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Stepping down 200kv to 1kv

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Andy

Fri Sept 06 2013, 08:08PM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
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Hi Ash Small

Would Nickel work, it is close to Ferrite M33, with properties of 600k and 7.54E-04H/m

Eleccentric

Fri Sept 06 2013, 11:01PM

Registered Member #33460 Joined: Tue Aug 27 2013, 06:23PM
Location: Seattle
Posts: 46

The question to be answered in this thread seems muddled, so I'll focus on the part that I think I can illuminate.

Andy seems to be talking about a very high power influence machine - such as a multi-disc Wimshurst, which would provide the 200kVDC, though the current would be much less than 1 amp. Such a machine (of any reasonable size) might give 200 microamps per pair of discs under normal circumstances, and if built to tight tolerances and operated under high pressure insulating gas can give very high efficiency. The current output is directly related to how fast moving parts of the generator are moving, so making room for theoretical results I'd be willing to consider a figure of 1mA per disc pair. Given a minimum width between disc pair centers of, say, 2cm, this machine would still be 20 meters long not counting the pressure vessel and insulating feedthroughs.

Given that such a thing is possible, would it also be possible to use a sort of reverse-Marx generator? I know the overall efficiency would be destroyed, but as it's an idea I've kicked around a bit previously this seems a good time to suggest it. I've tried my hand at figuring out how the normal Marx topology could be adapted, but with little luck. There are better brains more steeped in ozone and corona on this forum than mine.

Andy

Sat Sept 07 2013, 07:16AM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
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Hi Eleccentric

How did you work out the 1mA?
I was basing my measurements or theory on the capacitance value of one plate discharged through a load times the speed of the next plate in seconds.

Andy

Sat Sept 07 2013, 09:57AM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
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Decided to use a transistor in the setup, this should work

Antonio

Sat Sept 07 2013, 12:41PM

Registered Member #834 Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
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There is an old book entitled "Modern high speed influence machines" that describes techniques to build electrostatic machines, still with classical design, with high current output.

But "high" in this case is really 1 mA for disks with a good fraction of a meter in diameter. For normal hand-cranked machines operating in normal air, 100 uA per section is "high" current. Similar ideas were explored many times, but with few good results. Today there is research being done about the use of electrostatic generators in wind generators and in small generators powered by mechanical vibrations. A DC/DC converter is usually required to reduce the output to low voltage, but it is complicated to make one converting from more than a few kV.

Ash Small

Sat Sept 07 2013, 12:57PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Eleccentric wrote ...

Given that such a thing is possible, would it also be possible to use a sort of reverse-Marx generator? I know the overall efficiency would be destroyed, but as it's an idea I've kicked around a bit previously this seems a good time to suggest it. I've tried my hand at figuring out how the normal Marx topology could be adapted, but with little luck. There are better brains more steeped in ozone and corona on this forum than mine.

Could you not just use a string of capacitors, and 'tap' each capacitor in the string for a lower voltage?.....say a string of 200 caps, each with 1000V across it.

Antonio

Sat Sept 07 2013, 01:06PM

Registered Member #834 Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
Posts: 644

Ash Small wrote ...

Could you not just use a string of capacitors, and 'tap' each capacitor in the string for a lower voltage?.....say a string of 200 caps, each with 1000V across it.

To take all the energy, you have to reconnect all the capacitors in parallel. The problem is finding a practical way to do it.

Andy

Sat Sept 07 2013, 08:29PM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
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Hi Antonio

Thanks, will download the book.

Ash Small

Sat Sept 07 2013, 11:23PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Antonio wrote ...

To take all the energy, you have to reconnect all the capacitors in parallel. The problem is finding a practical way to do it.

Agreed, but there are plenty of semi-conductor devices that can easily withstand 1kV

Andy

Mon Sept 09 2013, 01:52AM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
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