1.00 a pound, so figure a 230
>pound, 10 KVA xfrmr, will run about $250.00.

RQ>The Transformer Bank has a shipping contract with
RQ>Consolidated Frieghtways

RQ>My pole pig ran $303.00, including shipping, and was
>delivered to me ten days from the date I dropped the
>certified check in the mail.

Your shipping rate may be higher since you are all the way cross
country, and your delivery time will most likely take longer.
Still, where else are you going to go?

RQ>The unit came with certification papers that match the serial
>number on the plate, showing it to be PCB free.

DH> This is exactly the info I have been looking for!

Having been there I pretty much know the score. I looked for over
a year for a supplier for these units, while the utilities
educated me on the EPA requirements. Do not accept a pig, even a
free one, if it does not have PCB certification papers. Some pigs
I have seen will carry a PCB free cert. number on the plate, and
that too is OK. You can then write the manufacturer and they will
mail the papers if you provide them with the number.

It is not the PCBs that bother me. The problem occurs if you want
to sell or dispose of the unit. With current regulations, and
lack of certification, you have a legal hot potato that can cause
you problems. I have not seen the letter of the law, but the
utilities have informed me the legal implications are rather
severe, and place serious liabilities on the owners of pigs
containing PCB.

There are a few transfer yards that have clean room holding
facilities. They are expensive to own, maintain, and operate,
but they are licensed to drain the old oil, rinse the cores, and
scrap them. Cores can be purchased for a few bucks ($5-$20).
The problem is that the cores are old, frequently damaged, or
contaminated with water (from sitting in the rain) and won't hold
up unless they are dried, repaired, and resubmerged in xfrmr oil.
Better off to pay a little more and buy a surplus new unit.

Another type of xfrmr excellent for coil work is the potential
type xfrmr. These are potted in plastic, not tar, and are not
shunted like neons. They carry the HV ratings required, and/or
can be placed in series (two 7500 volt units for a total of
15KV). Since the cores are NOT shell wound, they will saturate,
and so they are safer and require little or no current limiting.
These xfrmrs may be obtained from utilities without the problem
of EPA regs. The normal ratings on potential xfrmrs runs from
about 1-3 KVA, and so are ideal for the middle area between neons
and pole pigs. The surplus cost on these runs from $25.00 -
$50.00 each, but they will be used, not new, surplus.

These xfrmrs are used to step down a kilowatt or two for cooling
fans, and for line voltage sensors in substations; so they are
not manufactured in the quantities that pigs are. They are much
harder to find in the surplus market, but definitely worth
grabbing if you come across one. If you developed any contacts at
the local utilities while searching for a pig, you might call
them back and ask them about potential transformers.

DH> I also got your postings on neon sign transformers yesterday
DH> - the idea of getting the reject units from a sign company
DH> is obvious - should have thought of that one... <WHACK!>
DH> ( sound of head hitting desk )

Yeah, neons are not built very solid. The secondaries are
el'cheapo, as the thinnest wire possible is used. The failure
rate is pretty high even in their rated service. Since the copper
content is low, they are not commonly recycled, and the cores
pile up quickly. The higher the output current rating, the better
they are built. Once the tar potting is removed, they last much
longer in Tesla use. Tar is a very poor RF insulator. To a Tesla
discharge, the tar looks more like an impedance! Pick up dead
units for nothing, remove the tar, modify the core slightly, and
use pfc capacitance; then they will serve cheaply and effi-
ciently. You must use heavy RF choking, safety gaps, and bypass
capacitors if you want more than a few hours of heavy duty
service from a bank of neons.

As far as RF choking is concerned, the HV filter board I designed
and built in the video is the best I have ever used. I have not
had a single xfrmr failure since I built it. Bypass capacitors on
neon power supplies must be center tap grounded, so I switch
to using a different capacitor setup. As the secondaries on neons
are center tap ground, so must the bypass capacitors. I use two
stacks of caps; each stack has a connection to a HV bushing, and
to the system ground.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-13-93 13:26
From: Richard Quick
To: Brian Mcmurry
Subj: Re: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
BM> On Sun 7-Nov-1993 4:14p, Richard Quick wrote:

RQ> These units must be run with a heavy current limiter or they
RQ> will pull the entire neighborhood into your experiment. You
RQ> should be able to energize them without dimming the lights.

BM> I've been following all the Tesla threads and wonder what
BM> your monthly electric bill runs. :)

BM> BTW, keep it coming.

Thanks, another vote of confidence. Much appreciated.

Well it's not as bad as it sounds. Tesla had one god: EFFICIENCY!

If you follow his work, you will find that efficiency is what
makes his systems beautiful, they don't waste much.

At one time I hooked a standard electric company wattmeter up to
the 240 V 100 A single phase supply circuit that I am using at
this time. Over a period of a month or so I used about $20.00
worth of electricity to actually fire coils.

There are other circuits that I tap to provide utilities to the
coils. Some of my spark gaps use compressed air to quench, others
use 240 volt vacuum motors, yet another uses muffin fans, I also
run a rotary gap motor in combination with a static gap on all my
bigger stuff for better efficiency and performance. These
utilities might use 25% of the energy I put into the coil, so add
another $5.00. I would feel comfortable saying $25-$30 a month.

Even when I run a big coil at 8-10 KVA I don't leave it running
all night. Five or six runs of between 3-8 minutes each is enough
to satisfy me, give me the data I need to improve, and get some
good video.

I don't fire every night. It is much more fun to have company
over and have a friend video tape the coils in action. The big
stuff has to be fired outdoors since I don't have the ceiling
height or floor space to fire anything bigger than an 8" coil
indoors. Outdoor firing is weather and neighbor dependant. I have
had some bad luck firing coils in windy conditions, and the
neighbors have threaten to get their torches and burn me out
if I fire too late at night (spark gaps sound like unmuffled
chainsaws at this power level).

The pole pigs used in heavy work are over 95% efficient, but
current limiting, depending on type, can waste 50% of your input
energy in the form of heat. In every area of my work I have
pushed the edges of my efficiencies, just as Tesla would have.
I use efficient step up power supplies to drive the oscillators,
with efficient: current limiters, tank circuits, capacitors,
spark gaps, etc.. With neons power factor correction helps a lot.

The goal in 1/4 wave coils is to turn every watt possible into
discharge, and waste as little as possible between the wall and
the discharge terminal. I am very good at it, and I believe I am
holding record spark lengths for input powers. If I do not hold
records, then I am very very close, but I have not seen any
system outperform mine up to 10KVA. And there is still room to do
better with my 1/4 wave coils.

To give you an idea, my power processing efficiencies range from
460 to 1100 watts (power drawn from the wall), per foot of spark
generated on my large coil. These figures are not linear, as I am
not using a synchronous rotary spark gap. The average strike from
the coil will reach anywhere from nine to eleven feet at 5-8 KVA.
But have seen more than a few 15' strikes at powers under 10 KVA.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 13 Nov 93 19:17:00
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Tesla "Q" Factors

Since some people are saving these posts to disk, and at least
one other person (Dave Halliday) is going to embark on some coil
building. I thought I would take a moment and discuss some Tesla
theory that directly relates to coil efficiencies. The subject
is the "Q" factor.

Q is literally the "Quality" factor. There is no real way to
calculate Q in a subassembly, assembly, connection, or component
in a Tesla coil. But Q exists. Q in a secondary coil can be calc-
ulated from the physical coil data after it is wound, but with
most coil parts it is more like a "god". Some people dedicate
their lives in search of god, coilers dedicate their lives in
search of higher Qs.

The Q factor of any Tesla component is a combination of material,
design, and construction. A coiler never reaches near theoretical
Q factors. We don't wind our coils out of high temperature super-
conductors and fire them submerged in liquid nitrogen. Indeed
people hardly ever submerge their coils in oil like in good old
days. Oil submersion is probably the single greatest thing you
can do to raise the overall Q factor in any Tesla coil system. In
the old days they almost had to submerge the coils in oil to
regain Q that was lost in the use of "classic" materials such as
wood or cardboard coil forms, rubber or tar insulators, silk or
cotton covered wire. These "classic" construction materials are
inherently low Q and result in designs and construction techni-
ques that are also low Q. Builders tolerated oil leaking wooden
boxes and greasy cabinets in many cases to get a good spark.

We live in an age of high Q materials and construction techni-
ques. I have mentioned some of the most commonly used materials
in several posts, but I will list a few again. Teflon, polyethy-
lene, polystyrene, polypropylene, acrylics, epoxy, hot glue,
enamel and polyurethane sealers. As well as the all time classic
high Q corona suppressant, mineral oil.

Modern coils had to be redesigned in order to take advantage of
these new materials. These modern designs differ in many ways
from a coil using "classic" low Q materials. Secondary coils can
be close wound with magnet wire rather than space wound with
insulated wire. Primary coils can be tighter, placing higher
inductance into a smaller area. Coupling can be increased
dramatically, even in 1/4 wave systems, by using corona sup-
pressing sealers and toroid discharge terminals. The coils get
smaller, more powerful, and more efficient.

Building high Q systems means we can live without things like oil
submersion, and still get better spark. With these higher Q
systems it is more economical to put additional capacitance and
heavier power supplies on line to increase spark than it is to
struggle getting the system Q closer to ultimate theoretical.
Theoretical Q can go to infinity.

So when you are designing, hunting materials, and building;
always keep an eye on the Q factor. Attention paid to many little
areas adds up to substantially higher overall system Q. A solid
ground, tight clean connections, close wound and sealed
secondary, primary coil of high Q material wound on a high Q
plastic form, well aligned gaps that quench, plastic film HV
pulse discharging capacitance, and toroid dischargers are some of
the major factors in the overall system Q.

Experiments in a variety of Tesla systems shows that the overall
Q of the system is limited by the lowest Q component used. The
old expression "The chain is as strong as its' weakest link"
applies.

One area that is frequently neglected by Tesla coilers is the Q
of the system RF ground and the ground path. Since coil systems
are built from the "ground" up, this is the first thing a good
coiler will look at when he goes to set up and fire a coil. I
know a guy in New York who fires at about the same power levels
as I do. My coil systems are much higher Q and I get much better
spark using less energy with a smaller coil. When I took a close
look at his coil setup, I noticed he was grounding his coil
system to the neutral wire in the breaker box. Walking outside, I
traced the ground path to a single 3' copper plated rod driven in
by the utility company to ground the supply xfrmr to the
building. This is completely inadequate for high powered Tesla
work, and is quite unsafe.

I also noticed that this guy had a newly constructed all wood
power control cabinet. Now there is nothing wrong with that as
long as it is well wired with ground strap, which it wasn't. But
out back I could see a nice metal control cabinet that had been
recently gutted. When I inquired, he stated he had to switch to
an ungrounded, wooden, control cabinet because he was drawing
sparks to fingers when he touched the controls...

The paced distance from the base of his secondary to the 3'
copper clad ground rod was slightly over 75'. Most of the
distance was traversed with #10 wire. No wonder when he grounded
the cabinet and touched to controls he drew spark, his ground
path had a high RF impedance, and was backing up like a clogged
toilet. I tactfully offered some advice, which was refused.
Obviously he had spent a lot of effort compounding his mistakes,
and had no desire to let someone else point them out.

Don't make the same mistake. Be efficient and safe. Ground
properly from the very start. Think Q!

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-13-93 00:42
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Looking over my last post, I can anticipate a few questions.
I described a very poor grounding system. What then makes a
good RF ground?

Well a small coil can fire off a radiating counterpoise (insul-
ated metal plate) a few feet square. But when you overload a
counterpoise, you get a really wicked corona display, and the
coil will produce no additional spark. Having set up various
experiments to study this effect, including tracing the ground
current, and using a current transformer to measure the RMS amps
coming from the base of a Tesla secondary, I can tell you this.

There is no such thing as a RF "system" ground that is too heavy.

Not in Tesla coils!

This is another thing that Tesla went on and on about. But my
follow up experiments in this area, which have been quite
extensive, show that he knew what he was talking about.

I got extremely lucky in that we have a hydraulic car lift in our
back driveway. There is a 5' steel cylinder that is 14" in diam..
In addition to the giant piston, there are buried oil and air
tanks with all of the associated plumbing. The lift controls are
sunk right where the house foundation drains, and it is in the
lowest spot in rear of the house. There are no electrical
connections made to this lift, air being supplied when needed by
a hose. This is my Tesla ground.

A good Tesla RF ground is usually developed, not happened upon.
It will require some digging and post driving. It needs to be
kept moist. Drive deep with copper pipe, or copper clad rod, and
keep adding to it. Metal culverts, metal sewer drain pipe should
be connected if available. Spread out! Do not drive rod or pipe
close together. Four or five 8' rods driven in a long row, 8'
apart will work. A ground that you are absolutely sure will
ground a bolt of natural lightning, will be heavy enough to
ground most coils. DON'T CHINCH!

People have asked me if I get complaints about RFI. The answer is
no. The reason is that I isolate my coil (system) ground from the
copper water pipe and from the utility ground (which in my house
are the same). Here is a basic list of things that you DO NOT
CONNECT to the system RF ground: WATER PIPE, GAS PIPE, UTILITY
GROUND, ANYTHING THAT STICKS UP IN THE AIR (fences, gutters,
downspouts) TELEPHONE GROUNDS, & CABLE GROUNDS. Most anything
else is fair game, but use common sense.

You build or find a heavy ground and you ground your coil system
to it. The connections made to this RF ground are as follows:
SECONDARY COIL, SAFETY GAP, STEP UP XFRMR CORE, BYPASS CAPACITORS
(if using a center tap grnd xfrmr), SPARK GAP MOTOR HOUSINGS,
SPARK SHIELDS, AND ANY OBJECT SUBJECT TO BE STRUCK WITH DISCHARGE

I don't usually use my caps lock, but this is important. This
technique prevents RFI complaints, and will save valuable
electronic equipment in your area from destruction. It may save
you from the last shock of your life.

You ground your variac housing to your neutral wire. All other
coil controls, relay housings, control xfrmr cores, line RFI
filters (run backwards) are grounded to the variac housing. Strap
is taken from the variac housing to a well grounded water pipe.
This protects the coil operator and the control circuits from
kickback that may come down the line from the step up xfrmr.

Two 60 cycle cables are run from the variac, through reversed
line filters, out to the step up xfrmr. No ground connection is
made anywhere between the 60 cycle cabinet ground and the RF
system ground. Hot wires only are given to the primary of the
step up xfrmr, as well as any gap motors or other utility for the
coil tank circuit.

This is called the "two ground system" and it is highly recom-
mended. The idea of the two ground system is to send all of the
RF to a dedicated ground, and prevent bleedover into your house
wiring, control cabinet and/or water pipe. It also protects the
operator with two low potential grounds from the lethal possi-
bilities of a coil misfire or similar "incident".

People have told me I am crazy for messing with all of this HV.
I take NO CHANCES with my ground. The ground strap is literally
the "bottom line" in coil safety or any other HV apparatus. If an
accident occurs; a core shorts out, a capacitor blows, or the
secondary decides to dump a 10' spark back to the tank circuit;
I know my safety gap - RF ground will handle the load. My 60
cycle cabinet ground is my backup. With tank circuit energies in
the megawatt range you can't afford to have a weak point.

Keep the physical distance between the base of the secondary coil
and the system RF ground as short as possible. I try never to go
further than 20 feet for low power stuff, and 15' or less for the
high powered work. Use the heaviest strap possible. I run two
heavy straps; one from the base of the secondary directly to
system ground, the second snakes around and grounds everything
else. This is a high Q Tesla grounding system. It gives the best
coil performance, the most safety for the coil operator,
and guess what?

People in my house, and the neighbors next door, can watch TV or
listen to the radio, with no snow or static! Even during high
power operation! I never get spark from my coil controls. All of
the RF currents that are not expended in spark are directly,
positively, grounded through a high Q ground path to a high Q
ground that is electrically isolated from all other equipment.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-13-93 15:17
From: Dave Halliday
To: Richard Quick
Subj: Tesla coils
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Hi Richard - I have had time to go through and read the stuff you
posted - thanks again for the time you are spending here - this
info will be not only a great help but also a great motivator.

I had thought about getting back into Tesla coils for some time
and it took seeing what some one else out there was doing it to
get me started <grin>

DH> Very interesting that so much of the energy from it could be
DH> so closely coupled to the second coil... This will be a fun
DH> winter project!!!

I figured that it was not part of the primary / secondary circuit
but got it's power through the wire off of the Tesla secondary.

Amazing stuff and definitely the next thing to try after building
the first coil.

DH> I was talking with one of the people and they agreed to
DH> start on a smaller coil - I was thinking in the order of 4"
DH> diameter and about 3' long.

******(cut from another part of a post)*******
The coil should be wound with good quality magnet wire. I use
double Formvar enamel coated magnet wire. Magnet wire gives you
maximum inductance. A coil should have over 900 turns, but not
too much over 1000 turns. There is a little leeway here. Select a
gauge of wire which will allow the aspect ratio and number of
turns to fall within this range.
**********************************************

OK - I made an "editorial decision" today to go for a 6" diameter
form and make it 24" long. I just was out running errands and
got 1,500' of 22 gauge Heavy Formvar insulated magnet wire so
with a diameter of 0.0253, this works out to 948 turns - right
in the ballpark that you suggested in another part of this post.

I think the other people were thinking in the realm of the normal
misconception of Tesla coils as being long and skinny but I guess
that would make them longer than 1/4 wave...

We'll see what happens!

Vacuum Spark Gap...the video, but once it was working, it worked
great. It has trouble at power levels over 5 kVA. After an
evening on the big coil at 8 to 10 kVA I had some pitting and
melting of the electrode faces. This was reduced as I cut back on
the number of electrodes, increased the size (both length and
diam.) of the electrodes, and allowed for a larger gap between
electrodes.

OK - I wonder if it would be feasible to make it with
continuously variable gap size - something with threaded plastic
rods...

I think that since we are starting with neon sign x-formers, we
can just use the standard 6" PVC gap you showed - aren't going to
be running too much power through it <yet>

These homemade capacitors are high Q, reliable, and relatively
easy to build. Pumping them down will really help.

As I said - I do printing as well as the electronics and
computers and every piece of equipment here ( almost ) has some
kind of vacuum pump associated with it. These are all
rotary-vane types so not really high Torr but should be OK for
"potting" the caps in oil.

DH> You mention that PVC is better but you also say not to use
DH> Schedule 40 - both kinds of pipe are rated as being Schedule

OK - there is some pretty thin wall stuff in our local "Home
Center" store - I was worried about mechanical strength though -
I can deflect... (Continued to next message)

this pipe with just moderate pressure - I will have to stop into
the Cadillac Plastics store and see what they have in their
cut-off's bin... Also, I have a small South Bend lathe and could
probably get Schedule 40 and then turn off a bunch of it until it
got too thin...

Baking it and then sealing it is a good idea - I will probably
use the slow speed on the lathe to wind the coil so I could also
turn it slowly while I was applying the sealer - keep it drip-
free...

When I was getting the wire, I made the mistake of pricing Teflon
insulated wire. That would be a coil that shocks people twice.

You spent ??HOW?? much... <grin>

You asked about power supplies: The pole pig info is on it's way.
See my two part post on obtaining neons for free, and rebuilding
them for high output, high efficiency, Tesla power supplies.

I got both sets of info - the guy you recommended was out hunting
but will be back on this Monday - they knew about Tesla coils
though and recognized your name...

Remember Tesla power supplies must be protected with extensive
RF choking, and safety gaps. This is especially important with
neons, which are much more delicate than pole pigs or potential
xfrmrs. I also use bypass capacitors. For bypass capacitance
across the power supply HV terminals you WANT a dielectric with a
high RF dissipation factor. Barium titanate capacitors with a DC
rating are ideal for this use. Use a 4x voltage safety factor.

Got it - the insulation of the neon is only meant to handle 15
KV, not whatever the coil is putting out... I have a bunch of
largish ferrite toroids so I'll use them and a spark gap.

Great idea - high current, low impedance and quick connection.

Anyway, this message is kind of chopped up, I saved your posts
and then just went in with Q Edit and edited and added replies
but you should follow who is talking...

Again - thanks for your time and info - I'll have to send you
copies of the pictures once we start building this puppy!
301-794-6496 (1:109/546)

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 15 Nov 93 22:51:20
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Spark Gap Technology

I recently explained the definition of "Q", and the requirements
and functions of high Q grounding systems in Tesla coils. Another
area that needs attention is spark gap technologies.

Spark gaps are the "brain" of the Tesla Coil. They are high the
voltage switches that allow the tank circuit capacitance to
charge and discharge. As performance of the spark gap switch is
improved, peak powers in the tank circuit grow without requiring
additional input power. When a good coiler sets up and fires a
system, the first thing he looks at is his ground. The second
thing he looks at is his spark gap system.

Before I cover the main points on spark gaps, I want to talk for
a moment about their more modern replacements, the vacuum tube,
and the solid state transistor (FET etc.). Both modern day
replacements can be made to function in Tesla type oscillators
in several modes. A single resonating coil may be base fed RF
current from solid state and tube drivers, or primary coils may
be driven with amplifier circuits. Class C amplifiers are
preferred. Both of these modes work well within the power
handling abilities of the switch (tube or solid state device),
but when it comes to handling raw power, nothing delivers the
megawatts like the old fashion spark gap. The spark gap gives
the biggest bang for the buck.

No discussion of spark gaps is complete without at least a rough
definition of "quenching". This term is commonly thrown around
when talking about spark gaps. When I began coiling, I saw the
term frequently, but never could find a good definition.

Quenching refers, more than anything else, to the art of extin-
guishing an established arc in the gap. The term points to the
fact that it is much easier to start a gap firing than it is to
put one out. In Tesla coils, putting out the arc is imperative to
good tank circuit performance.

A cold, non-firing, spark gap is "clean". It contains no plasma,
or hot ions. On applying voltage to the gap, a tension is esta-
blished, and electromagnetic lines of force form. The physical
shape of the electrodes determines to a large degree the shape of
the field, or lines of force, and the resultant breakdown voltage
of the gap at any given distance. In other words, electrodes of
different shapes will break down at different voltages, even with
identical distances between them.

Once the voltage punctures the air (or other dielectric gas)
the gap resistance drops. The breakdown ionizes the gas between
electrodes, and the arc begins to ablate and ionize the metal
electrodes themselves. This mixture of ions forms a highly cond-
uctive plasma between the gap electrodes. Without this highly
conductive channel through the gap, efficient tank circuit
oscillation would be impossible. But the plasma also shorts the
gap out. A gap choked with hot ions does not want to open and
allow the capacitors to recharge for the next pulse. The gap is
gets "dirty" with hot ionized gases, and must be quenched.

Quenching typically relies on one or more techniques. The most
common method used is expending the arc out over a series of
gaps. Gaps of this type are know as "series static gaps".
"Static" in this use refers to the fact that the gap is not
actively quenched. The plasma is formed in several locations,
and the voltage at each gap is lowered as more electrodes are
placed in series. Heat, hot ions, and voltage are distributed. As
the tank circuit loses energy to the secondary coil, the voltage
and current in the tank circuit, and likewise across the series
of gaps, drops to the point where the arc is no longer self
sustaining. The arc breaks, and the capacitors are allowed to
recharge for the next pulse.

The second type of quenching technique involves using an air
blast. A high speed air stream is introduced into one or more
gaps. The air stream does not alter the magnetic lines of force
that cause a dielectric breakdown in the gap, so gap distance
remains unchanged. But once an arc is established, the air stream
removes hot ions from between electrodes and physically disrupts
the established arc. The gap is swept clean of hot ions, the arc
breaks, and the capacitors are allowed to recharge.

A third type of quenching used is the magnetically quenched gap.
A strong magnetic field is placed between the electrodes. Since
this field alters the field formed by the high voltage prior to
breakdown of the dielectric in the gap, it may affect the break-
down voltage of a given set of electrodes. Once the gap breaks
down however, the field shape changes. The high current flowing
through the gap generates a field shape associated with the
current. By placing a strong magnetic field in right angles to
the current flow, the arc is disrupted. This disruption tears at
the magnetic lines of force formed by the high current channel
flowing through the gap. The arc is twisted, and broken, without
having to remove ions.

Another type of spark gap called the "quench gap" is used on
coils designed for CW output. This gap was discussed in a
previous post and will not be covered here.

The next stage employed in spark gap technologies is placing a
rotary gap in the circuit. The rotary gap is a mechanical spark
gap usually consisting of revolving disk with electrodes mounted
on the rim. The rotor is spun and the electrodes move in relation
to a set of stationary electrodes nearby. As a moving electrode
comes near a stationary electrode, the gap fires. As is moves
away the arc is stretched and broken. The rotary gap offers the
sophisticated coiler the opportunity to control the pulse in the
tank circuit. A properly designed rotary gap can control the
break rate (bps) and the dwell time.
(continued in next post)
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 15 Nov 93 22:57:11
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
(cont.)
Rotary gaps are run in two modes, synchronous and asynchronous.
A synchronous gap runs at a fixed speed and is constructed so
that the gap fires in direct relation to the 60 cycle waveform of
the line feed to the capacitors. The point in the waveform where
the gaps are closest can be changed by rotating the synchronous
motor housing or by altering the disk position on the motor
shaft. By carefully matching the output of the supply transformer
to the value of capacitance in the tank circuit, then running
a properly set up synchronous gap, it is possible to have the gap
fire only at the voltage peaks of the 60 cycle input current.

This technique allows the tank circuit to fire only on the
maximum voltage peaks and delivers the pulse from a fully charged
capacitor each time the gap fires. If properly engineered,
synchronous spark gap systems will deliver the largest EMFs to
the secondary coil. They are however, the most finicky, and
difficult to engineer of any spark gap, and require sophisticated
test equipment to set up.

Asynchronous gaps are more common. They work quite well and are
much easier to run. Fixed or variable speed motors may be used,
though variable speed gaps give the builder the most experimental
leeway. Break rates need to be in excess of 400 bps, and I have
found that breaks rates around 450-480 bps give the best
discharge. Since the gap is firing more often than the 60 cycle
waveform switches polarity, more power can be fed into the tank
circuit, as the capacitors can be charged and discharged more
rapidly. Though this system will increase the amount of spark
from the secondary, sparks are generally not as long as with
synchronous gaps.

At higher powers (over 5 kVA) even a rotary gap will not deliver
the quench times required for excellent performance unless it is
very large. If the arc in the spark gap hangs too long (NOT
quenched), it leaves the tank circuit electrically closed. With
the gap still firing energy will backflow from the secondary into
the primary and create continued oscillation in the tank circuit.
The secondary is then supplying energy to maintain the arc in the
spark gap. As power levels build, so does the pressure on the
spark gap. Engineering more sophisticated gap systems is the only
solution in large 1/4 wave coils and Magnifiers.

The easiest solution at 5 kVA is to add a static gap in series
with the rotary. By messing with the gap settings it is not
difficult to develop a gap system that fires smoothly and
quenches well. As power levels increase though static gaps will
be overwhelmed. More sophisticated gaps are required to replace
the static series gaps. Magnetic or airblast gaps must be used in
conjunction with the rotary gap to remove the strain on the
rotary and get the quench times back down.

Somewhere in here I need to cover the Q of spark gaps. Not all
spark gaps have the same Q. I have found that using large series
static gaps with lots of electrodes; the Q of the gap system
decreases as the quench time decreases! Try to avoid static gap
designs with more than 6 - 8 electrodes in series.

As my power levels went up, and my spark gap Qs went down, I
experimented with options to regain performance. I found that by
running static gaps in a combination of series/parallel gave me
good quench times and I regained some lost Q from the arc having
to make so many series jumps. The idea was to split the arc down
into two or three equal paths, reducing the current traveling
each set of series gaps. In this fashion I was able to achieve
excellent quench times with a small rotary running around 5 kVA.

The lesson learned was too many gaps in series kills the Q of a
spark gap. By adding gaps in parallel, and reducing the number of
gaps in series, some Q was regained while power levels increased.
This is a valuable hint in spark gap designs.

Another factor that should be brought into this discussion is the
effects of cooling the electrodes. To start with, I have never
run even a simple static gap without some airflow. My first few
really good static gaps were constructed inside of PVC pipe
sections with a 5" muffin fan on top. The fan did not supply
sufficient air to disrupt the arc, but did assist in removing hot
ions, and cooling the electrodes down. This allows for longer run
times. As my work progressed I realized that reducing the
electrode temperature, while not actually quenching the gap,
reduces the amount of metal ions introduced into the arc, and
makes the gap easier to quench with an airblast or magnets.

I am going to cut this off here. I feel I have covered most of
the basics, and thrown a few ideas out into the cyberspace. I
would be more than happy to expand on spark gap technologies at
any time should somebody have any specific questions, comments,
problems, or corrections. Remember, armchair debate is no
substitute for actually going out an experimenting with a few
live systems, and I am always hoping someone will tell me a
better way to do it!

One final safety note. Spark gaps are loud, and emit a lot
of hard UV radiation. Wear hearing protection as required, and
never stare at an operating spark gap without welding goggles.
To examine the arc on large coils, a sun observation filter
on a small telescope will tell you if your gaps are quenching.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 16 Nov 93 20:33:44
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Well, lets see; I covered basic spark gaps yesterday, next on
the list would have to be pulse capacitance. I posted a two part
message last month sometime detailing construction of a rolled
type pulse discharge capacitor. Since the detail of this partic-
ular unit was pretty well covered, I will focus on other homemade
types; the flat stacked plate type capacitor, a little on the
salt water cap, and a little on capacitor theory as it applies to
Tesla coils.

I have seen several types of homemade stacked plate capacitors.
The two types differ as to the orientation of the plate stacks.
Some are stacked vertically, others are stacked horizontally.
Before I go into construction details I should cover some of the
advantages of flat stacked plate caps for use in Tesla coils and
other high voltage applications.

Flat plate caps have no inductance. Rolled caps contain two or
more plates which are tightly rolled up. Rolled plates exhibit
some properties of coils, they contain a certain degree of self
inductance. This limits the size of the rolled cap in Tesla
applications. As plates grow in size, the self inductance grows,
and the caps exhibit self-resonance that will interfere destruct-
ively with the oscillation of the Tesla tank circuit. The rolled
cap that I posted about previously, is about as large as you can
get in a single unit without having self-resonance drop below 1
megahertz.

Flat plate caps are better adapted for pulse applications. Rolled
caps have to discharge a long plate. The further away the free
end of the plate is from the high current terminal, the longer it
takes for the cap to discharge. In essence this distance is also
an extension of the tank circuit wiring, as the plate gets longer
losses increase. Again the rolled capacitor I posted previously
is pushing the design limits of efficiency in this area. As the
rolled cap gets larger, efficiency of pulsing drops off.

Flat plate caps can be constructed to handle higher voltages.
Rolled caps have efficiency limits in individual units as to the
breakdown voltage. A single dielectric is used per plate. If
dielectrics are made thicker, efficiency drops off, if made
thinner efficiency increases, but they break down. Using standard
materials, the rolled cap I posted about is at the edge of this
design limit as well.

Flat plate caps can be built for larger capacitance. The rolled
cap, because of the design constraints listed above, won't give
you much additional capacitance without increases in losses,
problems with self-resonance, and lowering of the capacitor Q.

The rolled cap that I posted is a good unit. I have built nearly
20 of these caps, and I use them a lot. But do not look to expand
much on this design. It has passed through several improvements
and I really think it is pushing the design limits in all of the
important areas. Next we need to look at the flat plate cap, as
there is much to be done yet, but first look at the dielectric.

The best Tesla capacitor dielectric is low density polyethylene
plastic. Whether you build rolled, stacked plate, or salt water
caps you should look hard at this plastic before settling on
anything else. It has an extraordinarily low RF dissipation
factor for the cost. The actual "in use" dielectric constant on
homemade caps using this plastic is right around 2. This is a
little lower than the book value, but homemade applications of
this dielectric rarely have the close plate bonding that are
achieved commercially with clean room vacuum presses.

This dielectric melts at 100 deg. C. But because of the very low
dissipation factor the plastic is subject to very little in-
ductive heating. There is little loss, therefore little heating.
When using this plastic however, it is imperative to cover in
mineral oil to distribute any heat that is formed, suppress
corona and displace air. Plastic caps not covered in oil are
guaranteed to fail in seconds. Plates, dielectric, and oil MUST
BE CLEAN!... BTW The cheapest and most common plate material is
aluminum. In the rolled cap, aluminum flashing is available
precut in a perfect plate width, and there are other widths
available. Flat plate caps can use flashing, but it is frequently
more cost effective to use foil.

Now that we have established a few basics, lets talk plate cap
design. The first type of flat stacked plate requires the cap be
pumped down to a pretty hard vacuum to remove air. This is the
horizontal stacked plate capacitor. Typically these are built in
a Tupperware type storage box. Plastic, plate, plastic, plate
etc. are stacked one atop the other to build up the value. The
breakdown voltage is directly related to the dielectric thick-
ness used. 60 mil poly sheet is recommended and will have a
breakdown voltage in the Tesla tank circuit between 11-17 kv
rms input voltage depending on the quality of material, and the
cleanliness of the construction.

Once the box is filled, and all parallel plate connections are
made, high current busses are brought through the lid of the
container and sealed airtight with hot glue. Then the lid is
snapped on, and it too is sealed with a bead of hot glue around
the edges. The next part is important: A single hole is made in
the lid for the vacuum connection. A fitting is hot glued into
the hole and a hose is attached to the vacuum pump. The cap is
pumped down, then the hose is clamped off and disconnected with-
out allowing air back into the cap. Submerge the hose in a bucket
of clean mineral oil and release the clamp. This allows the oil
to backfill the capacitor, and displaces the air that was
removed. Once backfilled to normal pressure, I pump them down a
second time, and repeat the procedure to make sure that all
trapped air between the plates is removed. Air bubbles will form
corona hot spots that will cause dielectric failure.

The vertical stacked plate capacitor is much like the cap I just
covered. But the vertical cap does not require pumpdown. A tank
is used to hold the vertically stacked plates and dielectrics.
The unit I examined was built in a glass fish tank that employed
no metal in construction. Foam padding was laid in the bottom of
the tank, and wedged in around the sides of the vertical
capacitor stack to cushion it and wedge it in place. The foam
padding also reduced the mineral oil required to cover the stack.
The reason these caps do not require pumpdown is that eventually
the oil will displace the air trapped in the unit. A break in
period of low voltage operation assists the removal of trapped
air, as the pulsing of the cap vibrates the plates and agitates
the air bubbles. The disadvantage of the unit I examined was the
glass fish tank. I have seen plastic waste cans that could be cut
down for use as a tank in this construction.
(continued next post)
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 16 Nov 93 21:48:37
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
(cont from previous post)

Higher Qs, higher voltage, and additional capacitance in stacked
plate capacitors can be easily obtained. The trick is to use
thinner dielectric.

Now the dielectric strength of polyethylene is given as
1000 volts per mil, but this is not the case in Tesla coils.
The standard breakdown voltages of a dielectric are calculated
using DC voltage. When you run AC across the dielectric, the
breakdown voltage must be divided by two. Then you must figure
that the peak voltage from a AC sine wave is higher than the
rms voltage most people go by. You meter won't see it, but your
dielectric will. Then you have resonate rise in the Tesla tank
circuit. To give you an idea of resonate rise in a tank, think
about the tidal forces that can be created with timed pushes in a
bathtub. It don't take much energy to push water over the side.
The same principal operates in the tank circuit in a coil,
especially with a synchronous gap system. The current pulsing
back and forth from capacitor plate to capacitor plate causes a
voltage rise that appears on the dielectric in the capacitors.
The standard 60 mil poly is supposed to hold up to 60,000 volts
per the book. I have blown holes through 60 mil poly with a 12 kv
neon sign xfrmr in a Tesla tank circuit and my gap wide open. My
pinky finger fit inside the hole.

One of the neatest homemade stack plate caps I have seen was
built by Bill Richards of T.C.B.O.R., the cost was pretty low,
the materials came from his laundry room, the grocery store, and
the drugstore. The only thing required was 56 hours of time in
arranging the plates according to Bill. But he did end up with
.03 uf 15 kv pulse capacitor in a five gallon bucket. It was
quite a performer on his coil at 3600 watts!

He shopped around for one gallon ziplock freezer bags with a 3
mil thickness. With a sharp scissors he cut the ziplocks off of
the tops of the bags. Then he cut aluminum foil squares that fit
inside the bag leaving a 1/2" of space around all four sides of
the plate. So the plate had dielectric borders 1/2" on all sides.

When two bags were stacked on top of one another, there were two
layers of dielectric, for a total of 6 mils. Being practical,
Bill figured correctly that the stacked bags would hold up to at
least 1000 volts rms input in the Tesla tank. He built up stacks
that had a value of about .45 uf each, with each stack rated at
1000 volts. Then he wired stacks in series.

By squeezing fifteen stacks vertically into a bucket, and
covering the whole thing in about three gallons of mineral oil,
he got the required capacitance at the required voltage. Since
the electrical forces are so well distributed among hundreds of
dielectrics, he had plenty of breakdown safety margin. He gave
the unit a couple of days to rest after construction, topping it
up with oil as required, and gave her the works at 15 kv on a big
coil. The heavy buss wiring never even got warm, and even though
it bubbled out enough air to displace a few more pints of oil, it
did not break down.

It turns out that this is a homemade version of commercial pulse
discharging capacitors. Stacked capacitor sections of very high
value are placed in series until the proper voltage requirement
is met. The cap has a very high Q because all of the plates are
very close together, with a minimum of connections and bussing
required. They deliver a very sharp pulse discharge.

Bill's cap was pretty cramped in the bucket. Because of the
square shape of the bags, a rectangular tank would have made
things easier to fit and wire. But he ran his buss bars through
the side of the bucket (sealed with hot glue) and by snapping on
the lid, he could pick it up by the handle and move it around
with ease.

The novice coiler should think about the capacitor requirements
and experiment some before beginning large scale homemade caps.
Shop for materials; frequently a wholesaler can be found where
bulk products (like mineral oil in 5 gallon pails) can be
purchased for a fraction of the retail cost. But just because
you don't have some big bang pulse caps on line does not mean
that you should wait to begin firing a small coil. Nearly every
beginner gets hir feet wet in salt water capacitors.

Tesla used salt water tanks in Colorado Springs. A tribute to the
genius of the man was his ability to develop his huge peak
powers using low Q saltwater/glass caps. I do not recommend glass
as a dielectric for coiling work. The dielectric constant is much
better than plastic, but the RF dissipation factor is so great
that they can rupture from dielectric heating (even in salt water
the trapped water under the bottles does not circulate) and they
always give a spindly, violet colored spark. Polyethylene again
is the material of choice, and bottles and buckets can be
assembled in a couple of hours that will fire small stuff. I
mentioned he before that I have a friend who is firing 5 kVA
coils, and still using banks of salt water caps to keep his
investment down. As with any homemade capacitor, the salt water
must be covered in oil to suppress surface corona. But the
quality of oil need not be high, and the capacitors need not be
exceptionally clean. A saturated solution of rock salt is all
that is needed for the plates.

I think I have accomplished what I intended to say on this
subject. As always, I am happy to respond on any unclear areas,
the need for additional information, or to note corrections.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-16-93 10:49
From: Richard Quick
To: Dave Halliday
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
DH> Thanks for the clarification re: the Schedule 40 pipe - I
DH> had always looked at it as being heavier so therefore
DH> "better" - never thought of the actual material as being a
DH> liability. What about ABS - is there any difference with
DH> that?

I don't have any experience with ABS plastic secondaries. I have
seen some, but had nothing that I could compare to. Look up the
RF dissipation factor and that should give you some idea. Off the
top of my head, I would GUESS that ABS would work better than
PVC; not because I think ABS is any better, but because I know
PVC just couldn't be much worse. If I were using ABS I would dry
and seal the plastic like PVC.

DH> Anyway, we will probably do a couple capacitors in the next
DH> week or so. Like I said, I have an OK vacuum pump ( I do
DH> graphic arts and printing ) and can pump it out so that
DH> should improve things.

Good luck on the rolled caps, and look for some different
capacitor designs in the next few days.

DH> Anyway, many many thanks for your time and help!

No problem, glad to be of assistance.
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Msg#: 3004 Date: 11-18-93 15:22
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Primary coils

In order to move towards a complete presentation we need to talk
primary coils. This will take me one step closer to coverage of
of the major components in the basic 1/4 wave oscillator.

The primary coil is a low resistance, heavy coil, through which
the currents produced by the pulse capacitance travel. In
discussing primaries we need to cover the "skin effect". Both
high voltage and high frequency currents exhibit a property
called skin effect. Skin effect describes a situation where the
current does not penetrate the conductor, but instead flows on
the surface of the conductor. This effect is very pronounced in
Tesla tank circuits where both high voltage and high frequency
are components of the capacitor pulse.

Studies of the Tesla tank circuit current show that the RF
current ringing through the tank has very little penetration of
the tank circuit conductors. This should be reflected in the
choice of the conductors used to wire the tank circuit, and to
wind the primary coil.

I have had very good luck with conductors that offer a lot of
surface area, as opposed to a large solid cross section. The
preferred material for winding primary coils is thin wall soft
copper water pipe or refrigerator tubing, wide sheet copper
strap, or heavy braided copper ground strap. These materials
offer a low RF impedance, high Q, and large radiating surface
areas.

For wiring the Tesla tank circuit, such areas as buss connectors
to capacitors, tap leads, and spark gap connectors, any of the
materials above may be used, but I prefer heavy DC transmission
wire. The DC transmission wire (like battery cable or welding
cable) offers flexibility and this material is available with a
high grade insulation which helps prevent breakdown. The cables
and connections should be carefully examined for areas where Q
can be gained. Sharp edges or points should be removed to prevent
corona losses, connections should be tight to reduce impedance,
and sharp turns should be eliminated to reduce "off axis"
inductance. The tank circuit wiring should be as short and
straight as possible.

The primary coil itself should be wound on a high Q insulator.
For a coil form or coil supports, high density poly, plexiglas,
lexan, acrylic, or other high Q hard plastic is ideal. The
primary coil should be large. I have seen lots of holdovers from
the classic age of coil building who insist on 2-3 turn primaries
and HUGE capacitors to achieve the proper frequency of operation
in the tank circuit.

This is wrong.

A tank circuit with a small capacitor, and a large primary
inductance, will reach down to the same frequencies of operation.
A tank circuit of this design will use less power, and therefore
require a smaller step up xfrmr. The capacitor will be smaller,
which further reduces the cost of the system.

A large primary coil offers a much greater surface area for
radiation and distributed energy transfer to the secondary. It
couples better with a properly designed secondary. Due to these
design advantages, an equal or greater amount of power is
actually delivered to the secondary, despite the much smaller
capacitance and input power. Using a large primary will allow you
to reduce the value of your capacitor and your input power by 50%
or more (frequently much more) without a reduction in output.

Primaries designed to be operated with 9-15 turns will obtain
power processing energies that are at least 50% greater than 2-3
turn primaries, provided that the secondaries are constructed to
take advantage of the design. Secondary coils with the aspect
ratios and numbers of turns that I have recommended here before,
work best with large primaries tapped at 9-15 turns.

So to give some advice to my friend Dave Halliday, who is
building a 6" secondary coil sometime in the near future,
plan on winding a primary coil from a conductor material that I
have listed above, and use a conductor length of around 75 feet.
Your primary should end up about as wide as, or wider, than your
secondary is tall.

This way the secondary will nest in the large primary. The field
flux from the primary will couple the entire length of the
secondary winding for a distributed, high efficiency, energy
transfer. More energy can be forced into the secondary, with
lower input power, and reduced chance of breakdown and loss.

Primary coils take several forms depending on the type secondary
used with them. Modern secondaries, with high inductance and low
aspect ratios, need primaries that are flat pancakes, or "saucer"
(rising upwards as the turns move out) shaped spirals. Because
this design is so efficient in energy transfers, critical
coupling coefficients are achieved without using the old fashion
vertical helix type primary coil.

When designing primary coils, it is generally a good idea to test
a particular coil shape before committing to a time consuming and
expensive permanent coil. This is especially true for those who
have not had much experience with primary coils of different
shapes and sizes. Some cheap low Q wire can be picked up and used
to make a temporary primary coil for testing. I set the secondary
up on an insulated platform equipped with a good ground, then
wind the test primary. To achieve the desired shape I use tire
tubes (to build up "saucers") plastic wedges, tape, etc.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-18-93 11:45
From: Richard Quick
To: Mark Lawton
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
ML> Sounds just like my stuff! Change the Vespas to dirt bikes
ML> and you've got it. I haven't built a coil in a few years,
ML> but I'd like to send you a blank VHS to get a copy of your
ML> work. Write me back with details on where to send the tape
ML> and the dough.

Richard T. Quick II
10028 Manchester Rd.
Suite 253
Glendale, MO 63122

Send a two hour blank VHS high quality tape. $10.00 and a self
addressed postage pre-paid mailer. The tape will be return mailed
the morning after I get your package. I have sent out three in
the last three weeks, so don't worry about me getting rich off
this.

BTW I will trade video even, tape for tape, for coil, rail gun,
high powered laser, and other high voltage stuff. My tapes are
one off masters, recorded on SP for highest quality, and a full
two hours long.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-19-93 14:38
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Toroid Discharge Terminals

Another feature of the "classic" Tesla coil design is the sphere
or ball discharge terminal. Tesla clearly was using spheres while
he was developing the Colorado Springs oscillator, but during his
work there he made the discovery of toroids. Photographs of the
Colorado Springs machine clearly shows a brass toroid as part of
the antenna mast to prevent corona leakage and premature breakout
from the top of the extra coil.

As we examine photos of the Wardenclyff machine he built on Long
Island, it is clear that the entire tower was constructed to
carry the giant toroid terminal. I do not have verifiable inform-
ation as to the exact size of this terminal, but it is easily
over 50' in diameter. Probably closer to 75-100'. Toroids perform
several functions as discharge terminals on Tesla coils.

They provide a large top capacitance. This top capacitance helps
"cancel" the high inductance in the secondary coil, and increase
throughput in the system.

They break down at much higher voltages than other shapes. The
donut shaped field distributes the charge density. Higher
voltages must reached before electrical breakdown occurs. To the
coiler this means longer, higher voltage spark. For those of you
that have my video, you can see a 30% increase in spark lengths
with no change to input power, the only thing I did was add a
larger toroid and retune the system.

Toroids sever the coupling. This may be a controversial statement
on my part. But from what I have seen, appears to be true. A
sphere discharge terminal does not want to separate from the
field flux interactions between the primary and secondary. The
primary field flux wants to couple the sphere discharger into the
system as if it were another turn of the secondary. The spark
from the discharger will frequently follow these lines of force,
and seek to strike back to the primary. The spark discharge bends
back down, and aligns itself with the magnetic lines of force.

While this may be useful if you wish to visualize the size and
shape of the field, it does nothing to increase your spark
lengths. A large toroid on the other hand will establish a field
identity that interacts destructively with the primary/secondary
field interaction. Since this destructive interaction occurs
above the top turns of the secondary is does not affect the coil
performance or ability to process energy. It does however allow
the spark to leave the system unaffected by the primary/secondary
lines of force. This has the effect of allowing a clean getaway
for the discharge and promotes those long strikes to the ground
or other more distant objects.

Toriods also have the beneficial effect of lowering the frequency
of the secondary coil dramatically. By loading a large toriod on
a relatively small coil, a very low secondary frequency is
reached. Low frequency in Tesla systems means long spark. This
way a small coil can give big coil performance. Because of this
ability of the toriod to drop the frequency of the secondary to
such low frequencies, it is important to have a very large
primary available that can be tapped out to over 10-12 turns in
order to regain the system tune. Larger capacitors may be added,
but my experience shows that no additional power or capacitance
is required to get big increases in spark production.

Clearly the toriod is the ultimate in high Q dischargers and
radiators in Tesla systems. Now go out and buy one. I can hear
Dave Halliday now..... "You Paid _HOW MUCH?_"!!!
Yup, spun aluminum toroids are available commercially, and they
run hundreds, even thousands of dollars each. My 20" wide by 5"
high commercial toriod ran me over 350 clams. My ten inch
secondary needs a toroid at least twice as big to achieve optimum
performance, and as commercial toroids get larger, the price
increases exponentially. I priced a 40" toroid for my coil at
$2000.00 not including shipping, and they gave me a six month
delivery time...

So I built one for $35.00, and it works GREAT! I will never spend
another penny on commercial spun aluminum toroids. Here are the
brief instructions:

I buy the 4" or 6" diam. polypropylene flexible black plastic
drain piping. This is made out of ridged plastic, so it does not
have a smooth surface, but it easy to bend to form circles of
varying diameters.

I cut the flange off with a sharp knife, match the ends, and tape
them together with wide plastic tape. Once a large ring is
formed, I cover the entire surface with wide plastic tape to
smooth out the ridges in the material. The goal is to have an
even, smooth, surface. The tape choice helps with this con-
struction, Mylar and other tapes have no stretch, and are
difficult to work with as they wrinkle. I shopped several stores
before I found a stretchy material similar to electrical tape.
Tape is applied in overlapping strips, or bands, around the drain
pipe 4" or 6" cross section. Some surface irregularities are OK.

Once the ring is smoothed with a layer of plastic tape, I retape
the entire ring with aluminum plumbers tape. This tape comes in
two standard widths, I bought a large roll of each. Apply strips
of plumbers tape over the prepared surface, make sure the entire
surface is covered, and press out any wrinkles with a fingernail
or tool. You should now have an aluminized ring. Cut out a circle
of thin masonite, wood paneling, or thin plastic so that it will
friction fit in the center of the aluminized ring. Place some
blocks up under this panel, set the ring in place, and tape the
edges all around on both sides with aluminum tape to hold it in
place. Spray adhesive and heavy duty foil are used to cover both
sides if the center plate. Roll out all wrinkles with a socket or
a wood dowel. Works great, about 1/100th the cost.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-19-93 16:49
From: Richard Quick
To: Dave Halliday
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
>recently gutted. When I inquired, he stated he had to switch to
>an ungrounded, wooden, control cabinet because he was drawing
>sparks to fingers when he touched the controls...

DH> I also recall stories about ham radio shacks having this
DH> problem.

DH> Used to work for the public aquarium in Boston and we had
DH> grounding problems like you wouldn't believe - I was
DH> responsible for all of the non-living exhibits ( PA and AV
DH> stuff ) and the ground at every single outlet was at a
DH> different potential than any other outlet. I once found 50
DH> volts difference between two located 20' apart... A guide
DH> was setting up a temporary exhibit and used both outlets for
DH> their equipment. They got a bit of a rude awakening that
DH> day <grin>

A few months back when our local sysop first added this
conference, there was an thread on grounds and grounding that you
just would not believe (well maybe you would), anyway, the
misunderstandings and misconceptions about grounds and grounding,
and the bizzare things that happen when equipment and systems are
not properly grounded...

I have threatened to write a book on the subject and post it
chapter by chapter!

Tesla was the first person to apply ground to a tuned circuit.
His studies of grounds, and grounding practices was extremely
extensive, but unfortunately little was documented or survived.

By reading the Colorado Springs Notes it is quite clear that
Tesla struggled to get a good ground on site for his system and
cited the local geology (sand & rock) as the source of his
problem. He eventually had to run water 24 hours a day over his
ground.

He used a two ground system in his CS lab, and documents the
resistance, and electrical distance between the two. The system
ground was a 3' square copper plate dropped in the bottom of a
12' hole with a couple of wheelbarrows of coke dumped on top.
The hole was backfilled and watered as I mentioned.

His control, or line frequency, ground was the water pipe. Tesla
was capable of producing serious ground currents from the
machine. Some of the effects were reported many miles away;
sparks coming off the shoes of horses which caused the
animals to spook, clouds of insects covered in St.Elmos fire,
in addition to the locals getting sparks from their water taps.

When he went on to Wardenclyff, he spent half of the tower
construction cost on the well with 18" copper plated steel pipe
driven into bedrock 50' below the water table. He did not intend
to mess around.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-19-93 17:04
From: Richard Quick
To: David Tiefenbrunn
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
DT> I have sent you a video tape. I hope the
DT> offer is still good. I included a few
DT> minutes of the first run of the 45KW generator.

DT> The new lab sounds great.

DT> Of course, you will probably get the tape before
DT> this message. :)

Yeah I did! And you will probably get the tape back before you
get this message. It went out yesterday. Yes the offer is still
good, and so is the tape. You will really enjoy watching it.

New lab so far is looking good. Expensive, contractor wants
$32.50 per square foot.

Read my letter in with the tape about the generator video. I am
still kicking myself (I recorded over it before I read your
letter)

BTW I will trade tapes happily if anyone has goodies I would be
interested in. Video tape is an excellent way to archive our
little projects; not only are they useful as a personal
reference, but they are amazingly effective teaching tools.
Nothing explains something like a coil project as well as the
designer/operator pointing to, and talking about, the operational
working equipment.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-20-93 00:42
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ

Tesla Coil Builders Association

I posted this address a few months back, but many people dropped
in recently so I will post it back up again. The organization is
called TCBA for short and is run by one, Harry Goldman, retired
high school science teacher. He publishes a quarterly news letter
called _NEWS_

The news letter has articles submitted by members on a regular
basis, new coil designs, sparks gaps (my first submission was
published here), spark photos, articles on "classic" coils
gleaned from age old science magazines, questions and answers
sections, as well as a "trading post" buy and sell section for
new and used HV caps, xfrmrs, coils, coil forms, etc., and a list
of the best commercial parts suppliers.

Subscriptions and membership is $24.00 U.S., $30 CAN., and
includes a framable certificate.

Harry has been publishing the NEWS since 1982 and all back issues
are available as well a comprehensive index of all articles in
those back issues. If you are interested write to:

Harry Goldman
TCBA
3 Amy Lane
Queensbury, NY 12804
Tel: (518) 792-1003

Tell him I sent you!!!

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-17-93 23:52
From: Dave Halliday
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
RQ>never stare at an operating spark gap without welding goggles.
>To examine the arc on large coils, a sun observation filter
>on a small telescope will tell you if your gaps are quenching.

RQ>... And if all else fails... Put another megavolt through it

I got your whole post on Spark Gaps - Once again - Thanks!

I had an experience with hard UV light - purchased a small
Lincoln Wire Welder and proceeded to ignore the instructions
about covering all parts of the body - I was thinking about metal
splatters but I never thought about the UV light - wearing
sandals at the time and got a bad sunburn on my feet...

Status report:

Got the wire for the secondary as well as the basic design.

I got the 50' of AL flashing for the capacitor as well as all of
the PVC pipe and already had the nuts and bolts...

Also, found a *wonderful* three terminal plus ground RF filter
for 240 volt -at- 60 Hz rated at 60 amps! $20 - couldn't resist! I
will be able to keep the rest of the electronics in my house ( as
well as the neighbors houses ) somewhat happy :)

Still looking for a source of the form for the secondary - will
be checking prices at local plastics stores when I go to get the
60 mil. Polyethylene sheet - if not, I will use thin-wall PVC but
the stuff I saw at a local Home Depot was poorly out of round...
Maybe some plexiglass disks glued inside to maintain shape.

The local Boeing Aircraft Co. has an interesting "surplus" store
that is a little toooo well known but might have something there.

Have a bunch of 3/8" refrigeration tubing that I can use for the
primary - also into home brewing and this stuff comes in handy...

Still need to get the step-up transformer - already have a 12kV
30mA neon but the "potential" transformers you mentioned that
were used in power substations sound very good too - will check
locally.

Pole pig will probably be somewhat later although the
demonstration you did on your video - using it - were pretty
impressive - the simple Jacob's Ladder was way beyond what a 15kV
neon can do - had a really nice sound to it!

Anyway - work progresses - I will be busy during this "holiday"
season, also the people that were interested in working with me
are still very very much interested - showed the primary person
your video and their jaw dropped <grin>

p.s. - an idea for the gap - you could have a rotary system that
also had a valving plate ( circular plate with holes drilled into
it ) where the output of the valves could be forced over the
spark gaps - pulsed air quenching of a rotary gap - I have a
small metal lathe and this might be something to do...

As always - Dave 301-794-6496 (1:109/546)

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-22-93 03:18
From: Richard Quick
To: Dave Halliday
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
DH> Status report:

DH> Got the wire for the secondary as well as the basic design.

OK, I got some soft figures for you. Given the specs of the
planned coil you gave me here's what your looking at:

Bare secondary frequency around ~260 kHz
Secondary top loaded with 18" diam, 4" cross section toriod will
resonate around ~180 kHz

Using the rolled capacitor as per my specs you should get .02 uf
capacitance, so to tune this secondary in on the tank circuit,
your tank will have to be: Saucer shaped spiral wound primary.
Angle of inclination from first turn to last turn will be right
around 30 degrees slope; this should give pretty close to
critical coupling with this secondary. Diameter of the first turn
(inside diameter) will need to be ~9" giving you 1-1/2" space
between the coils. With the toroid discharge terminal on the
secondary coil, the tank should tune in when the primary is
tapped right around 9 turns.

These numbers are going to off a little, but I tuned a guys coil
once over the telephone when he was six states away. I was
throwing stuff off the top of my head and set the coil up in my
mind from his verbal description. He claimed I had the coil in
it's best tune the first time he turned it on, said every time he
altered anything the spark decreased. It COULD have been dumb
luck... But I checked the numbers you gave me against my programs
and my documented systems in this size. You'll need at least 9
turns on a saucer primary to get that coil to fire with that cap.

DH> I got the 50' of AL flashing for the capacitor as well as
DH> all of the PVC pipe and already had the nuts and bolts...

Your looking good here.

DH> Also, found a *wonderful* three terminal plus ground RF
DH> filter for 240 volt -at- 60 Hz rated at 60 amps! $20 -
DH> couldn't resist!

I would have picked it up too. This is looking good, be sure to
run the filter backwards. If your using only one filter, place it
between in the supply line before the variac. Ground the case to
your 60 cycle neutral.

DH> Still looking for a source of the form for the secondary -
DH> the stuff I saw at a local Home Depot was poorly out of
DH> round...
DH> Maybe some plexiglass disks glued inside to maintain shape.

I would avoid using baffles inside the coil form, they tend to
reduce the Q of the coil. Find a different supplier for some
rounder pipe before you go this route.

DH> Have a bunch of 3/8" refrigeration tubing that I can use for
DH> the primary -

Just fine for this sized primary coil, make sure it is long
enough, though you can braze in a splice for added length.

DH> Still need to get the step-up transformer - already have a
DH> 12kV 30mA neon but the "potential" transformers you
DH> mentioned that were used in power substations sound very
DH> good too - will check locally.

If you use 12 kv neons you will need about 120 ma total to drive
this coil to good spark. That's four 12,30s.

DH> Pole pig will probably be somewhat later although the
DH> demonstration you did on your video - using it - were
DH> pretty impressive - the simple Jacobs Ladder was way beyond
DH> what a 15kV neon can do - had a really nice sound to it!

I should hope so!!! I run the Jacob's Ladder between 5-7 kVA with
a rail voltage of 20,000 volts.

DH> Anyway - work progresses - I will be busy during this
DH> "holiday" season, also the people that were interested in
DH> working with me are still very very much interested - showed
DH> the primary person your video and their jaw dropped <grin>

His was not the first, and won't be the last!!! You should have
seen the look on MY face while I was running it! I was 20' away
and under cover and the sparks looked like they were going to
wipe my nose for me.

DH> p.s. - an idea for the gap - you could have a rotary system
DH> that also had a valving plate ( circular plate with holes
DH> drilled into it ) where the output of the valves could be
DH> forced over the spark gaps - pulsed air quenching of a
DH> rotary gap - I have a small metal lathe and this might be
DH> something to do...

I think I understand the idea, may be a good one. I can give you
specs for basic systems that will give excellent performance. But
for ideas like this, I encourage people to develop as far as
profitable.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-22-93 18:53
From: Richard Quick
To: All
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Tuning The Tesla Tank Circuit

Once a Tesla coil is set up and ready to fire, certain steps
should be taken before power is applied. Don't expect to throw
the works on a newly built or newly re-arranged system. If you do
you may have to go back to the drawing board. The coil must be
brought into tune, and up to power gradually.

The use of a variac autotransformer is highly recommended for
controlling power on a system, even if the coil is eventually to
be used in on/off applications. Never throw full power to a coil
until you are sure the system is in proper tune.

Set the tank circuit up first. Double check all of your
connections. Run your grounds and double check those, never take
a solid connection for granted. Set the secondary into the
primary and ground it. Use a small discharge terminal at first if
available. The smaller terminal will break down and produce spark
at a lower voltage than a larger terminal, and new setups are not
the place to stress the secondary.

CLOSE YOUR SPARK GAPS DOWN! This is the numero uno step in
bringing a coil into tune, don't run a lot of gap. I set up a
static test with the power supply and no capacitors. Close down
the safety gap until it has reached the point where the
transformer will jump the gap 50% of the time when full voltage
is applied in the test. Measure this gap distance and record it.
When tuning a coil you will reduce this safety gap distance by
50% to provide kickback protection. It is a good idea to run a
static test on the main system spark gap and close it down by 75%
But on some gap systems this may not be practical, as series gaps
behave much differently that a single gap. These differences are
caused by the opposing lines of force in the single gap used for
the safety.

Apply a bit of power until the tank circuit fires. If no spark
breakout is seen from the discharge terminal don't worry. Use a
florescent bulb as an indicator. As the coil is closer to tune,
the farther and brighter the bulb will glow. Turn off the coil
and move the tap connection on the primary coil a half turn and
check the bulb brightness, then move it a full turn in the
opposite direction and note the brightness of the bulb again.
This way you can determine the direction the tap needs to be
moved to locate the tune spot.

Open the main and safety gaps up in steps. Apply the same voltage
input (low power) and check for discharge. Once spark has begun
to break out of the discharge terminal use it as a visual
indicator of tune as long as full power is not applied. With full
power into a system the spark frequently gets so wild and
distracting you cannot judge accurately. I have found that
recording the tuning on video, and watching the tape provides a
way to look at the system objectively.

A system in proper tune should not break down the safety gap. The
safety gap set at the full static test setting should not be too
active. Once the coil is in good tune the safety gap electrodes
may be opened to the point where the gap only fires perhaps once
every three or four seconds weakly.

Tuning is an art, and it takes a little practice. I recently came
across some information that will be quite helpful for the novice
(and even an expert on high powered systems) obtain better
tuning. Use an arc meter.

The arc meter is made by suspending a series of gaps on
monofilament fishing line. One end of the arc meter is connected
to the toroid, the other end of the meter is strung across the
room and grounded.

By placing a series of air gaps on an insulated line, the arc
strength and voltage may be accurately gaged with the eye.
Discharge will follow the gap path (it looks like a ray gun
firing) and gaps may be counted as a reference.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-21-93 22:40
From: David Tiefenbrunn
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
On 11-18-93 Richard Quick wrote to Dave Tiefenbrunn...

RQ> Got your tape out this morning. Let me know that you got it
RQ> and

Tape received 11-20-93. As was the post quoted herein.

RQ> what you think of the spark. I was checking the tape for a
RQ> minute as it was recording... Even I forget sometimes how
RQ> awesome a 10" secondary looks with a proper discharger and
RQ> 10 KVA pumped cleanly through it. I think you will agree,
RQ> get back with me.

*Quite* awesome... Previously the largest Tesla coil
I had seen was in a science museum in Boston, MA.
It's spark was maybe 1/2 of the >small< coil in your
video. I *used* to think it was a big one.

At what power level does it become dangerous to draw spark with
the pole?

The one I built when I was in college (over 10 years ago) had
230W input, but I didn't have all the details of how to optimize
/ tune it. It still threw sparks a few inches long. It also had
a nasty static charge that would build up while it was running,
and while I drew sparks (with a rod) the static charge would
pop and I'd get a jolt. Your coils never displayed that
particular problem in the video, just nice clean HV RF. I'm going
to show a few friends your tape. One of them has a small (by
your standards) coil. His coil's primary is wound like a regular
coil, not flat like yours (or for that matter, the others I've
seen. I will have to check with him to find out why. I think he
is using flat glass / foil caps. With a little luck & timing
maybe I can get video of it when we do the generator tape deal.
(see other post) I have been saving all of the "how to" stuff
for future reference. (203)345-7635 (1:320/5967)

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-23-93 15:21
From: Richard Quick
To: David Tiefenbrunn
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
DT> Tape received 11-20-93. As was the post quoted herein.

DT> *Quite* awesome... Previously the largest Tesla coil
DT> I had seen was in a science museum in Boston, MA.
DT> It's spark was maybe 1/2 of the >small< coil in your
DT> video. I *used* to think it was a big one.

Yup, we have one in our science museum too. Small system putting
out about 2' of spark. I decided I could do a little better if I
put my mind to it.

DT> At what power level does it become dangerous to
DT> draw spark with the pole?

This is a very good question. Very good. I routinely pull spark
off of my coils with a key, pipe, or other conductor. It is not
the power level of the spark that makes a difference, it is the
quality of insulation you are standing on and the distance you
place yourself from ground. I have had sparks coming off of my
shoes over a foot long while in direct contact with voltages of
at least a million volts. I can light 40 watt bulbs from the
CURRENT heating the filament, and my body in series with the
circuit.

Power arcs leaving the body and hitting the ground are very
dangerous, especially for those who are more shock sensitive
than myself. I do not experience "shocks" in these instances, but
do feel the RF burns. I have also had a few RF burns from change,
keys, etc. on my person, as well as having lost all the magnetic
strips on my bank and credit cards. My brother lost a nice
digital watch once.

But, if you know what you are doing, and the system is well set
up in proper tune, it is OK to take up to 5 kVA output through a
conductor to your person. But this is not recommended for
amateurs.

There IS a danger with certain tank circuits. I never ground the
tank circuit or the primary coil, nor do I connect the secondary
anywhere to the tank circuit or the primary. Coils with the
primary and secondary connected, or both grounded to system
ground can be LETHAL!!!! This allows an open pathway for deadly
60 cycle from the step up xformer to appear in the spark
discharge. I avoid this problem by never using these circuits. My
tank circuits and primary coils float ungrounded. Remember tank
circuits are always deadly. A person with a conductor in hir hand
and approaching a Tesla coil had better know the circuit, and
have a cool head. Accidental contact with a primary coil or tank
circuit has thought provoking possibilities.

Like I stated in my original post when offering video: I cannot
be responsible for people attempting to reproduce any of the
experiments that I perform on the tape. I know what I am doing.

DT> The one I built when I was in college (over 10 years
DT> ago) had 230W input, but I didn't have all the details
DT> of how to optimize / tune it.

You do now!

DT> It still threw sparks a few inches long. It also had a
DT> nasty static charge that would build up while it was
DT> running, and while I drew sparks (with a rod) the static
DT> charge would pop and I'd get a jolt. Your coils never
DT> displayed that particular problem in the video, just nice
DT> clean HV RF.

Yup, they do run clean. Very little RFI, high output, and
efficient. Even my little temporary test setups perform better
than most peoples end product. Having seen a lot of coils, and
talking with people that build them, I feel qualified to post
to "ALL". Nobody here has said any different. I know the circuits
and systems to the point where I literally dream about them
sometimes. I have set up and fired systems in my dreams several
times, and I find the data I get from there is as valid as
anything I do while awake.

DT> I'm going to show a few friends your tape.

Please do. All I ask is that you do not make copies without my
permission.

DT> One of them has a small (by your standards) coil. His
DT> coil's primary is wound like a regular coil, not flat like
DT> yours (or for that matter, the others I've seen. I will have
DT> to check with him to find out why.

Most likely his plan or design hails back to the "classic" era of
coil building where a vertical helix primary (all primary turns
equally spaced from the secondary) was common. This type primary
is used to couple energy into systems using the "classic" style,
space wound or low inductance secondary coil. The design I
promote has been completely modernized and takes full advantage
of modern high Q construction materials. The very high inductance
secondary is so much more efficient that you have to reduce the
aspect ratio of the primary coil or it will force a breakdown of
the secondary from overloading. Then I use toroids to balance the
secondary right to the load limit. The result of this work on my
10" coil has yielded sparks to the strike rail protecting the
primary that are as fat as my leg, and up to 15' full current
strikes. The spark is fully five times the length of the
secondary winding which is only 32" high.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-21-93 23:01
From: Dave Halliday
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
RQ> Primary coils

RQ>In order to move towards a complete presentation we need to
RQ>talk primary coils. This will take me one step closer to
RQ>coverage of the major components in the basic 1/4 wave
RQ>oscillator.

Once again - THANKS!

Also, just had a bit of a "conceptual" breakthrough - was trying
to see why 1/4 wave was best and then saw that this is 1/4 wave
reflected over a ground plane...

Makes a lot of sense ( arcs too )

Again, this has been saved, will be printed tomorrow.

TTYL - Dave �:-)

::Status report::

Got some PVC pipe - flimsy stuff but I will use wooden braces to
hold it circular while I wind it. Actually, will probably cut
out some plexi circles and glue them in... Got a bunch from some
old signs

Still have yet to get to the plastics store to get the material
for the capacitors but looking at this week - also probably
"have" to make a run to one of our distributors located near the
Boeing surplus store - check for Teflon wire as well as "exotic"
6" tubes...

Question - there are some very cheap cutting boards available
made out of a high-density polyethylene plastic - was thinking of
using them for the "breadboard" for the transformer protection
stuff as well as the base of the coil - do you have any feedback
on the Q of this material

Thank you for your post on Primary coils - haven't read it
completely but I got the idea that the diameter was critical -
will check and get large tubing if that is true...
301-794-6496 (1:109/546)

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-25-93 11:59
From: Richard Quick
To: Dave Halliday
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
DH> Once again - THANKS!

No problem

DH> Also, just had a bit of a "conceptual" breakthrough - was
DH> trying to see why 1/4 wave was best and then saw that this
DH> is 1/4 wave reflected over a ground plane...

DH> Makes a lot of sense ( arcs too )

Yeah, It took me a few minutes of looking at sine, then a 1/4
wave antenna before I realized what was going on and was able to
conceptualize in my mind. Only then did Tesla's repeated use of
the terms "fundamental note" and "harmonic" make sense.

The length of wire vibrates electrically and is more or less the
perfect analogy of a musical string. When the length of wire is
wound to form a coil, it is simply compressed into a smaller
volume where it can be efficiently excited.

Now you can force that length of wire to accept SOME energy at
any frequency, but the wire has a natural "hot spot" of
resonance, just like a musical string has it's natural note.

A function of the coil, and it's natural resonance, is such that
it offers low impedance at the base for currents that match it's
natural resonate frequency. So if the coil has a natural
resonance of say 250 kHz, and current at 250 kHz is fed into the
base, the coil will take it up. Current will flow. Current of any
other frequency sees a very high impedance.

But at the top of the resonating coil you do not see current. The
coil "converts" the base current into a voltage at the other end.
Since this voltage rises as you go higher and higher up the coil,
and reaches it's peak at the top; Tesla was able to determine the
voltage at the top of the coil is the first 1/4 wave voltage peak
of the RF current fed into the bottom.

A good term to introduce here is VSWR, for Voltage Standing Wave
Ratio. The coil at resonance establishes a standing wave of the
resonate frequency. The bottom of the wave is a low potential,
such as your RF ground. From this low potential base, the
standing wave is established, and voltage increases as we move
higher up to the top of the coil.

In order to get a handle on the true resonate frequency of a coil
I use a signal generator, o'scope, and a frequency counter. The
signal generator produces about a 2 volt signal that can be
varied in frequency. I place a 1K resistor between the signal
generator output and the o'scope input. Now the o'scope measures
voltage. The higher the wave on the scope, the higher the voltage
present in the signal generator output.

The output of the frequency generator is fed to the base wire of
the coil, and the frequency of the output is varied while
watching the o'scope. When the frequency of the signal generator
matches that of the coil, the coil takes up the current. Because
current flows into the base of the coil at resonance, there is a
voltage drop in the signal generator output line. This voltage
drop is measured by the o'scope (across the 1K resistor) and is
know as a "grid dip". The wave on the scope drops to nearly a
flat line. When I see a grid dip I know I have matched the signal
generator output to the coils natural resonate frequency. By also
running a frequency counter connected to the signal generator, I
can tell precisely the frequency of the input current.

So in this little example, with a coil resonating at 250 kHz; the
coil is resonating at 250 kHz and accepts 250 kHz current at the
base. The current flow is high, the base impedance is low. As you
measure voltage up the coil, the voltage rises until you get to
the top of the coil. At the top of the coil you find the maximum
voltage peak. This is the first voltage peak of the RF current
fed into the base, and represents the 1/4 wave point of the
input frequency current. So you have a 250 kHz coil, with a 1/4
wave voltage output. 250 kHz input, 1/4 wave voltage output,
helical resonator; or 250 kHz 1/4 wave Tesla coil.

We know the coil does not require current fed to the base to
become excited. Oscillating magnetic field flux at the resonate
frequency will highly excite the coil. The coil also having the
property of inductance. So the coil can become highly excited by
placing it in close proximity to a high powered oscillator, which
is the Tesla tank circuit. Excitation by field flux produces
equal energy output from both ends of the coil. Current from the
bottom, and voltage from the top. It becomes clear now why such
heavy RF grounds are required for Tesla coil work, and why the RF
ground must be isolated from all other equipment.

DH> ::Status report::

DH> Got some PVC pipe - flimsy stuff but I will use wooden
DH> braces to hold it circular while I wind it. Actually, will
DH> probably cut out some plexi circles and glue them in...

Plug the ends of the coil form with something to hold it round
while it is wound. Once wound, the wire will stiffen the coil
form and hold the shape. When you glue the end caps on the form,
it will be plenty sturdy.

DH> Question - there are some very cheap cutting boards
DH> available made out of a high-density polyethylene plastic -
DH> was thinking of using them for the "breadboard" for the
DH> transformer protection stuff as well as the base of the coil
DH> - do you have any feedback on the Q of this material?

Pretty good choice of material for a filter board.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-23-93 23:43
From: David Tiefenbrunn
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
On 11-19-93 Richard Quick wrote to David Tiefenbrunn...

RQ> New lab so far is looking good. Expensive, contractor wants
RQ> $32.50 per square foot.

Have you "shopped" the local contractors much? I would thing you
could get a pretty good deal with the terrible recession were
in.:) In CT things are still slow, anyway.

RQ> BTW I will trade tapes happily if anyone has goodies I would
RQ> be interested in. Video tape is an excellent way to archive
RQ> our little projects;

I agree. I still sometimes forget to get the dang thing before
"throwing the switch" though.

RQ> not only are they useful as a personal reference, but they
RQ> are amazingly effective teaching tools. Nothing explains
RQ> something like a coil project as well as the designer/
RQ> operator pointing to, and talking about, the operational
RQ> working equipment.

Of course, most of my projects haven't been as striking as the
10KVA Tesla coil, but it is nice to have them on record.

BTW, is that Tesla Coil Builders Association sticker on the big
control panel for real? I never in 1K years would have thought
there was such a thing. Dave (203)345-7635 (1:320/5967)

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-24-93 01:29
From: George Powell
To: Richard Quick
Subj: Re: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
I bet tesla was a fun person to live by..made the locals life
real interesting.. ;) (1:2460/21)

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-27-93 00:52
From: Richard Quick
To: David Tiefenbrunn
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
DT> On 11-19-93 Richard Quick wrote to David Tiefenbrunn...

RQ> New lab so far is looking good. Expensive, contractor wants
RQ> $32.50 per square foot.

DT> Have you "shopped" the local contractors much?
DT> I would thing you could get a pretty good deal
DT> with the terrible recession were in.:) In CT
DT> things are still slow, anyway.

Yeah, I'm going to go "shopping" as soon as I can get motivated
to spend 100G. Right now I am catching my breath from the sticker
shock. The building should go up fast, and I don't plan to start
until spring or early summer. This will give me a chance to shop
around.

DT> BTW, is that Tesla Coil Builders Association sticker
DT> on the big control panel for real? I never in 1K years
DT> would have thought there was such a thing.

Yup It's for real.

Tesla Coil Builders Association
Harry Goldman
#3 Amy Lane
Queensbury, NY 12804

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-27-93 01:26
From: Richard Quick
To: George Powell
Subj: Re: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
GP> I bet Tesla was a fun person to live by..made the locals
GP> life real interesting..

There are several good (and true) stories about the local
disturbances Tesla created.

One of the best concerns an electro-mechanical steam powered
oscillator he constructed. Now the oscillator was built to
provide a constant frequency field current for a RF alternator
in his radio work. But he played around with the thing.

In New York he had a lab in the loft of a building for awhile, I
don't have the exact address, but I can easily reference it if
required. The building had a heavy iron center post in the
construction. The post came up through the center of the loft and
supported the roof peak. The base of the post was sunk into
bedrock, and carried a considerable portion of the building load.

Tesla bolted the oscillator output shaft to the post and fired it
up. As steam pressure in the boiler increased, so did the
frequency of oscillation. He sat in a chair and observed the
effects of the mechanical vibrations on objects at hand. Each
object having a resonate frequency would begin to vibrate and
move as the frequency of the oscillator matched it.

After about 30-40 minutes Tesla began to notice the building
itself begin to sway, and saw beams unseat. He went to shut down
the machine. To his dismay he found that his jury rigged steam
line was too hot to approach, and/or the valve was seized. He
looked around the lab for a minute or two and finally attacked
the problem with an axe, severing the steam line and blowing
clouds of live steam into the building.

As the steam cleared, he heard a knock at the door. Two of New
York's finest stood in the doorway. Now Tesla was apparently no
stranger to dealing with the authorities. He explained to the
cops that they had arrived too late for the demonstration, and
that an unfortunate problem prevented him from reproducing the
test while they waited. He invited them back later in the day,
and showed them out.

It seems the police had received frantic calls from people in a
radius of several blocks reporting an earthquake. Walls,
sidewalks, and foundations cracked, windows shattered, street
lamps tilted askew, and stuff was falling out of cabinets and
shelves. The police realized that the station itself was only
subjected to a slight tremor, but officers reporting to the scene
of the calls found the intensity increased as the drew near
Tesla's lab. It did not take them long to figure out where the
commotion was coming from. As I mentioned, Tesla was no stranger
in dealing with local authorities.

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-26-93 23:28
From: David Tiefenbrunn
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
On 11-23-93 Richard Quick wrote to David Tiefenbrunn...

RQ> DT> *Quite* awesome... Previously the largest Tesla coil
RQ> DT> I had seen was in a science museum in Boston, MA.
RQ> DT> It's spark was maybe 1/2 of the >small< coil in your
RQ> DT> video. I *used* to think it was a big one.
RQ>
RQ> Yup, we have one in our science museum too. Small system
RQ> putting out about 2' of spark. I decided I could do a little
RQ> better if I put my mind to it.

You sure did. :)

RQ> DT> At what power level does it become dangerous to
RQ> DT> draw spark with the pole?
RQ>
RQ> This is a very good question. Very good. I routinely pull
RQ> spark off of my coils with a key, pipe, or other conductor.
...
RQ> Power arcs leaving the body and hitting the ground are very
RQ> dangerous, especially for those who are more shock
RQ> sensitive than myself. I do not experience "shocks" in these
RQ> instances, but do feel the RF burns. I have also had a few
RQ> RF burns from change, keys, etc. on my person, as well as
RQ> having lost all the magnetic strips on my bank and credit
RQ> cards. My brother lost a nice digital watch once.
RQ>
RQ> But, if you know what you are doing, and the system is well
RQ> set up in proper tune, it is OK to take up to 5 kVA output
RQ> through a conductor to your person. But this is not
RQ> recommended for amateurs.

Reminds me of one of my dad's T shirts: I am a professional.
DON'T try this at home. You should get one :)

It would seem that the important thing is to not allow a spark to
jump directly to or from the body.

The first coil I made (back in grade school days) only threw a
spark about 1/2 inch long. But I would let it jump directly to a
finger with no shock or burn. Not enough power to do damage.

I do feel shocks (and burns), so I would hesitate before trying
that with a large coil.

RQ> DT> I'm going to show a few friends your tape.

RQ> Please do. All I ask is that you do not make copies without
RQ> my permission.

O.K. (203)345-7635 (1:320/5967)
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-26-93 01:00
From: Guy Daugherty
To: George Powell
Subj: Re: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
GP>I bet tesla was a fun person to live by..made the locals life
GP>real interesting.. ;)

You might say it brightened up their lives. Brought a little
spark into them, so to speak. (209)472-0843 (1:208/216)

ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
Date: 11-30-93 12:15
From: Richard Quick
To: David Tiefenbrunn
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ

RQ> DT> At what power level does it become dangerous to
RQ> DT> draw spark with the pole?

RQ> This is a very good question. Very good. I routinely pull
RQ> spark off of my coils with a key, pipe, or other conductor.
DT> ...
RQ> Power arcs leaving the body and hitting the ground are very
RQ> dangerous, especially for those who are more shock
RQ> sensitive than myself. I do not experience "shocks" in these
RQ> instances, but do feel the RF burns. I have also had a few
RQ> RF burns from change, keys, etc. on my person, as well as
RQ> having lost all the magnetic strips on my bank and credit
RQ> cards. My brother lost a nice digital watch once.

RQ> But, if you know what you are doing, and the system is well
RQ> set up in proper tune, it is OK to take up to 5 kVA output
RQ> through a conductor to your person. But this is not
RQ> recommended for amateurs.

DT> Reminds me of one of my dad's T shirts:
DT> I am a professional. DON'T try this at home.
DT> You should get one :)

DT> It would seem that the important thing is to not
DT> allow a spark to jump directly to or from the body.

Yes I would tend to agree with this, especially at higher powers.
The charge density and amount of power alone can be dangerous,
despite the output of the coil being clean RF. I don't know if
the resolution on the tape is good enough to see but in the shot
where I am pulling a few feet of spark off the coil with a copper
pipe, there are some 6" - 8" sparks coming off my feet. Since I
am standing on an insulated platform, and my shoes socks are
sweaty, I only get a tingling sensation.

Another thing to caution about is being in series with a power
arc from the discharge terminal, even if the actual arc leaves a
conductor such as a pipe or what not. Again the charge density is
just too high on a big coil to make this safe. I have been placed
in an uncomfortable position or two where this has happened, and
the operator of the coil needs to have a cool head and be very
familiar with the controls. I wish I had these incidents recorded
on video tape.

When doing the million volts through the body trick, or other HV
RF experiments when in physical contact to the output, discharge
must be radiated or arced through the air, not to ground. Power
arcs to ground while in series with the circuit is "eye opening"
to say the least, and can make your fillings really sing.

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Date: 11-23-93 10:28
From: Dave Halliday
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
> DH> Geeez Richard - and I thought *I* had too much going on
> DH> at once what with my boat, woodworking shop, metal shop (
> DH> lathe, wirewelder and torches ), music studio,
> DH> homebrewing, BBS, computers and printing...

RQ> DH> This takes the cake <grin>

RQ>Isn't it funny how intelligence and imagination breeds havoc?

Havoc... Now *that's* a polite term for it <grin>

RQ>Mark Lawton (spel) sent me a post about all of his concurrent
>projects too. It seems we landed in a nice spot to exchange a
>few ideas and interests. This conference is not too crowded,
>yet several people end up with similar sets of hobbies and
>interests.

Great! I am looking to connect to a local source for FIDO just
for this conference...

RQ>BTW to keep somewhat on topic, I really hope your coiling
>efforts are moving along. I have tried to dump as much as
>possible in the last few days, and have spent several hours
>per day in organizing my thoughts and getting them out.

I sent you a status report a couple days ago - just getting stuff
together right now. I will be going to the Boeing surplus place
today and will see if they have anything of interest - they are
closed on Monday - they put all the new stuff out then so Tuesday
is the primo day to go there... TTYL - Dave �:-) 301-794-6496
(1:109/546)
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Date: 11-23-93 10:36
From: Dave Halliday
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
RQ> DH> Used to work for the public aquarium in Boston and we had
> DH> grounding problems like you wouldn't believe - I was

RQ>A few months back when our local sysop first added this
>conference, there was an thread on grounds and grounding that
>you just would not believe (well maybe you would), anyway, the
>misunderstandings and misconceptions about grounds and
>grounding, and the bizzare things that happen when equipment
>and systems are not properly grounded...

I can well imagine - I also did PA systems for bands for a while
and some of the perceptions about power and signal grounds were
amazing.

Not so much for their blind ignorance and lack of common sense
but for the fact that some of them were still alive <grin>

RQ>By reading the Colorado Springs Notes it is quite clear that
>Tesla struggled to get a good ground on site for his system
>and cited the local geology (sand & rock) as the source of his
>problem. He eventually had to run water 24 hours a day over
>his ground.

Interesting - the water table there is probably pretty low so
that would be a problem. In Seattle, the reverse is true - where
I live is fairly close to Lake Washington and the ground is
pretty wet all year round.

I will probably drive a couple lengths of copper pipe into the
earth for the coil ground - the ground for the house is a 6'
copper rod but from what you say, the more the merrier!

RQ>His control, or line frequency, ground was the water pipe.
>Tesla was capable of producing serious ground currents from
>the machine. Some of the effects were reported many miles
>away; sparks coming off the shoes of horses which caused
>the animals to spook, clouds of insects covered in St.Elmos
>fire, in addition to the locals getting sparks from their
>water taps.

Must have been fun to live near there <grin>

RQ>When he went on to Wardenclyff, he spent half of the tower
>construction cost on the well with 18" copper plated steel
>pipe driven into bedrock 50' below the water table. He did not
>intend to mess around.

Jeeezzz! I guess not!!! That is getting a bit serious!

Anyway, TTYL - Dave 301-794-6496 (1:109/546)

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Date: 11-23-93 10:38
From: Dave Halliday
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
RQ> Harry Goldman
> TCBA
> 3 Amy Lane
> Queensbury, NY 12804
> Tel: (518) 792-1003

RQ>Tell him I sent you!!!

Thanks! Will do 301-794-6496 (1:109/546)

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Date: 11-23-93 11:16
From: Dave Halliday
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
RQ> Primary coils

Me again... This is exactly the info I need! I was wondering
what would work best.

>primary coil should be large. I have seen lots of holdovers
>from the classic age of coil building who insist on 2-3 turn
>primaries and HUGE capacitors to achieve the proper frequency
>of operation in the tank circuit.

RQ>This is wrong.

RQ>A tank circuit with a small capacitor, and a large primary
>inductance, will reach down to the same frequencies of
>operation. A tank circuit of this design will use less power,
>and therefore require a smaller step up xfrmr. The capacitor
>will be smaller, which further reduces the cost of the system.

Makes a lot of sense! Also, because of the losses in the
capacitor, using a lower value will result in less loss...

RQ>So to give some advice to my friend Dave Halliday, who is
>building a 6" secondary coil sometime in the near future,
>plan on winding a primary coil from a conductor material that
>I have listed above, and use a conductor length of around 75
>feet. Your primary should end up about as wide as, or wider,
>than your secondary is tall.

Got it! I was thinking of using some 3/8ths refrigeration tubing
but since the surface area is important, I'll probably get a reel
of 3/4ths or 1/2" tubing ( gotta check on pricing first )

Also, I wasn't thinking about the length of the primary and I
only have about 20' of the small tubing.

I'll be going to Boeing today so they might have something there
too.

Again - many thanks for the info - I have a pretty good handle on
what is needed - like I said, probably building the capacitor
over the Thanksgiving weekend - I'll be closing the store then...

Trade some videos / photos once I get something to show.
301-794-6496 (1:109/546)

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Date: 11-20-93 18:24
From: Joseph Freivald
To: Richard Quick
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
For those of us who are wanna bees, What's a tesla coil, and why
does it get at least 10 posts per day? Just trying to catch up,
Joe 301-794-6496 (1:109/546)

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Date: 11-23-93 17:49
From: Dave Halliday
To: Joseph Freivald
Subj: 10KVA Tesla Coil
ﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄ
JF>For those of us who are wanna bees, What's a tesla coil, and
>why does it get at least 10 posts per day?

JF> Just trying to catch up,
> Joe

Hi Joe - the Tesla coil is basically a high-frequency resonant
air transformer - oscillator system. It was developed by a
wonderful genius / wildman Nikola Tesla ( 1856-1943 ) as a means
of generating very high voltage as well as power transmission.

Richard has a great two hour video tape of his work which he will
send to you for the following: ten bucks, a blank good quality
tape, and postage paid mailer

It is well worth it! His "big" coil is about 4' tall and fires
continuous bolts of lightning from nine to fifteen feet! This is
a point-to-point measure too so add in about 30% for the twists
of the arc!

I used to be into them when I was a teenager and had always
thought about getting back into it but the stuff he is working on
has convinced me! I will be working with a couple friends (
sharing work 'n money ) and we are starting work on parts of it
this thanksgiving holiday.

It is interesting too because the "classical" design for a tesla
coil is quite different from the actual best design. The
classical design goes for long thin coils ( maybe 30" by 3" dia.)
and just two or three turns of wire for the primary whereas the
actual best design calls for much shorter / fatter coils and lots
of primary turns ( 10 - 15 )

My friends and I have arrived on a basic design - 6" diameter and
30" long, fixed spark gap, 12kV neon sign transformer and
homemade capacitor. Richard mentioned that he once built one
just like this and he was able to get 5' bolts!

Anyway, the posts are well worth saving, send away for the video
tape too - it makes for fantastic viewing! 301-794-6496
(1:109/546)

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