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EvilTesla-RG

Thu Jan 08 2009, 04:27PM

Registered Member #1523 Joined: Sat Jun 07 2008, 02:05PM
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Posts: 97

I am trying to build a Rail-Gun attachement for my Tesla Coil.

However, Rail-Guns require DC, or Chopped DC.

So, I need a Simple diode that works with primary circuits on SGTC's.

I was thinking, since sparks jump easier off of points than flat or rounded surfaces, why can't I create a spark gap that has one flat or rounded plate, and one plate with a nail.

Would this work as a HV diode?

Arcstarter

Thu Jan 08 2009, 05:36PM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

No, it would not. You can just get a bunch of 1n4007 diodes, they are 1kv and 1 amp, depending on your nst you can just series maybe 30 or so. For a 15kv nst use something like 50(this maybe a little too much, but i just rounded to the nearest number i like :P).

A rail gun requires large energy storage. How are you going to find a cheap enough high voltage capacitor to use? If you cannot afford a diode, you cannot afford a big enough capacitor for a rail gun. Small to medium tesla coils use a few joules in their cap bank. For a rail gun, you would need hundreds of times more than the tank cap.

EvilTesla-RG

Thu Jan 08 2009, 08:10PM

Registered Member #1523 Joined: Sat Jun 07 2008, 02:05PM
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Posts: 97

Rail Guns don't necisarily require capacitors. I read a site were a guy uses something called a "Compulsulator" to power it. Which is simply a big Alternator.

Anouther guy made a rail gun work off of a nine volt battery. Albeat it was very slow, it was nonethelless a rail gun.

I belive my Tesla Coil has a few more amps than a nine volt battery.

Also, going back to college in a few days, so I might just drop this. However, I may look into the Diodes.

Arcstarter

Thu Jan 08 2009, 08:14PM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

In fact, 9v batteries have more current than a neon transformer. yours is probably like 30-60ma and a 9v can probably short at half an amp or something.

Myke

Thu Jan 08 2009, 11:49PM

Registered Member #540 Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969

Rail guns usually use a bank of capacitors because they can supply a high current pulse for a short time. It is a lot easier to use a low current power supply to charge up the bank then dump that energy than to use a high current supply.

1N4007s are not all that fast so I don't think they would work well for flybacks or TCs. I wouldn't recommended trying to rectify a TC because of the huge corona losses that you would have.

Arcstarter

Thu Jan 08 2009, 11:56PM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Myke wrote ...

Rail guns usually use a bank of capacitors because they can supply a high current pulse for a short time. It is a lot easier to use a low current power supply to charge up the bank then dump that energy than to use a high current supply.

1N4007s are not all that fast so I don't think they would work well for flybacks or TCs. I wouldn't recommended trying to rectify a TC because of the huge corona losses that you would have.

Well, he is talking about the primary circuit. Whether he means NST, i dont know.

If you are trying to rectify the NST, 1n4007's will work, but a NST by itself will absolutely NOT shoot anything. It requires very high currents for a proper rail gun, and that would require a large pulse capacitor. And to use it at NST voltage, it would be a very expensive capacitor. Also, a proper rail gun uses a very short but high current pulse.

EvilTesla-RG

Fri Jan 09 2009, 12:32AM

Registered Member #1523 Joined: Sat Jun 07 2008, 02:05PM
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Posts: 97

Yea, I was talking about the Primary.

I understand that about the secondary, but the Primary, being a sieries LC circuit and all, has some pretty good amperage.

So the Diodes would NOT work with the primary.

That settles it, I will not be turning my Tesla Coil into a RailGun in the Near future. In the Far future however, I hope to build and design railguns like which this world has never seen. Though, often my ambition out-does my skill.

HV Enthusiast

Fri Jan 09 2009, 01:30AM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
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Posts: 3068

1N400X type diodes wouldn't work with a tesla coil primary anyways as the frequency is in the 100's of kHz.

rp181

Fri Jan 09 2009, 01:56AM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
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Posts: 1529

compulsator's are extremely complicated. They have only been done by (in the USA) by NASA and several universities. They require a custom alternator with low inductance windings, and a extremly fast motor to wind it up. The flywheel as to be strong, as centripital force will rip it apart.

EvilTesla-RG

Fri Jan 09 2009, 04:55AM

Registered Member #1523 Joined: Sat Jun 07 2008, 02:05PM
Location:
Posts: 97

strange, becouse this guy builds them as a hobby

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