50kV Supply

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Chris Giles
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Re: 50kV Supply

Post by Chris Giles »

Joe Gayo wrote: Sat Jan 19, 2019 11:02 am All true.
Excellent work! I appreciate Richard's comment about the diodes not being a limiting factor and also that Spellman would have been designed to have a very low % ripple which is not necessary. Given it is a charge pump circuit i think the factor determining how much power it can supply is the capacitance of the capacitors in the stack (i.e. can be estimated from the charge CV^2/2)

Joe, I'm sure anyone else trying to rig this up would appreciate any further details on the driver and/or the pinout etc of input to the Spellman HV stack, especially for those not so expert.

BR
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Joe Gayo
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Re: 50kV Supply

Post by Joe Gayo »

The multiplier is 10 full bridge stages with 2100pF caps.

Use the excel sheet on this page to calculate regulation and drop: http://www.voltagemultipliers.com/html/multdesign.html

(But in reality I've done the work already, 75kHz drive frequency gives the least voltage drop and maximum power)
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Richard Hull
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Re: 50kV Supply

Post by Richard Hull »

75khz may heat the ceramic caps a bit and reduce the full power duty cycle run times, but it is rare you would need tremendous full power runs.

40kv @ 10 ma is 400 watts. In Tesla work, it was found that the higher the spark interrupt rate, ceramic capacitors would drop in capacitance as the silver deposition (plate electrodes) on the titanate ceramic faces would be blown off in spots, but that arc shock excitement in the primary circuit was horrid and sharp. In a modern switcher this should be less of an issue, but heating is certainly expected in high power filtering at high frequency.

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Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Nicolas Krause
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Re: 50kV Supply

Post by Nicolas Krause »

Thanks for the note about this supply! The price was right, and I picked one up and will hopefully put it to good use with a bit of work in the future.
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Re: 50kV Supply

Post by Rex Allers »

So this HV multiplier is a 50N06 = 300W out.

I have a Glassman ER series 60N05 supply so also 300W.

I'll have to wait to get the one I ordered but I wouldn't be surprised if they are about the same design except 10 multiplier stages for the 50 kV vs. 12 stages for the 60 kV.

Here are some pictures of the 60 KV one I examined.
60kv assy.jpg
60kv inner.jpg
60kv multi board.jpg
I made these notes when I was looking at the innards of the 60 KV multiplier.
-----
Glassman ER60N05 (or) ER60R05 negative

60KV @ 5mA (=) 300W

12 stages so ~ 5KV input (each phase)

all Caps 2000 pF 7.5 KV
room for double (parallel) caps on 1st 6 stages

1st two diodes (ground end of multiplier) are
RVT 1500 -- 15kV, 50mA, 100nS

rest of diodes (46)
apparent random mix of 3 parts
S56A, S57B
and a few S59A

Never found full PN or specs on these diodes
Since these are probably lower rated than the two input diodes,
I'd guess these may be 25 or 30 mA rated.
-----

This doesn't change anything said so far but might add a bit of info.

If Joe is pushing it to 700 W out, that's 700/50 = 14 mA. That would be below my guess of 25 or 30 mA rating for the diodes, but not as much margin as most HV multiplier designs I have looked at.
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Dennis P Brown
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Re: 50kV Supply

Post by Dennis P Brown »

Interesting pictures. Those are tiny caps compared to my 8 stage unit (20 kV/0.1pF door knob caps and 100 ma diodes.) I just used a 1500 volt, 60 Hz MOT so, certainly not in the class of continuous power like those units with their very high driver frequency but certainly my unit was a dangerous bear (a bit too; I ran it to full power all of once before setting it aside.) Quarter power from the P.S. to the stack equaled 45 kV. I still have the breast - it is in a vertical plastic cylinder tube (clear) and was filled with oil (since drained.) If I get brave, I could still revive my deuterium accelerator but just don't have a use for that monster, either. I prefer fusors (which is slated for reconstruction using a new, four-way cross and 70 kV power supply (single transformer - not a multiplier.)
MVC-001L.JPG
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Re: 50kV Supply

Post by Rex Allers »

Dennis, not sure what you meant to type but those door knob caps surely must be a lot more that 0.1pF.
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Re: 50kV Supply

Post by Richard Hull »

I agree! maybe in the nano farad range like .002uf = 2nfd = 2000pf. They are just too big to be .1pf. I don't know if I have ever beheld a .1 pf cap.
Normal capacitance between nearby wires might be in the .1pf range.

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Dennis P Brown
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Re: 50kV Supply

Post by Dennis P Brown »

Oops; you are both correct. I should have typed 2000 pF. Thanks for catching the mistake!
Chris Giles
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Re: 50kV Supply

Post by Chris Giles »

Please could someone let me know if these units come with the High Voltage transformer or are just the HV multiplier? I can't find the pic which Joe posted of it(?). I found the pics which Andrew S posted of a similar complete unit here and that has the HV transformer on the main PCB, not cased with the multiplier.
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Joe Gayo
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Re: 50kV Supply

Post by Joe Gayo »

HV Transformer and Multiplier are included (no driver)
Chris Giles
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Re: 50kV Supply

Post by Chris Giles »

Thanks very much Joe
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Re: 50kV Supply

Post by Rex Allers »

The ebay seller is 'bdmerchandise'. I exchanged some emails with him and he seems pretty helpful if not completely aware of details on all these parts.

I got my unit today (the same aluminum box that Joe told us about). As I suspected, and posted earlier in this thread, it looks to be Glassman parts that are based on their ER series supplys. The multiplier module in these boxes is indeed an ER-series part and the transformer looks to be the one used in ER supplies. The ER series is 300 W output.
They had many options, like this:

ER10P30 ER10N30 ER10R30 0-10kV 0-30mA
ER15P20 ER15N20 ER15R20 0-15kV 0-20mA
ER20P15 ER20N15 ER20R15 0-20kV 0-15mA
ER25P12 ER25N12 ER25R12 0-25kV 0-12mA
ER30P10 ER30N10 ER30R10 0-30kV 0-10mA
ER40P7.5 ER40N7.5 ER40R7.5 0-40kV 0-7.5mA
ER50P6 ER50N6 ER50R6 0-50kV 0-6mA
ER60P5 ER60N5 ER60R5 0-60kV 0-5mA
ER75P4 ER75N4 ER75R4 0-75kV 0-4mA

In those, P = positive output, N = negative, and R = both (I think for R, you had to swap the multiplier module to change between P or N.) In the part numbers, the first number (before P/N/R) is kV and after is mA, so the product of those two numbers is 300 (watts).

The units the seller is striping down, I think, are some kind of big complex security xray scanners. I think this HV part powered a small xray tube.

So it looks to me that Glassman sold some custom design components that is very close to the ER supply.

The seller sent me some pictures and it looks to me that he has boards that are ER main boards, except the place that usually has the transformer on the board is unpopulated and the transformer and multiplier have been moved to this separate aluminum box. I think the board and one of these boxes can be paired to make an equivalent to an ER supply. Not simple... you'd need to figure out how to connect AC -- pots for V and I control (or voltages) -- meters or monitors for V and I -- how to connect between the board and this box.

I have purchased one of these ER-looking boards from the seller but don't have it yet. I think he said he had 8 total units that he is stripping down. I think he might be receptive to selling a package with both this box and one of the driver boards.

I can try to share more about how it looks after I get the board. So far, what I'm sharing here just looks good in theory.

Joe made his own driver for the transformer and says he is getting 700 or more watts out (more than twice the 300 W spec). I'm not sure if it is possible to get that power out of the original ER-style board. At minimum, I think that would take some hacking to the current sense which is an input control to the 3525 switcher chip.

Here's a link to one ER manual that has schematics. All the versions are about the same except for the number of stages in the multiplier and the polarity orientation of the diodes.
https://docs.google.com/file/d/0B7IIDFX ... xXTDg/edit

Hopefully I can add more after I get the board. If you contact the seller, tell him Rex

sent you.

-Rex
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Chris Giles
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Re: 50kV Supply

Post by Chris Giles »

Thanks Rex. That is most helpful, particularly the manual. The other manuals I have found have been similar but that one is exactly the right model (board part number matches). Looks like a complete unit could be re-created but would be quite a fiddle.
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Joe Gayo
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Re: 50kV Supply

Post by Joe Gayo »

Revised my driver. The frequency is lower(30KHz) and the peak switching power is around 1200W. The multiplier and transformer are quite robust in the Glassman stack. The new combination has my device around 1.5M n/sec at near full voltage/current.
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Re: 50kV Supply

Post by Cristiano_Machado »

Hello,

Finally I received my unit. Now I am working on the driver.

I would appreciate your comment on my design. This is based in Joe's suggestion (http://www.loneoceans.com/labs/sstc2/), and Gao Guangyan's project.
Power inverter
Power inverter
The output will be plugged into the unit transformer.
Transformer
Transformer
I am still working on the frequency generator to control the IGBTs.

Thanks for the help.

Regards,

Cristiano
Chris Giles
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Re: 50kV Supply

Post by Chris Giles »

HI Cristiano

I recommend that you purchase one of the control boards from the seller and use that as a start. Coupled with the HV box it makes a complete Glassman ER PSU minus the front panel components. It has a driver similar to your sketch. You can start from that and then try to hack it to get higher output.

If you choose not to, you can still refer to the schematic for it. Regarding your schematic, you should use a bridge rectifier, and also you would not need a Variac if you use a standard PWM controller/driver IC where you have shown "frequency driver".

Regards
Chris
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Re: 50kV Supply

Post by Cristiano_Machado »

Hello Chris,

Thank you for your feedback. I will check this board with the seller.

I completed the schematic, using my initial design. Now I need to figure out the value of interrupter's resistors and capacitor. I think 25 kHz and 40% duty cycle is a good start and it will not stress the unit.

Please fell free to comment and give any suggestion.

Regards,

Cristiano

Controle complete.jpg
seamus sullivan
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Re: 50kV Supply

Post by seamus sullivan »

how many mA should the 50kv transformer be rated at?
im a still learning and planning on building my own fusion reactor.
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Re: 50kV Supply

Post by Rex Allers »

Seabird, your two first posts seem very uninformed and possibly troll-like, but I won't give any details why until you fix things to become a valid user.

(Posting my new-user reply again.)

When you registered you clicked to accepted the terms that were given on the 1st registration page:
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viewtopic.php?f=47&t=10508#p69690

and specifically The Rules: #1
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Mark Rowley
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Re: 50kV Supply

Post by Mark Rowley »

His question is also not pertinent to this thread and furthermore the answer he seeks is easily found in the FAQ's. Providing he complies with the registration rules, answering his question will serve to skew / hijack the linear flow of Joe's post.

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Re: 50kV Supply seamus sullivan

Post by seamus sullivan »

ok sorry
i have fixed that and put in my real name and my about me.

what should my power supply be rated at?
how many mA and kv should it be set at?
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Richard Hull
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Re: 50kV Supply

Post by Richard Hull »

Fusion power supplies are not set at any voltage or current. Instead they must be totally variable from 0 volt to a maximum determined by the user. Demo fusors are easily run by oil burner ignition transformers controlled by a variac. They are typically rated at 10kv @ 20 to28 ma. A neon sign transformer is more often used in the 12kv to 15kv range and rated at 30ma. High voltage diodes are needed to turn this into DC.

All of this related to a demo fusor is in the FAQs which it is now obvious you have not read at all. Demo fusors do not do fusion....

Serious, real fusion fusors demand a minimum of 30kv @ 30ma capability or more. This separates the men from the boys. Top level fusors use supplies that are capable of running well over 40kv @ 30ma.
Again, all of this is in the FAQs....Read them....

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Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: 50kV Supply

Post by seamus sullivan »

ok thanks for your help. i will read the FAQs. I just recently registered and don't know a lot about the site.
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Nicolas Krause
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Re: 50kV Supply

Post by Nicolas Krause »

I've finally gotten around the opening up my Glassman 50KV supply, and was reviewing this thread before beginning the conversion work for my fusor. Unfortunately a number of photo links in this thread appear to be dead, I was hoping Joe had some backed up and would be able to repost them!
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