Linear deuterium Accelerator-Ion Gun Issue

For the design and construction details of ion guns, necessary for more advanced designs and lower vacuums.
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Dennis P Brown
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Re: Linear deuterium Accelerator-Ion Gun Issue

Post by Dennis P Brown » Sun Mar 20, 2016 5:32 pm

John, thank you very much for the advice and especially the paper. I will read it. I am determined to test ideas/approach (as long as I needed put significant money into the idea) and check results. Discovering that a lot of people out there make mistakes and post without proper testing (ugh!) Still, fun to test ideas but I do desire to make progress at some point!

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Dennis P Brown
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Re: Linear deuterium Accelerator-Ion Gun Issue

Post by Dennis P Brown » Mon Mar 21, 2016 11:11 pm

Located an inexpensive source of "rubberized" fabric. That is JoAnn Fabrics ( http://www.joann.com/rubber-sheeting-wh ... l#start=10 ) Hope this works but is very inexpensive so worth a try. Cotton backed and white so I assume it wouldn't be conductive (unlike many "black" rubbers since these often contain carbon - or so I have read.)

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Re: Linear deuterium Accelerator-Ion Gun Issue

Post by John Futter » Tue Mar 22, 2016 1:09 am

Dennis
I have just looked at our accel.
belt charge 5kV 128uA
Corona stabiliser is @ approx 60uA for 1.9MeV
Column current is approx 70uA

which is close to 130uA total load which equates with the 128uA of belt charge PS the belt also produces charge with out the spray

target current after being through slits and collimators = 22pA

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Dennis P Brown
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Re: Linear deuterium Accelerator-Ion Gun Issue

Post by Dennis P Brown » Tue Mar 22, 2016 9:47 am

Thank you John; that really helps me get a handle on issues like no other source has to date. Knowing the current (both applied and achieved) is critical in understanding what is reasonable and what isn't for a Van de Graaff. For me to get over 5 or even close to 10 uamps would be significant considering the value your far larger system achieves (and I bet it is under sulfur hexafluoride (wow, was this first post a funny mistake!)) I can do that for mine (internally only) but the work isn't something I wish to currently perform considering what I still need to do.)

Your post of a real system's actual values tells me a lot about previously published results that simply speculated on their tiny Van de Graaff current. Knowing a viable emitter voltage/current feed also clears up a great deal of confusion for me considering the very few articles that mention this subject at all.

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Dennis P Brown
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Re: Linear deuterium Accelerator-Ion Gun Issue

Post by Dennis P Brown » Fri Mar 25, 2016 1:09 pm

Ordered the rubberized cloth (white; hopefully, non-conducting) for my new belt.

I have a second NST so I will construct a 7.5 kV, full phase and filtered positive supply for my emitter. This should be more than sufficient considering your's.

To play it safe, I am also constructing a 60 ma (max. claim), 30 kV AC flyback transformer system (30-40 kHz) as a possible HV supply for my alternate method to achieve the very HV needed for the accelerator. This will supply my existing voltage multiplier and should achieve the 120 - 180 kV the hard way, maybe. The diodes I have may not support this higher frequency, however. In which case, the 30 kV system still has value.

That is, if the multiplier does fail to achieve the HV due to diode's not handling the high freq, and the flyback system does work (provides the first stage 25 - 30 kV with a current in the 15 - 45 ma range), it can then supply my existing fusor (I do have deuterium gas. Had a registered company # (for SBIR's) when that was still easy to do so took advantage of that.) So constructing this heavy duty flyback system will be worth the effort (again, total cost for this system will be under $100 so in the event of failure, limit my loss. I am able to keep the cost low because: 1) I already have a 15 - 30 volt, 60 Hz, 30 amp power supply for the 2) new, very inexpensive, converter (used to up the 60 Hz frequency to the required 15 - 70 kHz the flyback requires) and 3) the flyback was rather inexpensive.

Finally, as a back up to the back up plan (lol), I did order more of the inexpensive 20 kV diodes just to be ready to try adding more stages to the existing multiplier system; however, that is very iffy with a 60 ma NST (which will not deliver 60 ma under any real load.)

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Re: Linear deuterium Accelerator-Ion Gun Issue

Post by Dennis P Brown » Sun Apr 10, 2016 6:39 pm

Well, not much is currently being posted in this section so I will give a short update on progress (or lack there of); the diodes arrived and I have all required HV caps. So could add three more stages to the voltage multiplier (VM) if I desired. Also, have the flyback transformer (allege 30 kV, 60 ma capable - right; give that claim a big laugh) but I still need the 20 volt 60 Hz to 50 KHz converter I ordered. That should get here this week. Will be interesting to see if that works as stated; the unit is just too inexpensive to believe but have been surprised before.

Once I have that converter (I have a big low voltage transformer that can deliver 20-30 volts at 30 amps +, so the converter will have its required power; not that the device needs more than an amp or two), I can then use my existing voltage multiplier system (four stage) to get in the range of 180- 240 kV (very unlikely to get near that high end value but anything over 120 kV would be overkill, anyway so, just hoping.) Since I do not want to increase the voltage multiplier stages due to the extra work (especially the mounting issues requiring oil to work properly) - besides, if the flyback works even close to the mid values, further stages would be a waste of time and just lower the current resulting a less powerful accelerator, anyway.) So, best to wait for the freq. converter so I can test the system (and avoid useless project building.)

If that does not work, then I will add two extra stages to the multiplier and see what voltage the NST will achieve.

Also, even if the flyback/VM system does work I will still test the flyback at some point (no voltage multiplier attached) to see if it can get in the mid to high 20 kV range and output at least 20 -35 ma (seriously doubt the 40 - 60 ma is even possible. The flyback just looks far, far to flimsy to operate anywhere near that level no matter what the company claims.) However, if it does get mid-20 kV and over 20/25 ma then for under $100 it would be a worthwhile experiment; better still, supply my fusor with a higher wattage power supply (current supply is a 28 kV, 15 ma unit - barely acceptable.)

The rubberized cloth company didn't send the proper piece so need to redo that order; so the Van de Graaff project continues to wait.

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Re: Linear deuterium Accelerator-Ion Gun Issue

Post by Dennis P Brown » Fri Apr 22, 2016 1:11 pm

Quick update.

Had issues with my low voltage, high current DC power supply. Had to gut it and isolate the transformer; then install a diode bridge.

Will have to now use a Varic to control the voltage but at least that power supply does appears to be working again (complex systems do tend to fail as they get old... .)

Hope to test my high voltage flyback transformer this weekend using this power supply with my my new high frequency converter. Be interesting to see what voltage I can get and possibly, measure the current.

If time permits, I guess I will test one of my high voltage diodes to see if it can handle a full 15 kV without failure. If so, maybe test my voltage multiplier to see if the diodes can handle the very high frequency ... be surprised if they do.

Should be a fun, but hopefully not too exciting weekend (as in blown diodes!)

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Dennis P Brown
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Re: Linear deuterium Accelerator-Ion Gun Issue

Post by Dennis P Brown » Sat Apr 23, 2016 8:07 pm

Wow - a first for me; the high frequency converter had its caps (2) blow up in my face. Guess the DC polarity matters (it is not marked so I assumed it didn't matter - wrong.) That hurt (the debris hit hard even those caps were small)- even at twenty volts the power supply can delivery 4 amps but its ripple cap (for the diode bridge I put in) is 6000 mfd and stores a lot of power. Guess I need a new on (another two weeks to wait.) Really should be marked if it matters but cheap is cheap for a reason, I guess.

The up side is my new power supply works (too) well. It can deliver 20, 40 or 60 volts DC of either polarity. Since it was junk, got it for a few bucks (new, likely over $1000) but I just gutted the electronics (too complex to bother with); installed a new bridge and wired some outputs myself.

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Dennis P Brown
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Re: Linear deuterium Accelerator-Ion Gun Issue

Post by Dennis P Brown » Mon Apr 25, 2016 9:40 am

Guess I will add a few images for fun. First photo is of the destroyed Freq. converter - one of the two removed blown caps is shown on it side. I think the device needs a proper ground and lack of one allowed the voltage to exceed the rated value of 30 v DC; the power in my ripple cap was just too great so once the voltage margin was exceeded, boom. The last pic is of the PS with both the freq. converter and flyback installed. Hope to get to this point again and actually get it to work properly. Amateurs often learn the hard way and lucky this didn't endup with an injury - respect caps even at low voltage!
Attachments
MVC-022L.JPG
Destroyed Freq. Converter
MVC-021L.JPG
Original Micro-electronics
MVC-020L.JPG
Power Supply Panel (stripped)
MVC-019L.JPG
Current PS (no flyback/Freq. Converter)
MVC-018L.JPG
Future 30 kV Power Supply

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Dennis P Brown
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Re: Linear deuterium Accelerator-Ion Gun Issue

Post by Dennis P Brown » Thu May 12, 2016 10:43 am

Learning from mistakes is slow! Also, doing the reverse engineering to figure out what went wrong and researching the issues discovered takes a lot of time for the electronic illiterate ... . So, as I discovered the hard way, turns out that grounding one side of the transformer and not the diode bridge results in floating the potential of the diode bridge and having the device using the bridge see an "effective" double voltage that a meter does not "see" - end result: burned out ZVS by exploding all caps; also, didn't realize my voltmeter was both low (for reading DC by 25%!) and only reading RMS on the AC side (a new meter does not have either issue.) Result - again, blew up the caps on a new ZVS system.

So, I am again rebuilding the DC 0 - 60 volt (pos)/high current system using these lessons learned - also, the unit will now have a built in voltmeter so I can read applied voltage in real time; further, I decided to install an internal Variac to better allow the system to be controlled accurately and free up the larger variac for other experiments (the non-exploding cap type.)

Most older hands here will be amused by this method of electronics development, no doubt.

Once the new ZVS arrives will try again and hope to avoid exploding caps. If I get this ZVS driver system to work I hope to then try using this to get the well over 100 kV with a voltage multiplier ladder I already have successfully constructed (the 30 - 45 kHz 20-40 volt AC output system will power a flyback for the 30 kV AC I need). Takes 15 days to receive a new ZVS - so, now on my third one already but believe I have discovered/fixed all issues ... . Learning electronics by building devices and experimenting isn't fast - it is effective if one ignores the rather dangerous exploding caps!

On the Van de Graaff front I have obtained the silver epoxy I require - guess I will try and create a belt that has narrow metal strips (horizontal) on its outer face along its entire length to better charge the upper sphere. Hope this approach results in a better total charge.

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