Spellman DXM70N600X3547 power supplies on ebay -70kV 8.56MA

This forum is for specialized infomation important to the construction and safe operation of the high voltage electrical supplies and related circuitry needed for fusor operation.
Joshua Guertler
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Joshua Guertler » Wed Jul 05, 2017 8:57 pm

What type of rectifier did you use to get the power to DC?

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Trent Carter
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Trent Carter » Tue Aug 01, 2017 2:09 am

I have two of these and I was considering running them in parallel to double the current from 8.5mA to 17mA.

I have a decent array of HVR-1X 3 Diodes. They are rated at 12kV 500mA each in an array of 16 per string. They were on PCBs to rectify 125kV.
Here is what I was considering:

DXM-1 ---- 16x string of HVR-1X 3 ------|
>>>>>>>>>>>>>>>>>>>>>>>>>>>|------330 kOhm @ 100W -------Fusor Cathode
DXM-2 ---- 16x string of HVR-1X 3 ------|

Or I can split the ballast

DXM-1 ---- 16x string of HVR-1X 3 ----126KOhm 100W Ballast--|
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>|---------Fusor Cathode
DXM-2 ---- 16x string of HVR-1X 3 ----126KOhm 100W Ballast--|

Last option, a series parallel ballast:

DXM-1 ---- 16x string of HVR-1X 3 ----63KOhm 100W Ballast--|
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>|---80kOhm 100W ballast------Fusor Cathode
DXM-2 ---- 16x string of HVR-1X 3 ----63KOhm 100W Ballast--|

Do you think I would be safe? Safe = Not damage my new DXMs.

Peter Schmelcher
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.56MA

Post by Peter Schmelcher » Fri May 04, 2018 8:41 am

Using Andrews connector autopsy as a starting point I printed a Claymount style HV connector in PLA.

It’s a work in progress but basically you cast silicone between a PLA shell and the HV cable to eliminate any air voids between the cable and the shell.

The HV connector plug has a 0.5degree taper so all the o rings engage together for the last 2cm of insertion. I only used ¾”ID x 15/16OD silicone o rings and varied the notch diameter for a good fit.

I printed with a 0.4mm diameter nozzle and 0.15mm layer thickness. The walls are 0.8mm thick (two nozzles diameters).

The STL files are about 16meg because of the printed 0.75mm pitch threads. I can't attach the .stl files to my post so PM if you want the stl files.

I fit tested the connector on both of my Spellman, one is perfect all the o rings engage together for the last 2cm of insertion requiring a pleasing amount of force, and the other is similar but requires excess force, in my opinion. I expect just some grease is needed on the o rings.

HV connector.jpg
Picture 601.jpg
Picture 602.jpg
HV connector.png

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Samuel Low
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.56MA

Post by Samuel Low » Sat Jun 02, 2018 7:16 am

Andrew Seltzman wrote:
Thu Nov 24, 2016 1:42 am
I've compiled the matlab m files into a stand alone program that ramps the supply up to 10kV, it should start ramping up the voltage when executed.
You will need the matlab runtime(free) on your computer to run the program
Get the Windows 64-bit version of the MATLAB Runtime for R2016a
Andrew thank you very much for this MATLAB code. As with all others, I've tried to run my Spellman DXM 30kV power supply but the Java Applet just isn't working. Your MATLAB code runs as it does, but somehow the queried voltage out is still showing me a flat zero... I am not sure why. I have not done anything else except to:

1. plug in the Ethernet crossover cables
2. verify that I can ping
3. verify that I can open the Java applet (but not use it, TCP/IP connection shows a blank and the buttons are non-responsive)
4. proceeded to run your MATLAB code, changing all options in your code from remote to local (because I am doing a direct connection between my laptop and the spellman unit).

I've attached the plot. I don't really understand why it doesn't work, the code seems to be working properly and I am successfully querying information such as the server versions and things like that.

Also, has anyone been able to get the Java applet to work on Windows 7? Seems the manual says it works only for Windows-based OS's up till XP.

Anyway, if anyone wants to get their hands on a CA11 cable that connects from a Spellman HV unit, the cheapest I have found so far is about 300USD (inclusive of shipping), from a company called Varex Imaging in the Phillipines. https://www.vareximaging.com/products/c ... connectors

The contact person in charge of cable sales, email: alina.latayan@vareximaging.com
"Physicists are made of atoms." - Michio Kaku

Andrew Seltzman
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.56MA

Post by Andrew Seltzman » Sat Jun 02, 2018 1:08 pm

I don't see an attached plot, could you upload the plot and the text output printed to the matlab terminal?

It sounds like one of the interlocks is tripped, do you have the proper pins jumpered on the 15pin connector?

The java applet is really old and dosen't work on current OS.
Andrew Seltzman

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Richard Hull
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.56MA

Post by Richard Hull » Sat Jun 02, 2018 4:35 pm

In years gone by, I always thought the world would end when, in a rat's nest of cables within a critical function, one would come adrift or be plugged into one of many jacks that was woefully wrong. Now I am convinced it will end in bad code uploaded from another operating system long ago abandoned, but triggering a set of events that are irreversible instead of just failing to work correctly.

As an old programmer, I have seen things go bad like this as one attempts to fix or update undocumented code written long ago that operated many dangerous "switches and routings" within a complex system.

I laughed at one episode of Big Bang Theory when Leonard asked Sheldon what he had planned for the weekend, as he pulled out a dual floppy drive. Sheldon replied, "I plan on enjoying a weekend recalling and exploring the joys of Windows 95."

Richard Hull
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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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