Opinions on WiederLabs 100kV Feedthrough

This forum is for specialized infomation important to the construction and safe operation of the high voltage electrical supplies and related circuitry needed for fusor operation.
Conner Ruhl
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Re: Opinions on WiederLabs 100kV Feedthrough

Post by Conner Ruhl » Tue Aug 21, 2012 4:37 pm

It's pretty awesome that you respond on here, I enjoy reading some of your older posts. Anyways, how do you justify the price tag? It's not unreasonable, but I have found comparable products for much less.

swiederhold
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Re: Opinions on WiederLabs 100kV Feedthrough

Post by swiederhold » Tue Aug 21, 2012 5:05 pm

If we sold them for as much as the first few have cost to make, the price would be significantly higher.

These guys are difficult to make. There was a lot more than just figuring out the ceramics. We had to perfect a metal spinning process to form the expansion joint made from Kovar, as well as the method of welding it to the flange (rather tricky). And, as was mentioned by an earlier poster, ceramic to metal sealing is an art in itself.

As for setting the current price: We figure in the material and labor costs, overhead and profit, and recovery of the R&D/equipment/tooling expenses. Certainly, the price reflects the market as well.
We do see the prices coming down in the future as we refine the process and are able to source materials at a better price.

Scott Wiederhold
WiederLabs

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Chris Bradley
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Re: Opinions on WiederLabs 100kV Feedthrough

Post by Chris Bradley » Tue Aug 21, 2012 5:31 pm

Seems like a good price to me, on the face of it, but, Conner, how much shielding are you expecting to need for the x-rays from a 100kV fusor?

You may really want to consider a staged approach to this. There are multiple problems (as well as shielding) to overcome getting that sort of voltage into a chamber safely and effectively, and getting it doing some useful in there.

Operating at lower voltages first will give you the experience to judge how to approach such a design. Getting the right feed-through is just one piece of the jigsaw. Managing that much voltage is non-trivial in a way that makes handling 30kV look as complicated as swapping out a torch battery.

I don't think you'd be saving any time or money at all by buying 'the ultimate kit' in the first hit. Quite the contrary - lowering your targets in the first instance and follow a learning curve, then you will be better prepared to understand and optimise your future build to achieve your goal.

Conner Ruhl
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Re: Opinions on WiederLabs 100kV Feedthrough

Post by Conner Ruhl » Tue Aug 21, 2012 5:46 pm

Thanks for the explanation!

Conner Ruhl
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Re: Opinions on WiederLabs 100kV Feedthrough

Post by Conner Ruhl » Tue Aug 21, 2012 5:53 pm

I have access to professional assistance from university professors that are helping to make this process easier. As far as shielding goes it will only be operated at full power for very few expirements, and I am aiming for a complete lead surrounding with the device in the corner of a concrete foundation.

The main point of going "all-out" is to have the ability to reach power levels close to 100kV. That level of neutron production is essential for the research aspect of the fusor. Normal operation will only be at voltages of 30kV or less.

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Richard Hull
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Re: Opinions on WiederLabs 100kV Feedthrough

Post by Richard Hull » Tue Aug 21, 2012 6:56 pm

The mega neutron mark in most fusors that have been reported here are all above 40kv but usually under 50kv applied. It is about at 45 kv that x-radiation becomes a concern in the immediate vicicinty of the fusor though you'll measure a decent amount coming through the shell at about 35kv if real close to the body of the fusor.

Good luck with your well funded and mentored project.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Chris Bradley
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Re: Opinions on WiederLabs 100kV Feedthrough

Post by Chris Bradley » Tue Aug 21, 2012 8:07 pm

Conner Ruhl wrote:
> That level of neutron production is essential for the research aspect of the fusor. Normal operation will only be at voltages of 30kV or less.

Conner, I'm not getting a strong impression of an 'enthusiastic' response to the advice the guys above have given. You seem to have fixed in your mind that 100kV is the voltage you need for the neutron rate you want, but why? You're asking people in a forum who have no experience in this regime of voltage.

100kV is a voltage, not a 'power'. What sort of power source do you have, what is its maximum current output at 100kV?

Don't mis-read me, I'm not hoping to dissuade you. Quite the opposite, I'm hoping to keep your expectations real so that you get a solid result. I think that's the best sort of advice in this scenario. But you appear to be asking for advice (in a forum where you should know people don't have experience of running 100kV) yet you then seem to be arguing with the advice too?

If your local professional assistance is confident they know how to deal with 100kV power, then you really need to rely on *their* advice than rely on an internet forum of remote responders without experience in this voltage range.

If you are certain you are going to, and need to, run to 100kV, you have the money to buy a 100kV feed-through (which seems to be a good price to me) and you have professional assistance, then there would seem little that armchair internet advisors at-a-distance can usefully add to your decisions regarding operating at 100kV.

Good luck with your project! A $10k funding pot, professional advice on tap, a 100kV power supply and space to build your project as well, this is an absolute dream ticket for most folks here so make the most of it!

Conner Ruhl
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Re: Opinions on WiederLabs 100kV Feedthrough

Post by Conner Ruhl » Tue Aug 21, 2012 9:52 pm

I only keep mentioning 100kV because that's what I have available. It is a lab HV supply that outputs 100kV and has a price tag of less than $500 (amazing find). I am not entirely sure of the current, but it was in the milliamps if I remember correctly. Otherwise, the 100kV is arbitrary. I just need a rather decent neutron count (1*10^6 to 3*10^6). If I am coming of as argumentative, please don't think that's purposeful. Everything that is said here is considered carefully (all of the people here have much more knowledge of this subject than I). I print out responses and keep them in my notebook for reference later (plus things I discover while browsing. Richard Hull has quite a lot of pages in my notebook). The professional I keep referencing has a doctorate in nuclear physics. He specializes in fusion, and will be helping me with the research side of things. As for the hardware, I am working with my grandpa (works with HV daily) to make sure everything is safe.

I will have to agree with you that this is an absolute dream come true! I wouldn't trade this opportunity for anything!

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Chris Bradley
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Re: Opinions on WiederLabs 100kV Feedthrough

Post by Chris Bradley » Tue Aug 21, 2012 10:13 pm

Conner Ruhl wrote:
> It is a lab HV supply that outputs 100kV and has a price tag of less than $500 (amazing find). I am not entirely sure of the current, but it was in the milliamps if I remember correctly.
Amazing indeed, as a commercial purchase. Where did you find such an item - rare indeed, with a negative going output at such a high potential? So you still need to purchase this, or it is available to you already?

If you get mA's out of it, you'll need to be mindful of how to construct and insulate your interconnections to avoid losing a few mA to coronal losses alone, if you operate at 100kV.

Conner Ruhl
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Re: Opinions on WiederLabs 100kV Feedthrough

Post by Conner Ruhl » Tue Aug 21, 2012 10:45 pm

It's one of those "I know a guy" situations that is unreasonably lucky (the odds of it being available we're just rediculous). I really do need to do some more research on coronal losses. How exactly do you negate them?

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