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Hmm, what do I know about? lets
see ummm, How about Tesla coils and how to build one, how to stay
alive, and where to get parts. Never mind what to do with them
once they are built.
To start out you will
need one of two things, money or resources. I have a small amount
of both and have been able to build a nice coil and make nice
sparks. Firstly you need to know what one is and what it does.
A tesla coil is a transformer, it has a primary and a secondary.
The primary is really just a coil of fat wire or copper tube (it
has to be conductive, electricity needs to flow through it). This
coil can be either a flat spiral, an ascending helix, or a combination
that looks like a punch bowl or something like that. This thingy
is what produces large magnetic fields which make the secondary
go (or excite it). This coil does not need insulation on it, you
will not be touching it anyway and adjusting will be easier. I
prefer flat spirals and will deal with them only for right now.
In order to get the spiral right and keep it right you will need
a form or base, all tesla coil (T.C.from now on) components must
be made of an insulating material such as dry wood, pvc, lexan
or plastic. This form can be a flat sheet with holes drilled for
mounting the primary or a cross or "plus" design with
holes for mounting. I like the "plus" design and use
plastic wire ties for the mounting. be creative. Coil the tube
(what I use) or whatever into a spiral with about 1/4" spacing
between turns, this is not critical but should be less than 1"
for good results. The primary should have about 15 turns total
less can be used and more can be used but 15 is the number that
seems good for me. The dimensions for this coil's inner turn will
be about 2" more than the diameter of your secondary. This
is the primary more or less.Now on to the secondary.
The secondary is a tube
(insulated of course) which has lots and lots of thin wire wound
on it, it is where the big high voltage comes from when excited
by the primary. You can use cardboard (dried and coated with polyurethane),
pvc (easiest), or anything that is not a conductor, as a side
note black plastics may contain carbon, a conductor and should
be avoided. This tube goes in the center of the primary when complete.
The diameter and length of the tube are important factors here,
the diameter can be from 2" to about 12" but for a beginner's
coil one should choose something around 3-4". The length
of the tube should be about 5 times the diameter. Wire that is
used should be of the magnet/ transformer variety. I have taken
apart motors or other transformers to get the wire I needed. It
is easiest to buy it online or at a electrical supply shop. Wire
gauge can be from 32-22 or something like that, not too small,
not huge either. I am building a secondary right now with 24 gauge
plastic insulated wire, most people use the stuff with a shellac
coating and for a first coil I would too. The tube is wound with
the wire so that there are no kinks or knots or gaps, this looks
better and works better, only one layer of wire is needed and
should run the length of the tube. Estimated number of turns should
be around 1000 or so give or take a few hundred. Now mount this
thing in the center of your primary (but not permanently). Adjusting
the height of the secondary relative to the primary may be needed
during fine tuning.
The next part of the
system isn't really part of the tesla transformer, it is what
makes the TC work. For this you will need a few components that
are pre-made unless you know how to build them in which case you
shouldn't be reading this far (unless you are going to email me
and correct my mistakes) The heart of the system is a transformer,
not just any transformer. A high voltage step-up transformer.
This is what you just built only different. I find that it is
best to use a transformer form a neon sign or oil ignition transformer
from a furnace that runs on oil. These things can kill you and
me and animals and burn things and cause great harm. They should
not be used by little shits who want to break things and should
not be left where little shits are around. that said you can get
one of these transformers from a sign shop or a furnace place,
ask real nice and you may get a used one for free or a few bucks.
They cost about 100$ new so don't get screwed. Check Ebay, they
have them all of the time but they weigh about 30 pounds so figure
that into your cost if you need it shipped. I use neon transformers,
they take the 120 volts from the wall outlet and make it about
15,000 volts. You can use anything between 9,000 and 15,000 volts
for a nice coil, there is another rating on these besides voltage
and that is amperage, this will range from about 23ma to 90 ma
(ma means mili. amp) anything in this range will do just fine,
the bigger the better for the end result though. (remember to
start small). Now connect this transformer to a Capacitor. The
capacitor is an energy storage device, it is just a few sheets
of insulation with a few sheets of conductor in between them.
I won't go into how this works here and now but it is magic. I
build my own caps(capacitors) I use sheets of plate glass and
sheets of aluminum flashing stacked with the edges of the aluminum
about 2" from the edge of the glass. The plates are connected
in a manner such that the even plates of flashing are all connected
and the odd plates are all connected. (I use about 12 plates total)
Thickness of the glass will depend on the amount of voltage used
and the number of plates that you use. The thicker glass is what
I use because it is less likely to puncture under stress from
the high voltage. Anywhere from 1/16" to 1/4" is acceptable,
the thicker the glass the more plates you will require. This whole
thing can be submerged in oil to prevent arcing over. (any cheap
non-detergent motor oil is fine) Better than this whole thing
though would be to buy a bunch of small capacitors and wire them
up for higher voltage and capacitance. There will be a link to
a page below that sells the best (they are referred to as a MMC
or multi. mini. cap.) A good cap can be made with beer bottles
too, the same link will provide detailed instructions on how to
build one (called a bucket cap) So you have your cap made now
right??? remember high voltage will arc about 2" or more
so clearance between wires, coils and caps and transformers should
be at least 4". Clearance between any of these things while
running and you should be ten feet or more. Almost lastly we need
a gap or spark gap, one can be seen on my tesla coil page, it
is a few copper sections about 2" long mounted in a pvc tube
with a fan blowing down it from the other end for cooling. The
spacing should be adjustable and small (mine are less than 1"
total ) Other people use simpler gaps made from 2 metal bolts
set apart on an insulating platform, others make elaborate rotary
gaps with motors and spinning disks with electrodes on them, the
copper pipe/ pvc is a good compromise between performance and
simplicity. This completes the thingy that makes the TC go. I
will tell you how to wire it next.
To wire the thing up
you will need some wire, high voltage wire is nice to use but
anything will do as long as it is thick so you don't lose much
power. Fat radio shack speaker wire is good and so is 12 gauge
house wire. Even though it is insulated it needs to stay away
from everything and especially you. Not many things are really
insulators at high voltage, they are Merely setbacks and electricity
will find a way to get what it wants and that is ground, through
you, through your pet, or through your buddy. So, use wire, keep
it away from everything, keep it short where possible. connect
one terminal of your neon (or whatever) transformer to one side
of your cap, connect the other side of your cap to your copper
primary (the inside turn). Connect the other terminal of your
neon transformer to one side of your gap. Connect the other side
of your gap to a flexible wire with a clip on the end and connect
the clip to your primary spiral at the outermost turn. This a
tuning point where the primary is adjusted referred to as the
tap. Next connect the bottom wire of your secondary to a rod pounded
into the ground. This is your ground and should be wired as short
as possible through heavy wire. If you cannot do this, it is possible
to place a 4X4 sheet of chicken wire under the coil (isolated
from anything and everything) and connect the bottom of the coil
to this. Four by four is just a suggestion, more or less may be
fine. And the other end (top) of your secondary is where the action
is, this is the output terminal, experiment with placing objects
on it to see what works best. I have some TC's that don't need
any output terminal and I have others that work with a foil covered
tennis ball or pie pan. The rule is that it has to be conductive.
Experiment here too.
Now that your coil is
built and wired up, stand far away and plug in your neon sign
transformer and let the thing fly, you will get great loud sparks
from your gap, your capacitor will hiss to life, and with any
luck you will see sparks coming from your output terminal. Now
unplug it, take a long pvc pipe (a foot or two) with a heavy wire
in the end and short out your capacitor by connecting both sides
together. Adjust your primary tap in our out a turn or so and
see what happens next time you plug it in, if the spark is bigger
good, if it is smaller go back and re-adjust the tap through trial
and error. If nothing happens when you plug in the transformer
go and adjust the gap closer together after turning off the power.
Plug it in again and see if it sparks then. Setting the gap too
close will ruin the coil's performance and may damage your transformer,
setting it too far apart will cause either nothing to happen or
your capacitor will be stressed along with your transformer. It
is all a balancing act from here on out. Do not run the coil for
more than a few seconds at a time until it is in tune, then only
a few minutes. And lastly, which should be firstly...
Safety. High voltage
will make you dead quick, it won't feel good, you won't like it,
and your friends will call you stupid at your funeral. At the
very least you will get a nasty shock or burn from touching anything
on the coil. Stay away from the output terminal too, the frequency
of the voltage may be high but will still hurt you. Safety is
of utmost importance. If you get dead it isn't my fault, you have
been warned.
This has been a brief
introduction to what a tesla coil is and how to make one, for
further information follow my links below, they cover things in
more depth and all of your questions will be answered. TC's are
fun to build use and observe, start small, familiarize yourself
with the principals involved, look at other designs and follow
their guidelines. You probably won't have any problems. If you
do have problems one of my links below is a discussion group and
will provide more than you ever need to know about coiling.
Tesla
list this site is for
the email list and asso. archives about tesla coils
The
geek group These guys are cool too, they exist to educate
(and sell stuff you need)
TCBOR
The tesla coil builders
of Richmond