Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Re: setup
Date: Jul 30, 09:18 am
Poster: Richard Hull

On Jul 30, 09:18 am, Richard Hull wrote:

>So, I'm about to start building my fusor apparatus, and I have a few questions for the experienced experimenters.
>1) What's the best kind of insulation to keep between me and the HV components? Polycarbonate? Acrylic?

External to the fusor, either of these will be fine. These are fine, structurally strong insulators. They can be machined, threaded, glued and bear loads.

If just superb insulation is required with no real structural strength demanded, nothing beats Teflon or the very inexpensive polyethylene or polypropelene.

In vacuo it is another matter! The inside of a fusor is a volume with a huge hail of nuclear bullets (deuterons) and near relativistic electrons. They bombard everything. Plastics are low temperature materials, (teflon is one of the best at resisting heat), but the vapor pressure at temperature of all plastics is way beyond that which will allow good vacuums to be maintained.

Avoid all plastics inside fusors which are to do fusion and make neutrons! Demo models can definitely use the better plastics if kept clear of ion and electron streams.

Inside the chamber use only refractory insulators. these include well glazed porcelin or beryllium and aluminum oxide supports. Both of these items can easily handle surface temperatures of 1000 degrees F. All pro vacuum insulators use glazed porcelin or beryillia. R Hull


So far, the best xformer I've found is a piece of test equipment made for the military by Jennings, for testing vacuum capacitors. It's supposedly rated for 75kV (no real specs), but it has a single output pole. So, I guess I'll have to go half-wave. Does this sound realistic? I'm still searching for a more general purpose xformer.

The transformer you have might be ok as long as it can supply 20 mils or so. If it weighs over 30 lbs it most certainly can.

There is nothing wrong with half wave rectification provided a tolerable filter cap is used. a .05 or .1ufd 50kv unit should be fine. Make sure to variac control the input voltage.

R Hull
>3) How do you guys isolate your rigs from your AC? Ideally, I'd like to use a 1:1 xformer and an EMI/RFI filter, along with a dedicated circuit breaker and emergency cutoff. Do you think that's overkill?


Nothing is overkill in the avoidance of being killed! All of you thoughts are good.

The beauty of the single insulator transformer is that the other side is "case" or ground. Make sure that the electrical ground is connected to the case of the transformer if you use one of this design. My X-ray power supply has this arrangment.

Richard Hull