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Neptunium's fusor progress

Posted: Sun Mar 24, 2019 11:10 pm
by vince_Darmancier
here are some of my progress since i started in 2008...

all the parts are ready
fusor parts resized.jpg
the hemisphere cut and welded to the flanges

all the parts ready to go ! almost there!
fusor part 2 resized.jpg
Requesting Sir Richard Hull to begin the review?
maybe a quick look at "Neptunium"
May increase the odds of this project well over 10 years in the making coming slowly to completion.
Next week first plasma .. and unless unforeseen event, first fusion by April 15th..
Thank you all for your time and consideration
Vince/ Neptunium

Re: Neptunium's fusor progress

Posted: Sun Apr 14, 2019 2:52 am
by vince_Darmancier
Mandatory self portrait
resized me.jpg
the first plasma . the pressure is 3.4e-3 Torr with 40Kv 7.5 mA power supply
first plasma resized.jpg

Re: Neptunium's fusor progress

Posted: Sun Apr 14, 2019 3:04 am
by vince_Darmancier
no neutron detected so far but i am working on the anode. so it should not be much longer ..,.

Re: Neptunium's fusor progress

Posted: Sun Apr 14, 2019 3:05 am
by vince_Darmancier
image missing

Re: Neptunium's fusor progress

Posted: Sun Apr 14, 2019 3:41 am
by Richard Hull
Very good work and a nice set up to be sure. All the best.

You are now in the plasma club.

Richard Hull

Re: Neptunium's fusor progress

Posted: Wed May 08, 2019 11:22 am
by vince_Darmancier
May 7th 2019, 7:12 pm star mode achieved!
slight increase in radiation upon introducing Deuterium.
The pressure is 3.4X10-4 Torr and i used a Hitek High voltage power supply
set on 40mA and 10Kv. Althought i did not go this high on this video.

This was a first run with a lot more to fix and improve. The wiring on the HV is temporary, the neutron detector need more TLC and the moderator is in the process of being finished.

More work to do but on the right track. ... 442864709/

Re: Neptunium's fusor progress

Posted: Mon Jun 03, 2019 11:18 am
by vince_Darmancier
I have recently acquire this monster unit .
Its a glassman high voltage -60kv 50mA in 5 modules and i was wondering if anybody has ever seen this unit or worked with it?
its seems to be in good working condition however it trip at what seems to be a low current and i am pretty sure it is not suppose to
It may have suffered a bit during shipping . Ihave fixed some broken connections and solder on new potentiometers.
I have contacted Glassman for a datasheet .
Any ideas?
Glassman HV resized.jpg
Glassman HV  top resized.jpg
HV unit help 002.JPG
thumbnail resized.jpg
Glassman responded with disappointing news..
This was custom made in 1987 so no technical support...
It looks like it sat almost never used for 30 years...

Re: Neptunium's fusor progress

Posted: Mon Jun 03, 2019 4:45 pm
by Richard Hull
The real business is done in the lower unit. All the top units are used to get high power, high voltage RF which is fed through the big ugly RF cable out of the unit just above the lower unit.

I bet the lower unit is a giant block of epoxy or other type of polymer with the RF transformer, multipliers,etc., permanently entombed. In the old days this would have been a tank of oil. Let us hope there is no nasty issues with the bottom unit. (carbon tracking, internally)

Negative output is great!

Richard Hull

Re: Neptunium's fusor progress

Posted: Sat Jun 08, 2019 4:18 am
by Rex Allers
I thought I'd share my guesses on the big HV supply. I've been meaning to for a few days but struggled with how to present enough without writing a book.

I've looked at several Glassman HV supplies and I think they tend to share a lot of design concepts. The one I am most familiar with is the ER-Series, much smaller at 300W output. Possibly that is what you have sitting on the bench in the fusor set-up pics.

These are just my opinions, but my thoughts are a good bit different from what Richard has speculated. For one thing, I've never seen or heard of a Glassman HV supply that had potted HV sections. All I'm aware of use open air insulation designs.

As intro to theory, here's a block diagram I drew to show a typical Glassman supply.
Glassman blk diag.png
This is for the ER series but is essentially the same design for other higher power models.

The 3525 is a standard switching mode supply controller chip. These are typically used in the last couple decades. An earlier design like your 1987 unit may use an earlier version like the 3524. These create two digital pulse outputs, out of phase with each other. The frequency of these pulses is constant, probably around 50 kHz. The width of the pulses is adjusted to control the output of the supply.

The switching driver block represents circuits that switch the power in alternating directions across the primary of the transformer. The DC supply block comes from rectifying and filtering the AC mains voltage (with doubling if AC is 115 V). The approximate 310 VDC is what is switched into the transformer primary. The last part of this switching is usually done by a pair of power MOSFETs.

The transformer steps up the 50 kHz pulses of 310 V to an AC output of 10 kV center tapped. The center is grounded so the output is two 5 kVAC lines (relative to ground), 180 deg phase to each other. The 5 kV represents the max supply output voltage. If making lower voltages, these voltages will be proportionally lower.

These two phases and the ground are then sent to a full wave HV rectifier/multiplier that steps up the voltage so that 5 kV in makes the full rated supply voltage as an output.

This link:
has pretty good descriptions of how HV multipliers work.

The number of stages needed in the multiplier is Vout / Vin so for 60 kV out it would be 60/5 = 12 stages.

The block diagram shows sensing for the current through the multiplier and also for the HV output voltage. These signals are typically produced so maximum supply voltage or current produces a sense signal of 10 VDC. These signals go back to the controller for feedback to set the operating voltage and to limit the current. These settings come from the front panel pot settings (not shown as inputs to the controller in the block diagram).

In actual implementations that I am aware of, the current sensing and HV divider feedback signals are actually implemented within the HV multiplier module.

Most of the Glassman models are made in one rack mount box. The HV multiplier section is housed in a plastic insulating box and the rest of the circuitry is on one large board. The feedback signals to the controller chip and also to drive the metering of output voltage and current, plus the input settings of the front panel pots, and any protection shutdown, are all implemented in a number of op amps on the main circuit board.

Here's a picture of the transformer in an ER supply.
ER HV Transformer.jpg

In this 300 W configuration the transformer has two secondary coils on the ferrite core. (Note: The white box in the background is the HV multiplier module.) All the transformers I've seen in Glassman supplies thus far share this same size ferrite core, a square shape about 2.5 inches on a side. In the next model step up of output power, there would be two switching drive sections into two transformers with only one winding on the secondary of each. These two secondaries would be connected just like the two coils on one transformer to make two out-of-phase drives for the multiplier.

--- Now on to what might be going on in your big 60 kV 50 mA supply.

I've never seen one in person but pictures seem to indicate that some implementations put the main controller / driver section in a one box and a big multiplier section in a separate rack-mount box.

Here are some pictures I saved several years back (I think from an ebay listing). The supply is listed as EX040P025 so 40 kV at 25 mA or a max power of 1 kW out.
1 EX main FP.jpg
2 EX main BP.jpg
3 EX multi FP.jpg
3 EX multi FP.jpg (36.55 KiB) Viewed 4267 times
4 EX multi BP.jpg
4 EX multi BP.jpg (46.29 KiB) Viewed 4267 times

So this supply is in two sections and they both have a pair of sockets like on your big supply. There was no picture with the pair interconnected, but my interpretation is that the main box with meters and controls contains drivers and transformers to produce the two out-of phase (max)5 kV signals that are connected to the second section with jumpers. That second section contains the multiplier to produce the HV output. It also contains the voltage and current sense circuits to provide feedback and monitor signals back to the main unit through the small multi-pin connectors.

And here are a couple more pics that show the internals of that 2nd box.
5 EX multi in top.jpg
6 EX multi in side.jpg

I can't say I fully understand it. In the first top view you can see the two inputs feeding with well insulated wire into terminals on the module. The top board has a lot of high voltage resistors, so I assume this is HV sense. There is a lot more of it in what looks like 4 sections, than I expected. Even with the side view I can't see anything that looks like the diodes of a multiplier, but I've never seen one up close to examine the details.

If based on nothing else than the back panel's two highish voltage input sockets (J1 and J2) and the standard-looking HV output socket (J3), I have to assume that this is a HV multiplier section.

Now in your -60 kV 50 mA big unit. That's 3 kW output or 3 times the one above. Your back panel pic seems to have the main top unit removed. To me it seems that if just that top unit was paired with the next-to-bottom unit we would have something very like the ebay pics I just discussed. So my guess is the next-to-bottom unit is the multiplier section and its output (the fat black coax) is the supply HV output.

So we have two more sections in the stack between the main top and the proposed multiplier. There are two wires that I propose are dual phase 5 kV power drive to the multiplier. They seem to daisy chain vertically through these two additional units. Each of these have their own AC mains input. I think these are both making more 5 kV in parallel with the main unit's 5 kV to allow putting more current into the multiplier. If I'm right, I would expect they are taking inputs from the main unit (I guess on those small multi-pin connectors (J1) that are probably the same as the A and B outputs from the controller chip on the main board.

Now, what's in that bottom box. The name of the supply says it is for X-ray. There is a big circular connector with blue insulation. My guess is that connector has 3 internal pins/sockets. This is a negative supply, hence for an x-ray tube cathode. The cathode also has a filament. My guess is one of the things in the bottom section is a current source for the filament -- well insulated for the HV. The front panel controls of this section probably set this filament drive. There is some chance it can switch the HV on or off but maybe not.

The only connection I can see between this bottom section and the supply stuff above it is the thick black cable, which I think is just jumpering the HV output from the multiplier section (next to bottom) into the bottom section. My guess is you can take the HV from the multiplier output and ignore or remove that bottom x-ray section.

Here's a link to a doc I made about making HV cables for use with Glassman supply HV sockets. (Also has a bit of comparisons with Spellman.)

So that's my thoughts on your big supply. This is probably not the forum section where we should be discussing this supply details. If you want to talk more on this subject in the forum it should probably move to a more appropriate section. I'm saving this post locally, so I could repost in another thread if desired.

Vince, if you want to talk more details off-forum, send me a message using the email link in my profile and type in your preferred email addy I'll reply with mine for direct discussion.

This doesn't explain why your supply might be tripping unexpectedly but hopefully isn't far off from describing what you have.

- Rex

Re: Neptunium's fusor progress

Posted: Wed Jun 12, 2019 10:09 am
by vince_Darmancier
Your assessment is very accurate. this unit is built much like the EX040P025 and has very similar features.
The power switch were not operational and both voltage and current potentiameters were damaged durring shipping so i`ve replace them
HV unit help 001.JPG
The general power seems fine for now but i cannot get the HV to power up normally other than mechanically pushing the magnetic contact

HV unit help 005.JPG
That action powers every module and cooling fans. but the current generated keep tripping with the first spark at about 20Kv.
Of course this is the wrong way to do it, but it tells me that this unit might be fully operational if only i could figure out how to power the HV section.
without my hands or a tool in it as much as possible!
I am not sure whats going on my 40kv positive unit has never done anything like that. I also have a 10kv 40mA from hitek that does the same silly nonsense at 10mA...

The lower section is in fact a current limiter and feedback to the top master module. but even without it, it can still trip and shut down the high voltage.
In any case Thank you for your expertise I think i could get this to work eventually after blowing a few dozen fuses, but your help is greatly appreciated, and this is the last obstacle between me and fusion! so i am getting a little inpatient you know! :)