Introduction and Purpose

[Jonathan Filip]

Hello!

My name is Jonathan and I dabble a bit in high voltage and plasma phenomena both in atmosphere and under vacuum. I am currently developing a product for my company and said product is designed to resemble a star via plasma phenomena in vacuum (I will not state my company’s name nor the product name at this time due to potential repercussions on this forum). This started when I discovered a video on YouTube where a guy made a plasma device which resembled a star. This person touts the name “primer fields theory” or something along those lines. I have not looked into his theory much but his device and patent are extremely interesting and I was able to recreate the effects he demonstrated using a similar approach. Essential I am a washed civil engineer who is in love with aether and electricity. I am feverishly pursuing the before mentioned product I am making but my experimentation is very diverse. The HFSSTC circuit used to power the plasma toroid or donut is something I have recently been pursuing. I am very close to getting it to work but I must find a suitable inductor for the globe first. If anyone has or is getting rid of a transformer that is >40kV then I will happily take it off your hands (if you have an x-ray transformer I’d also love to have it or if you know where I can get one that information would be great too). One of my greatest ideas to date is a vortex Hg engine which is designed for vertical propulsion (essentially a very complex electric motor or faraday disk motor). I have yet to make a final design but I do own 100g of Hg! One question: if I make a 100kV Cockcroft Walton generator do I really need to be worried about the x-rays if I run it under vacuum?

[Rich Feldman]

>> One question: if I make a 100kV Cockcroft Walton generator do I really need to be worried about the x-rays if I run it under vacuum?

Welcome. You might be the first to run a CW multiplier under vacuum.
If you mean connect the multiplied voltage (100 kV) to an electrode under vacuum,
[edit] as practiced by Cockroft and Walton, [\edit]
then it's x-ray safe as long as no current flows.

[Jonathan Filip]

Really? I thought that was one of the main power supplies for fusors (the CW or a HVDC power supply). I really like using AC currents in fusors but for the experiment I'm running I need a higher voltage to get the phenomena I'm looking for.

An x-ray transformer or something similar would make things a lot easier but for now I will have to depend on the multiplier.

[Rich Gorski]

Johathan, Welcome to the forum.

Your question about whether operating a CW generator in vacuum will produce X-rays really depends on the pressure the thing is immersed in. If your generator is creating anything above say 10-15kV and if your pressure is above 0.1mTorr to maybe 100 Torr you will be creating plasma in the chamber. There will be X-rays produced from accelerated electrons in the gas. Running a CW generator in vacuum will require a pressure well into the 10-5 Torr range if you don't want plasma created in that environment running along the diodes and capacitors. That probably means having the chamber continuously pumped with a turbo or diff pump. You might be better off immersing the thing in mineral oil or at least run it at atmospheric pressure with proper corona discharge management. When I was at the university we built a CW generator capable of 125kV that was immersed in mineral oil and running at 30kHz. When we turned it on at such high voltage the fluorescent lights in the room also started to flicker.

I'm vaguely familiar with the concept of primer fields and I have seen those videos. I don't know if any of that is real or not but certainly interesting.

Rich G.

[Jonathan Filip]

Dang that’s awesome. I always put my CWs in oil. Sometimes I put mine in mineral oil but I’ve been settling for vegetable oil these days due to price. Hopefully my CW can output close to the one you made at university.

Initially I plan on running my CW with a 15kV 60mA 60Hz NST. Do you think this is sufficient??

I can also power it with a fly back but I need an AC fly back and it looks like I’ll have to make one since all the fly backs now are DC.

[Rich Gorski]

Building a CW multiplier from a 60 Hz NST is certainly doable but because of the low frequency you will need larger capacitance capacitors to make it effective. Since the older NSTs are center tapped (grounded) it would be best to make it a full wave CW (sometimes called a 3 stage) multiplier. See the diagram below.

fullwave CW multiplier.jpg (12.41 KiB) Viewed 1060 times

You can also find old TV flyback transformers (designed for 15kHz) on eBay but you will have to build a 15kHz driver for it. I've also seen flyback power supplies on eBay complete with driver. Some of these have multiple flyback transformers connected in parallel to boost current.

Good luck with your build.
Rich G.

[Rich Feldman]

Good luck, Jonathan.
There are many good resources at the voltagemultipliers.com website under support/design.
Rich G's schematic of a full wave multiplier looks like it might have come from that site.
Not only HV parts catalog and design formulas, but app notes for things like diode power dissipation in oil, and guides for screening of components and assemblies in production.

[Jonathan Filip]

I forgot about how the nst is wound. But even still wouldn’t one end of the secondary be at -15kV and the other end of the secondary be at +15kV? So wouldn’t a normal CW have the same output as the 3 stage CW if the number of stages are the same?

Also in the diagram you presented is that a total of 3 stages but basically two sets of 3 stages?

I may wire it the way you presented but I’m shootin for a higher voltage so I may go standard. Mainly cause I got some flybacks to boot. I got a ZVS driver for it but it’s probably gonna blowup quick bc the last one went in about 5 minutes.

Thanks for all the help yall and I’ll definitely check out that website for the CW. I’m running some experiments tonight and I have a 3 stage CW that I’m powering with the flyback so hopefully that’ll do something in the vacuum chamber.

[Richard Hull]

On all NST from 7.5kv to 15kv nameplate. The rated potential appears across the two end insulators. The metal case is grounded and is the center tap of the HV winding. On a 15kv NST the grounded case to each insulator is 7.5kv. It is important to always ground the case to prevent the case going hot if someone foolishly grounds one insulator in an attempt to get the full 15kv above ground. This will float the case at 7.5 kv and can kill whoever touches the metal case.

Thus the most you can get safely out of a 15kv transformer in a simple rectification 2 diode full wave filtered DC under zero load is 1.414 X 7500 = 10.6 kv to a safe grounded case.

Again this is all in the FAQs already asked and answered years ago here. But hell, nobody ever reads them. Why bother? I'll just ask the same stupid question over and over again.

You will forever be doomed to be ignorant of all related to fusion and fusor construction until, oddly, you learn to read the FAQs.

We created the FAQs in each forum thinking that most arriving here could:
1. Read
2. Act in a manner towards self-directed study via reading.
3. Help us older folks to not have to constantly Spoon Feed every newbie who lands here.

Oh how wrong we were to figure on a higher caliber person landing here every time.

Read the FAQs!!!!

Richard Hull

[Jonathan Filip]

Ill check out the FAQ. Thanks

[Howard Evans]

This post if from newbie Howard Evans. My next task is the read the FAQs, as Mr. Hull (apparently) frequently requests newbies such as myself to do. But I am commenting on this CW topic under "Introduction and Purpose" because I do have some hands-on experience in this area.

The Cockroft-Walton generator is the diode form of the Marx high voltage generator. You basically charge capacitors in parallel and discharge them in series to produce high voltage. In our laboratory we had a tandem linear particle accelerator that could be operated with up to 1.7 million volts of terminal potential. It uses a pair of power-tetrode electron tubes to create a push-pull power oscillator that drives a center-tapped transformer-connected Cockroft-Walton voltage multiplier. This configuration is similar to the one shown in a diagram posted for a dual CW charging system. The entire CW, as well as the accelerator "tank" housing the gas stripper canal, its high-voltage terminal, and two acceleration columns, is filled with sulfur hexafluoride insulating gas at 120 psig pressure. The tank interior walls are lined with lead plates, because x-rays will definitely be generated as a byproduct of particle acceleration.

Even so, there would be intermittent tank-arcs when operating at high acceleration potentials. I believe these occur when a cosmic ray ionizes and provides a conduction path through the SF6 insulating gas. I saw a similar demonstration in the 1950s with my grandparents while visiting the Atomic Energy Museum located in Oak Ridge, TN. It was just a large, transparent, rectangular tank with metal plates on the top and bottom that were charged to a high voltage. Ordinary air filled the tank. If you waited long enough, sooner or later a cosmic ray would cross the chamber from top to bottom, creating an ionization track discharging the charge placed between the top and bottom plates. The noise of the crack this "lightning" -like discharge made could be heard throughout the museum. Same-o, same-o when the Tandetron "burped". There is no solution to this problem that I am aware of. Cosmic rays penetrate everywhere, even into the deepest mines. There is no practical shielding that I know of that is guaranteed to stop a cosmic ray.

We also had several other lower-voltage kilovolt power supplies that used a fly-back transformer and a CW string to produce as much as 30 kV in air with only air and fiberglass insulation. One of these was used during our PCSS development to charge a coaxial cable delay line that was then discharged into a load by optically triggering the PCSS. I had to design and build a PCSS device holder that covered the PCSS with mineral oil or Fluoroinert liquid to prevent flash-over across the PCSS surface while the delay line was being charged.

In general, electrons emitted and accelerated in a vacuum environment can and will generate x-rays if enough potential is used. People became concerned when color televisions were shown to emit x-rays because of electron impacts on the shadow mask, but it only takes a few feet of distance from the set before the x-rays are attenuated to safe levels of exposure. I had a scintillation detector that I used to "sniff" for x-ray radiation leakage around the working areas of my accelerator. This mostly occurred near glass view-ports, so I would avoid being near those when accelerating ions. Just use caution when working with both high-vacuum and high-voltage simultaneously. A reusable optical dosimeter can be charged up and worn each time you fire up your Fusor, but these do not respond to neutron flux. In my opinion, for that you should be behind lead shielding AND have a sensitive neutron detector if you expect neutron production. Really, you have to be an advanced Fusor builder to worry about that. And, yes, you advanced Fusor builders do need to worry about neutrons. Play safe, always!