Help on Tesla Coil design

Hi everyone! Ok, first time posting, sorry in advance if im breaking any rules. Anyway, I am building a tesla coil and I have lots of questions before I spend anymore time and money. If y'all wouldn't mind checking out my specks and telling me If im doing anything wrong I would greatly greatly greatly appreciate it. Secondary: 4" sch 40 PVC (4.5" diameter) 20 inch winding height with ~1200 turns of 26awg. Primary: 15 turns =BC" copper tubing =BC" spacing. Power supply: 2 12kv NSTs @ 30 ma each in parallel =3D 12kv @ 60ma Capcitor bank: sort of complicated I need ( I think ) 18nF so (sorry about the lack of a picture) this is what I think I should do. Each cap is 5000pF, and 3kV. 4 caps in parallel and two caps in series should give me 12kv and 10nF. I need roughly double this so, two of these groups will be set up parallel to each other giving me 20nF at

12kV. In order to double the voltage rating I will put two of these groups in series. This should give me 20nf @ 24kv. I think I have this wrong so please help! Oh yeah, each cap has a 1.3mega OHM 1/2watt resistor across it. Spark gap is 7 X =BE" copper tubing on a section of =BE" HDPE. Two squirrel fans for quenching. I need to design a NST protection circuit. I'm sure ill just copy someone else's. How long can I make the secondary after the end of the windings? Can I have a 9 inch gap between the windings and the toroid? (I hacnt decided on the top toroid yet. Thanks again, i really want to get this thing up and running,.
Reply to
ChrisGEdwards
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ok, im an idiot. forget what i said about the capacitor bank. the cap configuration i mentioned would never work. i only have about 65 caps. any ideas?

Reply to
ChrisGEdwards
12kV. In order to double the voltage rating I will put two of these groups in series. This should give me 20nf @ 24kv. I think I have this wrong so please help! Oh yeah, each cap has a 1.3mega OHM 1/2watt resistor across it. Spark gap is 7 X ¾" copper tubing on a section of ¾" HDPE. Two squirrel fans for quenching. I need to design a NST protection circuit. I'm sure ill just copy someone else's. How long can I make the secondary after the end of the windings? Can I have a 9 inch gap between the windings and the toroid? (I hacnt decided on the top toroid yet. Thanks again, i really want to get this thing up and running,.
Reply to
amdx
12kV. In order to double the voltage rating I will put two of these groups in series. This should give me 20nf @ 24kv. I think I have this wrong so please help! Oh yeah, each cap has a 1.3mega OHM 1/2watt resistor across it. Spark gap is 7 X ¾" copper tubing on a section of ¾" HDPE. Two squirrel fans for quenching. I need to design a NST protection circuit. I'm sure ill just copy someone else's. How long can I make the secondary after the end of the windings? Can I have a 9 inch gap between the windings and the toroid? (I hacnt decided on the top toroid yet. Thanks again, i really want to get this thing up and running,.

I suggest you go to

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and sign up for the Tesla coil mailing list. There is lots of archived info. The group is very helpful with several very knowledgeable people, I warn you this is a very busy group. Mike

Reply to
amdx

Hmmm - I don't think you are using a flux capacitor - it won't work.

Hardy

Reply to
HardySpicer

Subscribe to and ask your questions in alt.energy.high-voltage

It is full of Tesla folk.

Reply to
The Great Attractor

no such newsgroup. Have a different name?

Reply to
West

Hi,

It sounds like you have a pretty good start.

You probably don't need quite that much capacitance. My TC has a single string of capacitors in series to get the required voltage rating, but the total capacitance is only several hundred pF. You could get away with 6 pairs in series to get 1.66 nF at 18 kV; or 6 triplets in series for 2.5 nF at 18 kV. The resistance across each pair of capacitors (or each triplet) should be higher than 1.3 Meg, more like 10 MegOhm at 1 Watt each. You'd have ended up smoking those

1/4 watt 1/3 Meg resistors.

When you power it up for the first time, don't double up on the NSTs. Get it tuned up with a single NST, then double up on the primary current.

As for the HV end, keep the #26 gauge end lead as close to the cap/ toroid as possible. My coil only has a bare wire off the end of the winding.

Good Luck Tom P.

Reply to
tlbs101

Bullshit...

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Reply to
ChairmanOfTheBored

Unless you have high voltage (long path length resistors) the spark may easily track across the outside of the resistor.

Look up the pupman forum for Tesla coil enthusiasts - lots of good info and they have a basic and advanced forums.

I've had better results with a spark gap made from stubs of 1" CU tube with end caps, than parallel copper tubing. Likewise magnetic gaps and compressed air gaps and rotary gaps.

Protection circuits: chokes and safety spark gap(s). Ferrite chokes will work but the wire insulation has to be very good because each turn of wire around a ferrite has a lot of inductance relative to air core.

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