Well, I've finally committed some green. Bought myself a varactor at a surplus outlet in Minneapolis, and I've ordered some surplus HV transformers. I plan to build the transformer cascade described here,
http://home.earthlink.net/~jimlux/hv/xfrmr1.htm
and use it to drive a three stage voltage multiplier. I figure this should get me into the right voltage range with decent power, and some control.
Considering that this setup will be opperating at 60 hz., optimum capacitors for the voltage multiplier would store one heck of a jolt. Any problems with under-sizing them to reduce the capacity of the system to fry my grid? Or is there a better approach?
Finally laid out some bucks
Re: Finally laid out some bucks
You need to state what your target voltage and amperage are.
But I can tell you from road of hard knocks the 60hz requirement
virtually guarantees big caps. I had to group my 470 pf caps into groups of 4 caps to get near the cycle requirements. (1880 pf)
Keep on Fusing!
Larry Leins
Fusor Tech
But I can tell you from road of hard knocks the 60hz requirement
virtually guarantees big caps. I had to group my 470 pf caps into groups of 4 caps to get near the cycle requirements. (1880 pf)
Keep on Fusing!
Larry Leins
Fusor Tech
Re: Finally laid out some bucks
Brett -
As you probably know, capacitor size affects the output voltage ripple. Half wave multipliers have to sustain the voltage for up to a half period of the charging frequency. At 60 Hz that's about 8 msec. So the pk-pk ripple in the output is approximately equal to the current in mA times the half period in mSec divided by the capacitance in microFarads.
Ripple voltage in the Fusor varies the ion energy which will reduce the neutron yield, but will not interfere with the fusor's operation, soooo... you can opt for safety and keep the caps relatively small.
The only caveat to this is that in the multiplier, the output capacitance is reduced in proportion to the number of stages.
The aids in safety, but worsens the ripple.
As to gird heating, this is in direct proportion to the input current you supply to the fusor. This in turn is in proportion to the voltage you supply and the pressure at which you operate. To operate at higher voltages, you need to get the pressure down into the few microns level.
I would recommend setting up your fusor, and doing a some experiments to characterize it. See Carl Willis' I-V curves for instance.
Dave Cooper
As you probably know, capacitor size affects the output voltage ripple. Half wave multipliers have to sustain the voltage for up to a half period of the charging frequency. At 60 Hz that's about 8 msec. So the pk-pk ripple in the output is approximately equal to the current in mA times the half period in mSec divided by the capacitance in microFarads.
Ripple voltage in the Fusor varies the ion energy which will reduce the neutron yield, but will not interfere with the fusor's operation, soooo... you can opt for safety and keep the caps relatively small.
The only caveat to this is that in the multiplier, the output capacitance is reduced in proportion to the number of stages.
The aids in safety, but worsens the ripple.
As to gird heating, this is in direct proportion to the input current you supply to the fusor. This in turn is in proportion to the voltage you supply and the pressure at which you operate. To operate at higher voltages, you need to get the pressure down into the few microns level.
I would recommend setting up your fusor, and doing a some experiments to characterize it. See Carl Willis' I-V curves for instance.
Dave Cooper
Re: Finally laid out some bucks
Thanks. Looking at the prices on high voltage capacitors, I was probably going to end up using small ones anyway. 
Re: Finally laid out some bucks
My hv diodes just showed up, and the capacitors to go with them are in the mail. (Thanks for pointing out that source in eastern Europe, Larry! Can't beat their prices.) The transformers are on their way, too. So I should have all the parts for my high voltage power supply on hand in a week or two. I've still got to come up with a vacum system, but while I'm saving up for that at least I'll be able to run my Jacob's ladder...
Re: Finally laid out some bucks
Thanks Brett:
You have to save money everywhere you can.
One bad thing is that detection and vacuum will suck the money right out of your pocket!
Keep on Fusing!
Larry Leins
Fusor Tech
You have to save money everywhere you can.
One bad thing is that detection and vacuum will suck the money right out of your pocket!
Keep on Fusing!
Larry Leins
Fusor Tech
Re: Finally laid out some bucks
I'm pretty sure I'll end up just building my own vacum system, (I'm handy around the machine shop.) but I expect you're right about the detectors.
Re: Finally laid out some bucks
Yes! Now my (extremely heavy) transformers have shown up. I should be at least making sparks in a couple of weeks.