Tesla coil problems.

[Ruben Schoonbaert]

Hold your horses, we'll get to that.


The calculator I just provided for you is for a pancake coil. You can always change it later if it seems necessary, though you'll need to tap ("tune") it differently if you do.

Start by constructing the coil as described so far with the correct topload and primary coil. I recommend using bare copper wire for the primary - it will make it easier to tune later on. Give it 20 or so turns if you can. Take photos and post them here so I can see how things turned out, and then we can go from there.

So my wire is multible strands... but i found some PE wire that has a single copper core.
It has a core of 2mm in diameter and its 4mm in total with the insulation included.

 

[DerStrom8]

So my wire is multible strands... but i found some PE wire that has a single copper core.
It has a core of 2mm in diameter and its 4mm in total with the insulation included.

Ok, that sounds better. Insulation diameter doesn't matter, just the actual wire diameter.

Using the calculator, put in 0.2 inches for "S" (spacing between turns), 0.0787 inches for "W" (wire diameter), 2 inches for "D" (inner winding diameter), and 15.4 (microhenries) for "L" (desired primary coil inductance). The resulting "N" will tell you how many turns you need (you will want more so you have room to "tap" the coil in order to tune it) and "Do" tells you the outer diameter of the primary coil.

 

[Ruben Schoonbaert]

Ok, that sounds better. Insulation diameter doesn't matter, just the actual wire diameter.

Using the calculator, put in 0.2 inches for "S" (spacing between turns), 0.0787 inches for "W" (wire diameter), 2 inches for "D" (inner winding diameter), and 15.4 (microhenries) for "L" (desired primary coil inductance). The resulting "N" will tell you how many turns you need (you will want more so you have room to "tap" the coil in order to tune it) and "Do" tells you the outer diameter of the primary coil.

11.32 windings so i guess ill make 12 windings.

 

[DerStrom8]

11.32 windings so i guess ill make 12 windings.

11.32 windings sounds correct. That being said, you should allow quite a bit extra, just in case. I suggest using at least 15 turns. This gives you plenty of room in case our calculations were off slightly. By tapping the primary coil in different places you can hone in on the exact frequency to match that of the secondary coil.

 

[Ruben Schoonbaert]

11.32 windings sounds correct. That being said, you should allow quite a bit extra, just in case. I suggest using at least 15 turns. This gives you plenty of room in case our calculations were off slightly. By tapping the primary coil in different places you can hone in on the exact frequency to match that of the secondary coil.

Found this template of a spiral that has 0.5cm between the turns, would this work?

 

[DerStrom8]

Found this template of a spiral that has 0.5cm between the turns, would this work?

Put it in the calculator. I gave it to you for a reason

Just remember the dimensions in the calculator are in inches, not centimeters. You'll have to convert from one to the other. Also remember "S" is the spacing between turns, not the center-to-center distance between turns. You'll have to make sure you use the wire diameter to calculate the spacing between the turns (look at the graphic in the calculator for clarification).

All that being said, 0.5 cm is pretty close to the 0.2 inches (0.508 cm) I used in my calculations, so I don't expect much of a difference.

 

[Ruben Schoonbaert]

Put it in the calculator. I gave it to you for a reason

Just remember the dimensions in the calculator are in inches, not centimeters. You'll have to convert from one to the other. Also remember "S" is the spacing between turns, not the center-to-center distance between turns. You'll have to make sure you use the wire diameter to calculate the spacing between the turns (look at the graphic in the calculator for clarification).

All that being said, 0.5 cm is pretty close to the 0.2 inches (0.508 cm) I used in my calculations, so I don't expect much of a difference.

So apparently 4mm wire is almost impossible to bend into the disired shape, so i bought some (core):1.5mm wire wich is mutch easier to bend.

 

[Ruben Schoonbaert]

So apparently 4mm wire is almost impossible to bend into the disired shape, so i bought some (core):1.5mm wire wich is mutch easier to bend.

So i think theres a fault in my calculations because i'm getting an error

 

[DerStrom8]

So i think theres a fault in my calculations because i'm getting an error

Could you be more specific please? Which calculations? What error? Screenshots would be helpful here.

 

[Ruben Schoonbaert]

Could you be more specific please? Which calculations? What error? Screenshots would be helpful here.

So i filled in 2 for S
0.039370 for W
2 for D
and 15.4 for L
But i am not getting an "N"

 

[DerStrom8]

So i filled in 2 for S
0.039370 for W
2 for D
and 15.4 for L
But i am not getting an "N"

Your spacing and wire diameter is 2 inches???

As I said several times, the measurements in that calculator are in inches, not millimeters, so you need to convert the units before putting them into the calculator.

 

[Ruben Schoonbaert]

Your spacing and wire diameter is 2 inches???

As I said several times, the measurements in that calculator are in inches, not millimeters, so you need to convert the units before putting them into the calculator.

Oh, Damn imperial systhem got me again.
So its 11.45windings

 

[Ruben Schoonbaert]

Oh, Damn imperial systhem got me again.
So its 11.45windings

 

[DerStrom8]

Looking good! You didn't leave a whole lot of extra windings for tuning though. I would have recommended at least 15 turns. Actually, I think I did at one point in this thread. Oh well, let's just hope you don't need the extra.

Ok, on to the driving circuitry. I know how eager you are to discuss this

A LOPT (line output transformer) like the one you're using has a high voltage diode built into it, so the high voltage output you have is half-wave rectified DC. This means that, unlike AC Tesla coils which charge the cap ever half mains cycle and discharge every other half, your coil will charge the capacitor up until the voltage is high enough to jump the spark gap. When it does, it dumps all of the energy from the capacitor into the primary coil and generates that LC oscillation we talked about earlier. Because your capacitor will charge until the voltage is high enough to jump the spark gap, the spark gap actually acts as a timing device. You will have to play with your spark gap distance a little bit until you get a satisfying output. This will have to be done in conjunction with the regular tuning. Are you familiar with the process of tuning a Tesla coil?

 

[Ruben Schoonbaert]

Are you familiar with the process of tuning a Tesla coil?

I am... also i wanted to make more windings but i ran out of wire :I.
Do you think the tesla coil will have enough power to ionize air ?

 

[DerStrom8]

I am... also i wanted to make more windings but i ran out of wire :I.
Do you think the tesla coil will have enough power to ionize air ?

It's impossible to say if you don't try it. Go ahead and fire it up, and try tuning and adjusting the spark gap. See what you get at this point. You may need a breakout point on the topload.

 

[Ruben Schoonbaert]

It's impossible to say if you don't try it. Go ahead and fire it up, and try tuning and adjusting the spark gap. See what you get at this point. You may need a breakout point on the topload.

I tested it and i am getting mutch better results.
It does not seem to be able to ionize air tho.
Ill try to upload a video of it in action to youtube and i will link it so you can see for yourself if any kind of improvement can be made.

 

[Ruben Schoonbaert]

Ok, it took a while to uptimize the coil but i have reached a point where i am happy with the results...
its capable of lighting fluorescent light bulbs and neon lamps. ects.
its not capable of ionising air on its own but it does jump to metal objects that are verry near.
Anyways, i really want to thank you for helping me trough this procces it really means a lot.

 

[DerStrom8]

Greetings Ruben,

I am happy to hear that there have been improvements to the design. I do still think that it should be possible to ionize air, though the coil is relatively large for a LOPT. Do you know how much current the transformer is supplying to the arc? You may be able to get significantly better results using an old style NST.

Could you post a video of just the LOPT running (and arcing)?

Regards,
Matt

 

[Ruben Schoonbaert]

Greetings Ruben,

I am happy to hear that there have been improvements to the design. I do still think that it should be possible to ionize air, though the coil is relatively large for a LOPT. Do you know how much current the transformer is supplying to the arc? You may be able to get significantly better results using an old style NST.

Could you post a video of just the LOPT running (and arcing)?

Regards,
Matt

I tried to get my hands on a neon sign transformer but i wasent able to find one, I have however ordered a ZVS module for my flyback witch will arive in a week or so.
(also what do you mean with LOPT?)