Neon sign transformers for Tesla coil

[billybob]

1800 seems a bit high. How did you come to that number?

500W is probably good for a coil with a 4x25 secondary.

Oh wait no I was wrong... I multiply the secondary transformers voltage by its current right?

 

[billybob]

I got 540 for the new measurement

 

[DerStrom8]

Oh wait no I was wrong... I multiply the secondary transformers voltage by its current right?

That is correct, power = volts * amps, or P = I * V.

 

[billybob]

What should I position the spark gap distance to?

 

[DerStrom8]

That'll require some trial and error. Once you get your transformer you'll want to adjust it as wide as possible while allowing it to still fire regularly.

As a side note, you seem to be using brass fittings. Be aware that the firing of the spark gap will melt and eat away these electrodes very quickly. You will probably need to replace them frequently.

 

[billybob]

That'll require some trial and error. Once you get your transformer you'll want to adjust it as wide as possible while allowing it to still fire regularly.

As a side note, you seem to be using brass fittings. Be aware that the firing of the spark gap will melt and eat away these electrodes very quickly. You will probably need to replace them frequently.

Think stinks, I think I can separate them 1/2 inch max hope that’s enough. Also what metal would you recommend besides tungsten for the electrodes?

 

[DerStrom8]

A very general rule of thumb is 1.1kV/mm of spark. If you have a 1cm gap, you would need about 11kV. Now this is extremely rough and will depend on humidity, height above sea level, air cleanliness, etc., but what I'm getting at is that I think 1/2 inch will probably be fine for what you're doing.

Anything with a high melting point is good for spark gaps. That is why tungsten is usually selected - it has a very high melting point so it stands up in high-temperature applications like spark gaps very well. However, I realize tungsten can be very expensive, so you'd probably be good even with basic stainless steel. Watch out for galvanized steel though, that will emit some nasty fumes.

 

[billybob]

does phasing transformers increase output voltage or current? I experimented with capacitor value on deepfriedneon and when i input higher voltage with lower current the capacitance dramatically decreases, but when I put in lower voltage with phased current I get higher capacitance.

 

[DerStrom8]

Putting identical transformers in parallel with the same phase doubles the current sourcing capability.

On the deepfriedneon page, the frequency, voltage, and current of the transformer is fixed, and should not be changed. It should be set to match the transformer(s) you have. The calculator will then give you the optimal capacitance value. You then use that capacitance to determine the required primary coil inductance in order to match the resonant frequency of your secondary circuit using the formula, f=1/(2*pi*sqrt(L*C)).

 

[billybob]

Putting identical transformers in parallel with the same phase doubles the current sourcing capability.

On the deepfriedneon page, the frequency, voltage, and current of the transformer is fixed, and should not be changed. It should be set to match the transformer(s) you have. The calculator will then give you the optimal capacitance value. You then use that capacitance to determine the required primary coil inductance in order to match the resonant frequency of your secondary circuit using the formula, f=1/(2*pi*sqrt(L*C)).

Ok, I was just experimenting, just gonna be one transformer. I plugged the information in for 9k at 60mA and got 0.0176 uf so Ive been experimenting with the MMC page to see how many I need.