Tesla Coil Build Thread

[USAbro]

Well I've burned up my flyback and am trying to wire a new one using the core, but most tutorial videos don't show well, and most show a 4 wire input, although I was just using two.
Any help?

 

[upaa27]

Wind a lot of turns. You need to minimize loss and prevent core saturation. Vin/Vout=Primary turns:secondary turns. Be sure to add more because you will have loss.

 

[nospin]

Well I've burned up my flyback and am trying to wire a new one using the core, but most tutorial videos don't show well, and most show a 4 wire input, although I was just using two.
Any help?

On your flyback

is it the primary or secondary thats open?

 

[The Lightning Stalker]

Are you saying you are attempting to wind a
new secondary on the flyback? I don't
think it will be able to charge the tank
caps without HV diodes. AC flybacks are
nice for other things, though if you can
get one wound properly. Here is a good
video explaining one way it can be done.

 

[DashApple]

I used the core from a dead flyback to make a AC one ( was kinda rushed ) , I just used paper and oil as the insulation , Im not sure on number of secondary turns but I ended up with 10 layers of 0.2mm wire separated by 2 layers of paper and oil , voltage is to low for anything other than arcs or multipliers

I did run it for 9 minuets non stop at 40V supply with a ZVS : D

https://www.youtube.com/watch?v=y-hcZ2NZccc&index=153&list=UUvjDVNxRU2DInDMQQw_iYJA

 

[USAbro]

I've watched that video before but it doesn't explain the primary. Why is the voltage too low? If it makes almost 4 inch white arcs, that seems like plenty of power to me.

Anyways, here are two pictures of my current tesla coil I'm working with. Do you think it will work?
The board in the image is 12x12 with six turns on the primary. The secondary is 28 AWG wire 508 feet wound on 2 inch pvc pipe.

Thanks for the help

-USAbro

 

[upaa27]

I've watched that video before but it doesn't explain the primary. Why is the voltage too low? If it makes almost 4 inch white arcs, that seems like plenty of power to me.

Anyways, here are two pictures of my current tesla coil I'm working with. Do you think it will work?
The board in the image is 12x12 with six turns on the primary. The secondary is 28 AWG wire 508 feet wound on 2 inch pvc pipe.

Thanks for the help

-USAbro

USAbro everything you wound is fine. You just need to fix the tank cap and rewind the flyback.

Step one: do the equation I already gave you and give yourself at least 4 kv LOSSES INCLUDED

Next wind thin wire for the secondary. Make sure you keep track of the way it is going and turns. So if you need a 5:10 ratio DONT wind 5 turns on the primary and 10 turns on the secondary wind 500:1000 turns. That is with a hypothetically 100% efficient transformer so obviously you need more turns on the secondary to achieve desired output. The more the better.

3rd when winding the primary make sure you wind the opposite direction.

Done. Not to hard eh?

 

[USAbro]

Wait I'm confused. Are you saying my Tesla coil windings are done right?

About the flyback. I am winding 500 turns for the secondary of 28 AWG wire and 12 turns of 14 AWG wire for the primary. One piece of wire for the primary. Will this work with the ballast?

 

[The Lightning Stalker]

I've watched that video before but it doesn't explain the primary.

The primary is a pair of 5 turn windings
connected in series, from the looks of it,
although I would use 15 turns.

How to build a ZVS driver

Why is the voltage too low? If it makes almost 4 inch white arcs, that seems like plenty of power to me.

Plenty of power, yes. But again, you
can't power a Tesla coil with it. There is
no way. The frequency is too high. The
tank cap will act like a dead short and/or
the TC primary reactance will eat all the
power. Does anyone else want to see
upaa27's coil? It must be really cool.

Anyways, here are two pictures of my current tesla coil I'm working with. Do you think it will work?
The board in the image is 12x12 with six turns on the primary. The secondary is 28 AWG wire 508 feet wound on 2 inch pvc pipe.

It looks fine, though the pics are small
and it's hard to make much out. Did you
coat the secondary windings? Is the
primary insulated? Where are you going to
put the tap?

 

[USAbro]

The secondary has spar urethane painted on. I've wire it and it works with the flyback, just 1 cm arcs and the flyback puts out almost four inch ones. The primary is insulated. I will be using aluminum tape sheet capacitors with plastic from storage boxes in between.

Since right now I can't afford an NST, then what should I use? Right now, at 9:49 I'm winding my secondary on the flyback, already at 340 turns on my 3rd layer. Probably going for 5 layers.

I don't understand what you mean by "tap".

Also, why use two coils in series for the primary, instead of just one bigger one? It looks like he center taped it but I don't even know what center tap means, and how I'd do that for mine and wire it to the ballast.

Before it burned out, when I powered on the flyback with the leyden jars in parallel with one flyback lead and then connect to the other, it seemed fine. It made a white blue sparking and a loud buzzing, and the closer the spark gap the higher pitch the noise was and vice versa.

 

[The Lightning Stalker]

The secondary has spar urethane painted on. I've wire it and it works with the flyback, just 1 cm arcs and the flyback puts out almost four inch ones. The primary is insulated. I will be using aluminum tape sheet capacitors with plastic from storage boxes in between.

The secondary sounds pretty good, then.
The primary should ideally be more like 15
turns if you can.

Since right now I can't afford an NST, then what should I use? Right now, at 9:49 I'm winding my secondary on the flyback, already at 340 turns on my 3rd layer. Probably going for 5 layers.

Just keep going on it then. That will be
great fun if you can get it going, it just
won't run a Tesla coil. For that, you can
use another DC flyback, or an ignition
coil, or something else with a lower
frequency.

I don't understand what you mean by "tap".

Ahh, well that means you have not yet
learned how to properly tune a Tesla coil.
Here is a relevant quote from a great site
I found using Google.

I had to tune the Primary Coil’s frequency to match the Secondary Coil’s, so that they are in resonance, producing maximum power. This is done by changing the position of the Primary Tap at different points in the Primary Coil.

But that will only work if your tank
capacitor(s) is around the right size. You
must use JavaTC! (To gain entrance to the
ballpark)

Also, why use two coils in series for the primary, instead of just one bigger one? It looks like he center taped it but I don't even know what center tap means, and how I'd do that for mine and wire it to the ballast.

That is only if you want to use a ZVS driver, or another flyback driver that uses what we sometimes like to call a push-pull. If you still want to continue using the ballast, all you have to do is recreate whatever primary you were using before.

Everything you ever wanted to know about center tapped coils

 

[USAbro]

The secondary sounds pretty good, then.
The primary should ideally be more like 15
turns if you can.



Just keep going on it then. That will be
great fun if you can get it going, it just
won't run a Tesla coil. For that, you can
use another DC flyback, or an ignition
coil, or something else with a lower
frequency.



Ahh, well that means you have not yet
learned how to properly tune a Tesla coil.
Here is a relevant quote from a great site
I found using Google.



But that will only work if your tank
capacitor(s) is around the right size. You
must use JavaTC! (To gain entrance to the
ballpark)



That is only if you want to use a ZVS driver, or another flyback driver that uses what we sometimes like to call a push-pull. If you still want to continue using the ballast, all you have to do is recreate whatever primary you were using before.

Everything you ever wanted to know about center tapped coils

Wow, thanks. +rep if I could. Later.

Anyways, can an ignition coil be driven with a lamp ballast?:drool:

Around on Yahoo answers, people say lamp ballasts drive at about 15khz-50khz and output about 1.5kv not under load. Around 30 volts under flyback load.

Why can't an AC flyback run a Tesla coil? Can I make it DC by using a high voltage diode?

 

[Sigurthr]

I don't understand what you mean by "tap".

Also, why use two coils in series for the primary, instead of just one bigger one? It looks like he center taped it but I don't even know what center tap means, and how I'd do that for mine and wire it to the ballast.

Before it burned out, when I powered on the flyback with the leyden jars in parallel with one flyback lead and then connect to the other, it seemed fine. It made a white blue sparking and a loud buzzing, and the closer the spark gap the higher pitch the noise was and vice versa.

A "tap" is a connection point. A center tap is a wire going to the center turn of a coil.

THERE ARE TWO CIRCUITS FOR THE ROYER "Mazilli" ZVS;
1) Uses a center tapped primary, where each "leg" (from outer turn to tap) is alternately pulled to ground through a FET/IGBT and power is applied through the center tap.
2) Uses a parallel LC circuit with no center tap, where each side is alternately pulled to ground through a FET/IGBT and power is applied at the outer turns through an inductor which prevents shorting the power supply to ground when the switches turn on.

THE SPARK INITIATION DISTANCE SHOWS THE VOLTAGE, NOT HOW FAR YOU CAN "STRETCH" AN ARC; THAT SHOWS CURRENT.

I said this earlier as well: There are AC components of a DC flyback!
1) The first component is the Voltage Ripple across the EHT output.
2) The section of secondary winding between the "lowest" internal diode's Cathode and the HV-Return output acts like an AC output in series with the rest of the secondary winding. You will get unrectified AC out of the HV-Return which has a voltage that is relatively high relative to Earth. This voltage will capacitively couple to the environment.

TLS is right about not being able to use an AC flyback or even a DC flyback without special components, to power a Spark Gap Tesla Coil. The AC signal output just gets shorted out by the storage/filtering (parallel, before spark gap) capacitor.

You can however use an AC voltage source for a CW Tesla Coil, but it requires a lot of work as you have to tune the secondary resonator and optionally the primary tank circuit to the drive frequency of the AC voltage source. I.e. an AC flyback transformer like Fiddy's driven at say 100KHz, connected to a primary tank LC circuit that is resonant at *120KHz (or higher), and a secondary resonator that is resonant at 100KHz. *As long as the primary's resonance is above the drive frequency it will appear as an inductive load and limit resonant rise voltage runaway. Leaving out the tank capacitor essentially causes the primary resonance point to skyrocket. In this scenario the inductive impedance of the primary coil sets the maximum current draw of the circuit. This is standard SSTC theory.

Re: USAbro - your flyback was using a lamp ballast for a driver, which is a fixed frequency HF AC current source. Others here were using ZVS drivers. The two are not interchangeable in terms of set up or operation. The AC signal components coming from your DC flyback secondary before it burnt out were being shorted by the parallel leyden capacitances and the losses in those capacitors. It probably had a lot to do with why the secondary burnt out as there was likely VHF ringing from the parasitic oscillations which was too fast and too high voltage for the internal diodes. If you want to use your rewound flyback secondary for a Tesla Coil you either need to do as above for a NON-spark gap coil, or add in a RF rectifier string to replace the diodes that were in the old secondary so you can use it with a spark gap.

 

[USAbro]

Ahhhhhhh I don't understand all the terminology.

It worked before with the flyback and the tesla coil, why can't it work if I rewind it now?

Maybe I should give up, anyone want to buy my secondary for $15?

 

[Sigurthr]

Theory 101: Capacitors block DC current, but pass (like a resistor) AC current.

In your spark gap tesla coil you had leyden jar capacitors across the output of your flyback, which output both AC and DC. The AC part got shorted, and thus it burnt out your flyback. Your new one will *only* put out AC, which again will be shorted by those capacitors. You can use special RF high voltage diodes to convert the AC to DC, so it won't get shorted out, and then it will work for a spark gap tesla coil.

Giving up is exactly why you don't understand some of these terms and concepts. Buckle down, and steele yourself if getting this project is important to you, if it isn't then move on.

Oh, and for the record your flyback powered tesla coil didn't work before, it just yielded some output. The two situations are miles apart. You're on the road, just not at the destination.

 

[upaa27]

Does anyone else want to see
upaa27's coil? It must be really cool.

USAbro,

I know someone who made a coil about 2 years ago with a tank cap consisting of salt water and many soda Bottles and powered by a 4 kv 60hz nst. They estimated 1 million volts but the arc length said 700kv. A little over 2 feet arcs! Not too bad for a crude sgtc eh?

As I said, he didn't use a flyback it was an nst. It also wasn't my coil but a friend's.