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: Computer control
Date: Apr 12, 5:27 pm

On Apr 12, 5:27 pm, wrote:

>Probably what you want is a constant current supply (more than a constant voltage supply).

Yep, with a good filter to slow transient response. And as I have so often suggested, be prepaired to find RF and microwave negative resistance instability. Computers and control systems don't like RF that resonate circuit board traces to disruptive voltages.

>Perhaps a switching supply would be the way to do this, with a SMALL smoothing inductor (so the dynamic response would be good). At work, I am looking at switching supplies for TWTA's right now (8-10 kV) and I will see if I can scavenge a decent easy to build design.

Ooh, wouldn't that be nice to heat a plasma with?

>In summary, it seems that the tough part is the power supply. Anybody got good ideas on an inexpensive source for the transformers for a HV switching supply in the kilowatt range (say, 50 kV @ 20 mA).

http://www.alliedsignal.com/metglas/hfc/powerlit.htm if you want the best cores. Otherwise you might look at computer switching supply cores in parallel. But with more money than time, get the Metglass.

>Somehow, I don't think a TV flyback's going to cut it...

15 Watts, then you better oil-cool the ferrite.

>(But maybe a bunch of HEI coils in parallel/series?... they are in the 100-200 watt range)

Yep, thats what I had in mind for initial pulse experiments. But I'm considering repetitive pulses, with microwaves to keep the grid plasmas hot.

>Switchers, as a class, live or die by their magnetic components.

You can find free or demo design software on the net, I can look up references if you want.