Hivolt stack pumpin' out the juice

[Jon Rosenstiel]

I’ve got my recently acquired 100 kV, 100 mA, 8-stage, air-insulated, Farnell-Hivolt multiplier stack in full service powering my fusor.

First pic shows the overall setup.

Second pic shows the complete power supply. From the bottom up:
Cabinet containing IGBT full-bridge series-loaded-resonant driver.
8-stage multiplier.
Ballast resistor. (340 Kohm water resistor).
Toroid left over from my Tesla coilin’ days.
Metering voltage divider. Consists of ten, series connected 100 Mohm tiger stripe resistors under dielectric oil. Not visible is a small bracket anchoring the divider to the overhead joist.

Third pic shows a recent runs operating parameters. 80+ kV at just over 7 mA with a chamber pressure of 8.9 mTorr. Ludlum BF3 detector was indicating 92 mrem, which works out to 3.3E+06 neutrons / second.
Another run at 75 kV, 12 mA netted 4.3E+06 n/s. (120 mrem)

While testing the over-voltage shutdown circuit I ran the voltage up to just over 100 kV. (Fusor was at base pressure, so it was drawing no current). No problems were encountered, and there was very little corona.

At these high voltages and low currents my fusor’s operation is somewhat unstable, the “fire” likes to go out. Guess I’ll have to drag out the magnetron ion “keep-alive” source.

Jon Rosenstiel

[Steven Sesselmann]

Jon, That is very impressive. What is the white pole with black cable that goes up into your ceiling?

I like your lab too... I would love to have all those things on hand, instead of having to scrounge around every time I need a component.

Steven

[Jon Rosenstiel]

Hi Steven,

The white pole is 1 inch PVC pipe and contains my voltmeter divider resistor string.

Yeah, it's nice to have things on hand when you need them. I guess that's one advantage to gettin' old... you gather lots of stuff. (Another advantage is you get to retire and play ALL of the time)!

Jon Rosenstiel

[DaveC]

Very pretty Jon !


Glad it is all working. With all the power, you should be able to ignore the HVPS part of the equation and concentrate on what the fusor is doing. Nice, clean layout, too.

Dave Cooper

[Starfire]

At 10kw you should also be able to heat the home in winter - can we expect some exciting expeiments now?

I for one will watch this space.

Tesla - eat your heart out - Rosensteil is on the scene.

long may she run.

[Jon Rosenstiel]

John,

While the stack is rated for 10 kW, the stack's driver is limited to somewhere around 2 kW.... so it's only a space heater, not a whole house heater.

JonR

[Richard Hull]

Very nice, Jon. You and Carl will be trading numbers for a while. He wants the lead, badly and he will probably take it at some point for a while until you surge over it again.

This is outta my league. I just hope to hit the mega mark one day.

Richard