HV feedthrough & chamber insulation

For posts specifically relating to fusor design, construction, and operation.
Post Reply
Taylor Shead
Posts: 9
Joined: Sat Oct 20, 2018 8:09 am
Real name: Taylor Shead

HV feedthrough & chamber insulation

Post by Taylor Shead » Sat Dec 08, 2018 7:46 am

So I modeled our fusor in SolidWorks after getting the correct measurements from a bunch of eBay parts (also the reason the vacuum attachment is wonky). It is not done but it is coming along nicely.


Our setup thus far:
Image


My question:

After proper vacuum get pulled on it, won't the HV line all the way to the grid need insulation? What are people using that's demo fusor rated?
Our feed through is rated to 20kV (iirc) but can I just surround the line the the grid with PVC and hot glue it to the feed through? Will I need something more complicated?

Envisioned without insulator (EMF goes to chamber wall after exiting feed through):
Image

Envisioned with insulator (EMF goes to chamber wall after reaching grid):
Image

User avatar
Richard Hull
Site Admin
Posts: 10992
Joined: Fri Jun 15, 2001 1:44 pm
Real name: Richard Hull

Re: HV feedthrough & chamber insulation

Post by Richard Hull » Sat Dec 08, 2018 4:19 pm

Most people use alumina ceramic tubing on the grid stalk. No plastic or hot glue allowed.

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
Posts: 9
Joined: Sat Oct 20, 2018 8:09 am
Real name: Taylor Shead

Re: HV feedthrough & chamber insulation

Post by Taylor Shead » Sun Dec 09, 2018 9:22 am

So how do I surround the already ceramic feedthrough with more of the stuff? I’ll post an image of our feedthrough when I can to help but on the end are nuts threaded on to metal. I think it’s pretty standard.

I just don’t know how to interface with the longer insulator and what to search for to purchase. Or can I make one?

User avatar
Dennis P Brown
Posts: 1566
Joined: Sun May 20, 2012 2:46 pm
Real name: Dennis P Brown
Location: Glen Arm, MD

Re: HV feedthrough & chamber insulation

Post by Dennis P Brown » Sun Dec 09, 2018 2:11 pm

You could run an other ceramic tube down the HV lead and use a good ceramic compound/glue to locked it in place. I do that but room is always an issue. If that isn't possible your choices are limited: get a new feed-thru, machine the existing one to handle a thicker ceramic cover - if possible, or (like I do), make your own.

Post Reply