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: Strike Two
Date: Aug 31, 4:37 pm
Poster: Richard Hull

On Aug 31, 4:37 pm, Richard Hull wrote:

So heres what I tried, small chamber with grids connected to an 8kv, 1.5ma power supply, pumped to a very mild vacuum(very mild). distance between the inner and outer grids about 1.5 centimeters, quite small. I had thought I would see some arcing between the grids or some other energy


Your supply was way underrated! You will need 20-30 ma before the grids get warm. Sometimes 60 ma are needed to melt grids at lower voltages. My guess is the supply was current limited in some fashion and dropped all of its voltage across an internal limiter resistior or some such thing, which eventually gave up the ghost.

Most glow discharges get visible at around 20mm or lower vacuum with good ball glows occur below 1mm or 1 torr (1/760th of atmosphere. Your statement about your vacuum is a bit nebulous. It sounds like you have no metering or gauges.

The normal glow in my old demo fusor #1, in the plastic desicator, occurred in the 100 micron or .1 torr region and needed about 3 kilivolts and drew about 20ma.

At 1.5ma, your supply could have internally arced somewhere and you would never detect it.

My guess is that you just didn't have the vacuum and, or, the current needed to see a glow. The current limiting in your supply may have also held the voltage below glow mode as well.

Sorry to hear about the hard times.

Richard Hull