Negative Polarity Power Source?

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Taylor Shead
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Negative Polarity Power Source?

Post by Taylor Shead » Sun Nov 18, 2018 4:17 am

Hello

As a few of you may know, I am teaming up with Ben Barnett do build a demo fusor as a research project for the university we attend (UTA). He is an EE student and I am an ME student.

We have access to a couple of power sources:

#1:
Image

Image

#2:
Image

(I thought I had a picture of the front but apparently not)

I know we need the positive side to be grounded. I read a topic here that concluded that you can't just ground the positive. The supply needs an internal positive ground. Is this correct for a demo fusor?

Also it look like our option #1 can be reversed polarity but doesn't meet the amperage requirements.
Our option #2 almost meets the requirements for a fusion fusor but its polarity can't be reversed.


We talked about modifying #1 but I'm not sure our advisor will let us.


Can we make use of one of these for a demo power supply?


Taylor
Last edited by Taylor Shead on Sun Nov 18, 2018 5:56 am, edited 1 time in total.

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Richard Hull
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Re: Negative Polarity Power Source?

Post by Richard Hull » Sun Nov 18, 2018 5:05 am

Regarding altering option #1. Usually all single polarity supplies like this are internally grounded to the case and power line ground in many places within the circuitry. This reduces required insulation internally.

Selectable polarity power supply units are far more highly insulated and place their grounding selector on a larger printed circuit board with pins, well isolated from each other on this "polarity selector switch board"

The polarity selectable supply might barely make a demo supply provided their is no current limiting. If their is limiting at 2.5 ma, then this will not work at all.

You might be back to a neon transformer homemade supply as a demo power solution.

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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Dennis P Brown
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Re: Negative Polarity Power Source?

Post by Dennis P Brown » Sun Nov 18, 2018 12:22 pm

For a demo fusor any power supply that allows the device to create a visible plasma meets your goal. Even a positive supply is absolutely fine for a demo device. Also, any low current supply is acceptable if it creates a visible plasma (like a NST.)

A demo fusor can be any level - even include deuterium gas for proper color but this device is only created to make an observable plasma.

Obviously, if one ever hopes to do real fusion in a fusor, a proper power supply (polarity, current and voltage) would then be needed and is a better approach for the demo since it will provide real experience handling both the voltage, current and issues of creating a stable plasma (assuming one is operating in the correct vacuum range.)

The power supply you show in the image is perfectly acceptable for a demo system. But that isn't a NST and that supply is dangerous; as such, careful precautions should be taken.

Taylor Shead
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Re: Negative Polarity Power Source?

Post by Taylor Shead » Tue Nov 20, 2018 2:27 am

So if I used a power source with positive supply would I still wire the positive to the chamber and negative to the grid?
This is correct as I understand it but I want to make sure. We will likely stick with the bigger power source as it is cost effective. As for dangerous, we will be working in a room full of stuff that could kill us haha.

Fusion MAY be later (Summer 2019) but we are focused on the demo aspect currently.

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Richard Hull
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Re: Negative Polarity Power Source?

Post by Richard Hull » Tue Nov 20, 2018 7:14 am

Ideally, the purpose of a demo fusor is to create a learning tool that is a look-alike and work-alike for a fusor. Only a negative hot, positive grounded supply will serve here.

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.

Bern Bareis
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Re: Negative Polarity Power Source?

Post by Bern Bareis » Tue Nov 20, 2018 6:51 pm

-30kV, 20mA supply Spellman DXM30N600X4215 for $500: viewtopic.php?f=20&t=12493

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Rich Feldman
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Re: Negative Polarity Power Source?

Post by Rich Feldman » Fri Nov 23, 2018 8:39 pm

Hey Bern, it's good to see you helping out at fusor.net.
Done any work lately with your own fusor?
Richard Feldman

Taylor Shead
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Re: Negative Polarity Power Source?

Post by Taylor Shead » Sat Dec 08, 2018 6:23 am

Richard Hull wrote:
Tue Nov 20, 2018 7:14 am
reate a learning tool that is a look-alike and work-alike for a fusor. Only a negative hot, positive grounded supply will serve here.
So the negative hot is an absolute must? This will be difficult for us because we are on a time schedule. Most people aren't.
Bern Bareis wrote:
Tue Nov 20, 2018 6:51 pm
-30kV, 20mA supply Spellman DXM30N600X4215 for $500: viewtopic.php?f=20&t=12493

I'm pulling my hair out right now because I just saw this and it sold two days ago. I would have picked it up too. Oh well.

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Richard Hull
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Re: Negative Polarity Power Source?

Post by Richard Hull » Sat Dec 08, 2018 4:12 pm

If you really need fusor related stuff, a daily visit to the trading post is recommended.

That fabulous supply has been languishing, un-sold in the trading post since October 27th.

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.

Taylor Shead
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Real name: Taylor Shead

Re: Negative Polarity Power Source?

Post by Taylor Shead » Sun Dec 09, 2018 9:26 am

I couldn’t have purchased it until this week but now that money is gone. Our budget for the demo does not include a power supply. All I need to know right now is if there is ANY way we can use a positive supply.

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