Tesla Coil Build Thread

[The Lightning Stalker]

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

Because there is more to a DC flyback
transformer than just coils and windings.
The secondary coil is not even just one
coil, but several coils in series with
diodes in between. Some of them even have
a film capacitor inside. And in your
earlier comment:

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.

Did you also catch the part in Sigurthur's
post where he said you need extra
components to run a Tesla coil from a DC
flyback? That is why your flyback burned
out. I have blown flyback transformers
before doing the exact same thing (and
other things, quite a few, actually). I
even thought no one had figured out how to
do it until a few days ago. See, I am
learning things too. When it gets really
difficult and you want to give up, that is
when you start learning things.

 

[USAbro]

Yeah I definitely need to learn more. I guess it's just this.

I built a tesla coil and it made 2 inch arcs. I want bigger arcs. So I scale things up. Things don't work. I'm left to wonder how it worked in the first place.

 

[The Lightning Stalker]

That is something, though. Not many people
can say they have made 2" arcs. Most
people haven't even made an arc 1/4" long.

By pure chance, the first attempt just
happened to be slightly more in tune.

 

[USAbro]

That was my mini one too, only six inches high and 1 inch diameter. Blue plasma like arcs from it.

 

[DashApple]

my smallest secondary 2" x 2.1" : D ( old VTTC photo )

SAM_0560 by TwirlyWhirly555, on Flickr

 

[USAbro]

@ionlaser555-cool arcs. Can you please post more pictures.

I noticed that without the flyback, the ballast is putting out 3700 volts (3.7kv) and I was wondering, is that enough voltage to power a tesla coil? It's operating at 16khz, and is outputting the voltage at 30ma. Arcs are 1cm. Initiation distance is less than 2mm. It can easily melt the wire to liquid form.

 

[upaa27]

@ionlaser555-cool arcs. Can you please post more pictures.

I noticed that without the flyback, the ballast is putting out 3700 volts (3.7kv) and I was wondering, is that enough voltage to power a tesla coil? It's operating at 16khz, and is outputting the voltage at 30ma. Arcs are 1cm. Initiation distance is less than 2mm. It can easily melt the wire to liquid form.

USAbro your problem isn't your power, it the the frequency you are using. Unless you get or make an rf cap, you can put as much power into the coil as you want but all that will happen as already stated is you will loose a ton of power.

Easy answer, talk to your local neon sign guy and see if he might give you a discount for an NST.

 

[USAbro]

Yeah, I'll probably just buy one next year. Is it possible to make your own high voltage transformer?

Edit: I'm only using 16000 hz, why is that too high? What's the highest hertz possible with it still working properly?

I was wondering can I wire two microwave oven transformers in series?

Also I don't understand why high frequency is bad. It works good with the caps, making loud banging when the caps charge and discharge, at high speed. Can you explain please?

And how come I'll loose a ton of power.

p.s. Sorry for all the questions, I guess I just learning!

I cut lawns for money, and I'm thinking of either buying a new rc plane, a kit from oneTesla, or just buy a new laser, this coming spring/summer. I get more than $1k so I will buy something with a couple hundred.

 

[upaa27]

Yeah, I'll probably just buy one next year. Is it possible to make your own high voltage transformer?

Edit: I'm only using 16000 hz, why is that too high? What's the highest hertz possible with it still working properly?

I was wondering can I wire two microwave oven transformers in series?

Also I don't understand why high frequency is bad. It works good with the caps, making loud banging when the caps charge and discharge, at high speed. Can you explain please?

And how come I'll loose a ton of power.

p.s. Sorry for all the questions, I guess I just learning!

I cut lawns for money, and I'm thinking of either buying a new rc plane, a kit from oneTesla, or just buy a new laser, this coming spring/summer. I get more than $1k so I will buy something with a couple hundred.

Idk about winding a transformer as you need an iron core and I wouldn't know how to set that up.

60hz is standard for neon sign transformers. 16000 hz is too high because your capacitors do not react well with that frequency. The dielectric is glass which high frequency passes through, basically shorting it and defeating the purpose of the capacitor.

The loud banging is probably either the corona from the caps shorting or the spark gap. Not the caps discharging.

 

[USAbro]

Idk about winding a transformer as you need an iron core and I wouldn't know how to set that up.

60hz is standard for neon sign transformers. 16000 hz is too high because your capacitors do not react well with that frequency. The dielectric is glass which high frequency passes through, basically shorting it and defeating the purpose of the capacitor.

The loud banging is probably either the corona from the caps shorting or the spark gap. Not the caps discharging.

Yes it is the caps discharging. You can charge them, then disconnect them and they hold the charge for 1 minute and still make a cracking noise.

 

[upaa27]

Yes it is the caps discharging. You can charge them, then disconnect them and they hold the charge for 1 minute and still make a cracking noise.

Caps don't make noise in curcuit when discharging AFAIK. The crack is the quick breakdown of the air when you discharge it manually.

But in your case the popping you hear when it's running is the spark gap which is the same thing as above just the gap is positioned so that it breaks down for you.

If you hear noise directly from the cap it is corona

 

[Sigurthr]

The CAPS should be silent, you should only ever hear sound from the breakout and from the spark gap. If you heard sound from the caps themselves it means that they were not able to withstand the AC component of the signal which led to air breakdown causing periodic self discharge.

Yes you can use that ballast without a flyback, but you need to make a "full wave rectifier" out of RF high voltage diodes. They HAVE to be RF or "fast" diodes. Feed the output from the rectifier to your spark gap tesla coil circuit like normal. You may want to make a "full wave greinacher cascade" aka "voltage multiplier" instead as getting a stable spark gap set up for 3kV is damn difficult.

The highest frequency you can use for AC input of a spark gap tesla coil is about 200Hz. Faster (higher frequency) doesn't charge the tank capacitor before the spark gap discharges again, and frequencies above about 1KHz pass right through the filter capacitor and get shorted out.

 

[USAbro]

Oh,cool yea I hear them crackling when I charge them up. Could plastic sheeting be a good dielectric?

 

[Sigurthr]

Yep plastic sheet works well if it is polypropylene (which is used for overhead transparencies). You want relatively thick stuff for the kind power a TC takes.

 

[USAbro]

What about plastic containers?

 

[Sigurthr]

If Polypropylene, sure.

Sheets are just more efficient/effective for building capacitors out of since you can parallel and series them much better.

Other plastics suffer from dielectric heating (from losses) and breakdown... sometimes catastrophically.