Tabletop Tesla Coil by Mr. Apol
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Step 1: The frame

The frame of the tabletop Tesla is made entirely of half-inch (12.7 mm) PVC pipe. There's no point giving you exact dimensions of the stringers and risers because they depend on how big your secondary coil is. You can scale the frame up or down as you wish. I used a 12 inch long cardboard tube for mine, making the footprint of my coil 14 inches by 11.25 inches.

Study the pictures and you will see how the frame is made. The configuration as made requires the following joints:

(4) 90 degree elbows;
(8) "T" joints
(2) end caps

All the rest is straight half-inch tubing, cut to length. NO CEMENT WAS USED TO JOIN THE PARTS and none should be used. The friction fit of the tubing is reasonably strong, and leaving the joints unglued allows you to take the frame apart to work on the coil, make adjustments or repairs, etc.

The center uprights consist of three T joints each, stacked vertically. Short lengths of tubing connect these. If you make a bigger coil these length will have to be adjusted accordingly.

The cross piece that runs underneath and parallel to the secondary coil has to be drilled for the primary supports. Find the center point of the cross piece and drill two holes so that the primary form in centered on the secondary. Again, I can't tell you exactly where, because it depends on what you use for your coil forms. But center it and it will be fine. See the page on the Primary for more details of the mounting method.

The secondary is supported by plumbing caps and tubing adapters inserted into the cardboard tube. The tube I used is 1.75 inches in diameter (it's a thick-walled cardboard paper towel tube). I had to experiment at the home center to find off the shelf PVC plumbing pieces that would fit, but I found ones that slip in closely. Again, no glue was used. You want to be able to remove the secondary for maintenance or replacement.

In the two topmost T joints insert plugs to support the brass terminal posts. These can be anything non-conductive--cork, rubber, etc. I found wine corks fit nicely. Push them down equally on each side until they are level with the top edge of the secondary form. Above them fit a length of PVC tubing. Exact height is not too important; they should be tall enough to keep the terminals away from the active coils to avoid arcing. Mine are four inches tall each.

Drill 3/16ths holes in the center of two PVC pipe caps for the terminals. Drill small holes--about 1/8th inch--in the support tubes opposite the ends of the secondary coil to feed the secondary's wires through. See the step about the Terminals for final connections.
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iungerich1 says: Apr 22, 2013. 10:00 AM
hello i am thinking about doing this project but i have a few questions
first i am thinking about buying this transformer http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=271193170693&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en
at 12 kv and 30 ma i think it will work now all i really care about is the large hi voltage spark so can i just have one of the terminals attached with wire to a large stick i will hold and short out the other terminal? i guss what i am asking is the voltage high enough to get any sparks and if so how big do you thunk i can get them?
Mr. Apol (author) says: Apr 22, 2013. 10:05 AM
That transformer will undoubtedly power a Tesla coil and draw arcs as well. Please be very careful!.

Paul
iungerich1 says: Apr 22, 2013. 10:01 AM
sorry thunk was supposed to be think lol
smehta6 says: Jan 4, 2013. 11:20 AM
would this work:: http://www.ebay.com/itm/Neon-Transformer-Tesla-Coil-Jacobs-Ladder-6000v-60-ma-science-project-idea-/281046283060?pt=BI_Circuit_Breakers_Transformers&hash=item416fa9f334
Mr. Apol (author) says: Jan 14, 2013. 7:19 PM
No, it will not work. Look at the label; it says there is secondary ground fault protection. That will prevent a spark gap working.

PBT
Mr. Apol (author) says: Jan 4, 2013. 8:07 PM
Yes, it would work fine.

PBT
smehta6 says: Jan 14, 2013. 7:03 PM
http://www.ebay.ca/itm/Neon-Sign-Transformer-UL-Power-Supply-/160954403253?pt=BI_Circuit_Breakers_Transformers&hash=item2579a149b5&_uhb=1#ht_638wt_1271 will this work
smehta6 says: Jan 2, 2013. 6:31 PM
what is the most cheapsed power supplies because i am using this for a project and i need only for a little bit?
Mr. Apol (author) says: Jan 3, 2013. 3:11 AM
That's hard to say, because it all depends on what you can find. The simplest and most suitable power supply would be a neon sign transformer (without Ground Fault Interrupt circuitry), although other possible sources include oil burner transformers, induction coils, car ignition coils, etc.
smehta6 says: Jan 2, 2013. 6:15 PM
do you connect the one of the secondary coil wire to the terminal or both?
Mr. Apol (author) says: Jan 3, 2013. 3:08 AM
One end of the secondary coil is connected to an earth ground, and the other end connects to the top terminal (metal sphere, toroid, or whatever). In some cases the bottom end of the secondary can be connected to the bottom end of the primary, creating an autotransformer, or Oudin coil configuration.
smehta6 says: Dec 11, 2012. 7:20 AM
and will the The Capacitors work and thx for the reply
Mr. Apol (author) says: Dec 11, 2012. 1:33 PM
They will, but you have to adjust the capacitance to fit your coil. Other caps will work as well, and may be easier to find and cheaper.
smehta6 says: Dec 5, 2012. 11:54 AM
nice work
would http://www.instructables.com/id/How-to-build-a-Tesla-Coil/?ALLSTEPS spark gap work on this teasla coil? please answer?
Mr. Apol (author) says: Dec 5, 2012. 1:43 PM
A simple two piece spark will work, yes. It isn't very efficient though, as it overheats quickly, which cuts down on coil output. Multiple spark gaps are better, and pressurized spark gaps are better still.

PBT
al 01 says: Dec 1, 2012. 11:20 PM
nice work,
Can it be reduced in size?
Mr. Apol (author) says: Dec 2, 2012. 5:53 AM
Sure, to a point. You will have to adjust your components for a change in resonance that will occur if you change the size of your coil. (The coil in this Instructable isn't very big to start with, BTW).

PBT
CaptainMunz says: Jun 1, 2012. 10:06 AM
Would it work if I used the frame and coils with the power source being this AA powered circuit?

http://www.instructables.com/id/AA-Battery-Powered-Tesla-Coil/
Mr. Apol (author) says: Jun 1, 2012. 5:11 PM
I don't think you'll get enough power out of two AA batteries to power a Tesla coil for more than a few seconds--at the very most. The device described is just a TV flyback transformer (whose output is DC). If you ran the flyback off house current, you would get somewhere, but two AAs just aren't potent enough.

PBT
disappearingshadow says: Apr 23, 2012. 4:39 PM
http://www.ebay.ca/itm/LOW-GLOW-NEON-9500-VOLT-TRANSFORMER-FITS-LOWGLOW-AND-MANY-OTHER-NEON-BRANDS-/380430895286?pt=Motors_Car_Truck_Parts_Accessories&hash=item589372c8b6
I was thinking of getting this one. Do you think it would work with this project?
Mr. Apol (author) says: Apr 23, 2012. 7:47 PM
It will definitely not work. These Low-glow modules are solid state power supplies with Ground Fault Interrupt protection. This means they will not power a spark gap at all. Do not use these for Tesla coil power supplies.

Paul
disappearingshadow says: Apr 23, 2012. 7:55 PM
Okay thanks :D how about this one?
http://www.ebay.ca/itm/New-10kv-30mA-Neon-Power-Supply-Neon-Transformer-UL-Series-A410EL-/150798592048?pt=LH_DefaultDomain_0&hash=item231c4be830
Mr. Apol (author) says: Apr 24, 2012. 3:14 AM
Nope. See the mention in the description that it has "open circuit protection?" That's GFI.

You need something like this: http://www.ebay.com/itm/NEON-TRANSFORMER-7-500-VOLTS-For-Neon-Signs-Jacobs-Ladder-or-Tesla-Coil-/330719105373?pt=BI_Circuit_Breakers_Transformers&hash=item4d0065115d#ht_507wt_934


Paul
disappearingshadow says: Apr 24, 2012. 7:17 AM
I am having a lot of trouble trying to find one in Canada. I don't supposed you know any good sites.
Mr. Apol (author) says: Apr 24, 2012. 3:25 PM
Try the phone directory for Sign Shops, Neon Signs, etc. A lot of shops are changing over to solid state GFI transformers and getting rid of the old fashioned iron-brick type of transformer. You may be able to buy one from them. They might even give them away, just to get rid of them. You can also try oil burner ignition transformers (OBITs, they're called). Avoid GFI units again. You can also build power supplies based on automobile ignition coils.

Good luck. Try in person where you live, or any nearby city.

Paul
disappearingshadow says: Apr 24, 2012. 8:23 PM
I went to a neon sigh place and they gave me Ann allanson power pak it has 35 ma 7200v complies with secondary ground fault protection requirements please tell me it works
Mr. Apol (author) says: Apr 25, 2012. 3:22 AM
Does it look like this?

http://www.google.com/products/catalog?q=Allanson+power+pak&um=1&ie=UTF-8&tbm=shop&cid=9228341418964618920&sa=X&ei=3c2XT7LeHaX02QWH3sGIBw&ved=0CEQQ8wIwAg

If so, it won't work. It has GFI protection.

Here's a simple rule of thumb about NSTs. If it's big and heavy, it will probably work in a Tesla coil. If it's small and light, it's solid state and has GFI.

Here's a listing on eBay Canada for a non GFI unit:

http://www.ebay.ca/itm/15-000-Volt-Allanson-Neon-Sign-Transformer-Lighting-Unit-Non-GFI-Tesla-Coil-/120900954333?pt=BI_Circuit_Breakers_Transformers&hash=item1c264228dd#ht_500wt_950

and

http://www.ebay.ca/itm/neon-sign-transformer-9-000-volts-france-ground-fault-/300699999724?pt=BI_Circuit_Breakers_Transformers&hash=item46031dddec#ht_500wt_950

more are listed if you search for "neon transformer."

Paul
The MadScientist says: Apr 6, 2012. 2:17 AM
What's the current output of your transformer?
Mr. Apol (author) says: Apr 6, 2012. 3:10 AM
30 mA at 7,500 volts. That's the transformer I use most often. The coil works fine with any common NST.

Paul
The MadScientist says: Apr 16, 2012. 1:29 AM
Cheers
somebody12345 says: Dec 24, 2011. 7:37 AM
I have the exact same cardboard tube.
teslacoilguitaramp,helpmeplz says: Mar 3, 2011. 7:42 PM
sorry to burst you bubble, but i think that is a fancy spark gap not a Tesla coil. but with that design should get some nice arcs.
Mr. Apol (author) says: Mar 4, 2011. 3:14 AM
This is a Tesla coil with a horizontal secondary and bipolar terminals. Commonly Tesla coils are made upright, but the horizontal style is indeed a Tesla coil also.

PBT
teslacoilguitaramp,helpmeplz says: Mar 3, 2011. 7:53 PM
i wanted to know how you connected the capacitors? wich is how i found this, i need some capacitors, and i want to play it safe and make 2 or three large ones that could hndle the output almost alone but for safety and emergency measures..
Mr. Apol (author) says: Mar 4, 2011. 3:10 AM
For a basic Tesla coil circuit diagram, see:

http://home.gallatinriver.net/mhammer/coil.htm

This is the circuit I use, though I don't use a safety gap in such a small coil.


Paul
jimmydean123 says: Feb 26, 2011. 8:32 AM
i have everything wired up correctly, but my tesla still won't work. The spark gap won't spark, and we know it isn't the transformer because it had enough power to burn out my multimeter. Any suggestions?
Mr. Apol (author) says: Feb 26, 2011. 10:29 AM
I need more information.

What is your capacitor? Have you tested it for correct function?

How wide is your spark gap? A too wide gap will prevent the coil from working.

How is your secondary wound? How big is it? What gauge of wire?

How is your primary wound? What gauge? How many turns? Is it wound the same way as the secondary, or in the opposite direction? Opposite winding will keep the coil from working properly.

How big is your transformer (how many volts, how many amps)? What kind is it? If it is a modern sign transformer it will have Ground Fault Interrupt (GFI), which prevents it from working in a spark gap circuit. This, I suspect, may be your problem.

Paul
jimmydean123 says: Feb 26, 2011. 12:30 PM
My capacitor is made up of 8 peroxide bottles with a monster can inside each. I have not tested it but i can hear it when i turn it on.
My spark gap is set up so each knob is extremely close to touching but is not touching.
My secondary is 24 gauge magnet wire gauge wire with approximately 443 windings.
My primary is 12 gauge wire with 5 windings. I think it might be in the opposite direction.
My transformer is a Pro Series Low Glow neon sign transformer. The input is 12-15VDC at 5 amps (max.). The output is 9500V; the output amperage is 30 mA. It also has an 8 amp fuse.
Mr. Apol (author) says: Feb 26, 2011. 7:06 PM
I believe your transformer has GFI. It will not power a Tesla coil because the GFI prevents the spark gap from firing. You need an old fashioned neon sign transformer or an oil burner ignition transformer.

Paul
jimmydean123 says: Feb 27, 2011. 9:54 AM
thanks for the advice but i guess i'm gonna have to buy a new (or old i guess) transformer anyway becausewhile trying to override the GFI i shorted out the transformer any suggestions on a low cost transformer that would fit the bill
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