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Marx Generator Kits - FREE Kits for Evaluation!

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LAN_403

the mad scientist

Fri Mar 22 2013, 05:40PM

Registered Member #3768 Joined: Tue Mar 22 2011, 12:46AM
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Posts: 107

I would absolutely love to have one of these kits.

HV Enthusiast

Thu Nov 07 2013, 02:12PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
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Posts: 3068

UPDATE: Finally respinning the marx generator board with a new arrangement for spark gaps using brass nuts. Stay tuned for more details.

HV Enthusiast

Sun Apr 20 2014, 01:25PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
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Posts: 3068

Good morning everyone. I know its been awhile, but was distracted with other projects.

I have new boards coming in. These will include increasing the size and pulse capacity of the charging resistors, as well as implementing polished brass acorn nuts to be used as spark gaps among other things. I"ll let you know when they come in and those who have previously tested the original marx generator board are welcome to evaluate the play with the new kits.

Stay tuned!

Alex M

Sun Apr 20 2014, 04:07PM

Registered Member #3943 Joined: Sun Jun 12 2011, 05:24PM
Location: The Shire, UK
Posts: 552

Awesome! Count me in.

I think increasing the capacity of the charging resistors is a good idea since on the original boards they were very easy to destroy from over voltage if a spark gap is slightly too big.

The capacitors on the other hand seem to be indestructible and self heal after an over voltage event.

HV Enthusiast

Mon Apr 21 2014, 12:36PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
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Posts: 3068

Great! We are also increasing the size of the capacitors ten-fold and increasing the stage count. The total height of the new generator will be about 2-3x longer.

I'll keep you posted!

Alex M

Mon Apr 21 2014, 10:35PM

Registered Member #3943 Joined: Sun Jun 12 2011, 05:24PM
Location: The Shire, UK
Posts: 552

EVR wrote ...

Great! We are also increasing the size of the capacitors ten-fold and increasing the stage count. The total height of the new generator will be about 2-3x longer.

I'll keep you posted!

Just saw on facebook that these versions are 100kV. Nice!

HV Enthusiast

Tue Apr 22 2014, 03:12PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
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Posts: 3068

Theoretically they will be about 100kV. 6kV input with 15 total stages, so in practice the output voltage will probably be around 50-75kV depending on the voltage source and any coronal losses in the system.

But for the intent of the design, that should be plenty voltage as this is intended for educational and desktop use.

The boards have been ordered and should have them by Monday of next week. They are 0.124" FR-4 and measure approx. 2" x 20" in size with vertical mounting provisions. They will also utilize 2W resistors vs. the original wimpy resistors that were used that you guys were blowing and the stage capacitance is also 10x as much.

Alex M

Tue Apr 22 2014, 11:35PM

Registered Member #3943 Joined: Sun Jun 12 2011, 05:24PM
Location: The Shire, UK
Posts: 552

Maybe the original resistors were theoretically adequate in power rating, but just physically too small for these voltages? Looking at my evaluation board I can see small streaks down the side of the failed resistors.

Excuse the dust, it lives on a project display shelf in my bedroom.

I guess that a kit like this needs to be run on the conservative side when it comes to component power ratings, which if intended to be sold as an educational kit should be fine. Definitely not in the 4hv spirit of everything is still working lets give it a tad more juice

EVR wrote ...

the stage capacitance is also 10x as much.

Wow, how big are those capacitors?

HV Enthusiast

Wed Apr 23 2014, 01:22AM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
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Posts: 3068

The resistors are definitely undersized voltage-wise, but that's just the nature of the beast, especially for something where you want to keep costs down.

True high voltage resistors would probably run about $10-15 each for standard 2W resistors, so you just have to use whats available and inexpensive.

The original Marx generator used 1000pF capacitors. The new one will utilize 10,000pF capacitors.

Again, tough finding high voltage caps economically. Sure, for a one-up build for yourself you could easily scrounge some on Ebay for next to nothing, but for a production release board, you need to find something that will always be readily available and inexpensive as well.

Houdini0118

Wed Apr 23 2014, 02:21AM

Registered Member #8558 Joined: Thu Dec 06 2012, 11:38PM
Location: usa
Posts: 57

Did you get the multiplier for running it off the mains working better as well?

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