Eastside Prep Fusor

Current images of fusor efforts, components, etc. Try to continuously update from your name, a current photo using edit function. Title post with your name once only. Change image and text as needed. See first posting for details.
Post Reply
User avatar
Joe Gayo
Posts: 404
Joined: Sun Jan 06, 2019 9:34 pm
Real name: Joe Gayo
Location: USA

Re: Eastside Prep Fusor

Post by Joe Gayo »

That sounds like a ground/electronic shielding problem and probably isn't related to the x-rays.

If the discharge is unstable, then there will be high pulse current from the capacitors in the multiplier. The energy in the capacitors increases with the square of the voltage so the discharge current will be very high if there is an arc. Large current pulses produce magnetic and electronic interference that thin walled shielding will not effectively attenuate.

Is there any series resistance in the multiplier or between the multiplier and cathode? There should be! Even though the variac helps limit power, once the voltage is raised the multiplier can deliver significant energy.
Gunnar Mein
Posts: 40
Joined: Sat May 29, 2021 12:24 pm
Real name: Gunnar Mein
Location: Kirland, WA

Re: Eastside Prep Fusor

Post by Gunnar Mein »

This is currently running with our 12 MOhm ballast. Yes, X-rays and trouble might very well be coincidental. I really do need to find you a recording what goes down in that scenario, though.
User avatar
Richard Hull
Moderator
Posts: 14992
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: Eastside Prep Fusor

Post by Richard Hull »

Like Joe, I am positive x-rays play zero role in your issues. I run my fusor on a 60 hz supply as well and just run full wave rectification at 40-45kv with zero filtering. I find any effort to filter even straight out of the high voltage transformer at 60hz in the fusor environment creates unwanted issues, as Joe notes. Just too much joule energy stored in any attempt to filter or smooth things out. Naturally, with a multiplier you must have the capacitance to multiply the voltage and therein lay the rub. The folks with HF switching supplies are more immune to this issue. A stable supply in the fusor arena in a must. Few, if any other devices, work in the region of gas plasmas and narrow, workable pressure ranges found in a working fusor. Thus, the power supply is critical.

RFI abounds in the fusor environment as a norm! However, it is manageable with good practices in place. With modern electronic monitoring and data collection systems using RF sensitive, low level signals entering sophisticated computers and microcontrollers, the noise riding on these signals will reset microprocessors or send them off to process nothingness, or lock up at critical data collecting times. In high joule pulses, the noise peaks can often destroy microcontrollers.

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Post Reply

Return to “Images du Jour”