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: Using Higher voltages
Date: Dec 22, 11:08 pm
Poster: Pierce Nichols

On Dec 22, 11:08 pm, Pierce Nichols wrote:

>1) Average output power can't be more than the input power, so if you limit the input power to the transformer, then you're all set. As the load increases on a stack, the ripple increases, and the average voltage decreases.

The problem I see is that it's peak, not average, voltage that destroys things like feedthroughs and capacitors.

>2) Stored energy is just N*C*V^2/2. C is the stage capacitance (don't forget 2 C's per stage). V is the stage voltage. N is the number of stages.. Typically you make the caps big enough so that energy going to the load (i.e. I*V*Tcycle) in 1 cycle (1/60th second) is some suitably small fraction of the stored energy (say, 5 or 10%). Then, if you have a flashover, you're only dumping 10 cycles worth of energy, which probably won't be a disaster and melt the grid, etc.

Ok, it looks like there is a trade-off btwn low ripple (high stored energy) and safety (low stored energy) and that the balance is a matter of experimental parameters and willingness (not to mention ability) to replace blown gear. Is that somewhat correct?