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Marx Generator Kits - FREE Kits for Evaluation!

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LAN_403

Sat Feb 02 2013, 09:39PM

Registered Member #4146 Joined: Tue Oct 18 2011, 02:01AM
Location: Wisconsin, U.S.A
Posts: 56

@Alex I have been busy the last few days but plan to mess with it more this weekend sometime. Thinking of doing what you did and try out the marx portion of the kit off a different supply as I haven't solved the mystery of my multiplier not putting out more than i put into it. Glad to see you guys are getting some sparks though!

Houdini0118

Sun Feb 03 2013, 04:28AM

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

yay got it working though it seems not to be firing consistently. It is working nicely off a flyback supply that i think is dc? i removed a huge hv diode from the hv lead but it still seems to work with this so idk. also the spark gaps are very finicy.

Physics Junkie

Sun Feb 03 2013, 05:52AM

Registered Member #7267 Joined: Tue Oct 16 2012, 12:16AM
Location: Detroit, Michigan
Posts: 407

Nicely done. It does seem like your spark gaps are trying to form a continuous spark. Adjustment of the gaps will probably solve that

Alex M

Mon Feb 11 2013, 12:57PM

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

Done some modifications to the HV inverter board and the performance of the marx generator is starting to really show its self.

One thing I have defiantly noticed is that with a higher charging voltage the spark gaps are not nearly as sensitive to spacing as they were.

In fact I seem to be experiencing surface tracking too, guess I need to clean the board surface and only pick it up near the ends to avoid finger grease from contaminating it.

Update: Sorry but before I could film it in action a few parts on my modified charger went pop (two diodes and a capacitor). The marx board its self is fine and after replacing the blown parts on the charger that is also working fine, I think I was just asking too much from it.

Those diodes went out with a hell of a bang!

Shrad

Tue Feb 12 2013, 11:17AM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780

received mine last week, sorry not having mentioned it

neat packaging, nice quality

I'll post a review as soon as I have the opportunity to try them out, I'm currently into some house modifications so this will come later

thanks again for this opportunity!

Alex M

Wed Feb 13 2013, 03:42PM

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

Finally got a video of it running with a decent HV supply. Not certain but I think its around 4.4-5kV in, and around 50kV out.

The camera's rolling shutter makes it look like its miss-firing.

Here with a higher charging voltage the 4.7Mohm charging resistor is defiantly needed. It seems spot on for the voltage this marx generator is designed to run on.

The bad news is that I have managed to kill 4 of the resistors toward the end of the board, they have gone open circuit. I remember seeing 2 of the capacitors at the end light up as-well but a quick check on the capacitance meter shows that they have self healed fine with only a small amount of capacitance lost (a few tens of pico-farads).

As it so happened the blown resistors isolated the last two capacitors which retained their charge, I know this as I got a bit of a shock when I went to adjust the gaps. I think I did a little uncontrollable dance at the same time, shame I didn't capture that on film

Here's a note for anyone with this kit, do NOT make your capacitor spark gaps much larger than 4mm! This is what caused my capacitors to momentarily break down and pop a few of the resistors. How ever tempting it is!

@easternvoltageresearch What wattage are the 1Mohm resistors? since they have a ceramic type of body, I am not quite sure what their wattage rating is.

Apologies if my spelling or grammar is off but I have had a bit to drink, and will tidy this post up when I'm sober.

HV Enthusiast

Thu Feb 14 2013, 02:49PM

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

Thanks for the video. Thats really great. Appreciate you doing that. I will definately upload to our FB page!

The resistors are 1W (although they may be 2W). They are very high quality power resistors, so they were a lot smaller than what you would expect for power vs. size. I will double check.

Thanks again for the video. Nice work!

-Allison

HV Enthusiast

Sat Mar 09 2013, 05:30PM

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

This may seem like a basic question, but can't get my head around it.

A lot of diagrams showing the input to a CW multiplier with the 2nd input tied to GND. Does that assume if line voltage is being used, that an isolation transformer is also being used? I would figure that connectin the CW multiplier directly with HOT and NEUTRAL from the line and then measuring the output with respect to EARTH GND and/or discharging to EARTH GND would be the best approach with an unisolated AC input.

What are your thoughts?
Thank you
-A

Alex M

Sat Mar 09 2013, 07:53PM

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

Not sure if this applies here, but any sort of earth to neutral contact in my house results in the RCD tripping.

Would a small isolation transformer be an option (it would only need to be for low current), or would the cost be too much? As that way you could earth one end of the CW.

Think we need someone with more experience to comment though.

doctor electrons

Sun Mar 10 2013, 02:00PM

Registered Member #2390 Joined: Sat Sept 26 2009, 02:04PM
Location: Milwaukee Wisconsin
Posts: 381

This may or may not help but this is how most homes in the US are wired.
The ground and neutral in residential homes are the same. They are both tied to the same point in the electrical
panel. The reason is redundancy, if a neutral wire should fail the ground will carry the fault back to the panel and not
through anything else hopefully. Now don't get me wrong here, if you were to wire up a gfci improperly it won't work!
The 240 volt system in most homes has a grounded neutral. Meaning that one leg to neutral will give 120 vac, the other leg to
neutral will also give 120 vac. Leg to leg will give 240. You can also get 120 vac from either leg to ground. (go ahead, meter your
outlets!)
I had a friend that was building some audio gear in his basement. He ran out of outlets at his bench and plugged in an extension
cord run half way across the room. He then found out the hard way that the two outlets he was using were on opposite legs of his
mains. Those little circuits didn't like an unannounced 240v hit!

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