Spellman DXM70N600X3547 power supplies on ebay -70kV 8.56MA

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Peter Schmelcher
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Peter Schmelcher » Sat Jan 28, 2017 8:15 am

Purchasing a connector is not looking so good.

I was ready to buy the $160 part but then on Friday they had cold feet. I think it was because I was the end user and paid all taxes.

So don’t hold your breath and get ready to make your own HV cable termination.


BTW I measured the filament waveform (no load) thinking it might be useful as a floating power supply for a mass flow controller or something.

The waveform looks like the output of a pulse transformer. You get a positive +20V pulse then some time later a -20V pulse. A faster pulse rate is a higher filament current.

-Peter
DXM filament.JPG

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

Post by Trent Carter » Sat Jan 28, 2017 5:32 pm

I was also thinking about the filament power supply. I would not use it for mass flow devices because they generally need 24vdc and those supplies are cheap and readily available.

However the filament supply is unique in the fact it is on the -70kV side of the supply, thus Spellman has performed the necessary steps to have a low voltage, high current supply that can operate at the -70kV potential. Thats non-trivial for most. So I was thinking of using the filament supply as intended; to drive a filament. Seems like a easy supply for the hot filament of an ion source. Assuming the ion source was implemented near or inside the cathode. I don't have any brilliant ideas on any such implementation at the moment, but have added it to my mental toolkit.

As for the cable; I just ordered one directly from Claymount (now Varex) for $170 +S&H+Tax. Yes, almost as much as the supply. I too got cold feet on ordering two, and grabbed some decent HV connectors and a nice cable from HVStuff to see if I have the skills to contain 70kV (likely not).

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Garrett Young
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Garrett Young » Thu Feb 02, 2017 3:07 am

Andrew,

I attempted a HV cable and it arcs at about 28kV to the power supply case. Any chance I could buy a single conductor 2.5 ft cable assembly from you?
- Garrett

Andrew Seltzman
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Andrew Seltzman » Tue Feb 07, 2017 5:43 am

I don't have any complete cables for sale, but I do have a cable plug. You would have to pot in you own HV cable with an RTV silicone and buy the required pins. Send me an email at seltzman <at> wisc.edu

I might be willing to do a mass production run of cable plugs if there is interest.
Andrew Seltzman
www.rtftechnologies.org

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

Post by Trent Carter » Mon Feb 20, 2017 9:43 pm

I fabricated a physical controller for the Spellman supply, thought it would be a one day job, but took two. The main snags were;

1. The pin 11 - 12 that is labeled "X-Ray Enable" is the interlock (no big news there)
2. Pins 15 and 12 must also be connected but only after 11 and 12. So if you wire them to one switch as I did the power supply won't enable HV out.
The rest was straight forward.
Other notes;
3. If you want to get +10V from the Spellman to simplify your controller, you have to turn the tiny trim pots on the front of the supply all the way to the right, then you will have +10 V on pins 5 and 7

For real use I don't need this controller but for development and testing nothing beats a knob and switch. For automation reasons I will be using the rs232 and/or TCP for remote operation. During "Oh C4@p" moments I prefer not to have to fumble with a mouse and keyboard. I love slap-off switches and paddles as you can see. I had one 1.5kV supply go "fireworks" on me this week and I paddle-shutoffed the impending fire.

You can also see the controller I made for my 30kV Bertan Series 106 (smaller brown controller with one LCD) has been a good workhorse.

*A special thanks to Andrew and Dan Knapp for publishing every detail; it saved me a few hours I am sure.
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Richard Hull
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Richard Hull » Mon Feb 20, 2017 9:55 pm

It really helps when those of us who know electronics and computer interfacing can kludge stuff together to make dead things "go" again. Help from friends who have trodden the path saves us time as well. We share back what we have learned. This is what open source means in our unwritten constitution.

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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Garrett Young
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Garrett Young » Thu May 04, 2017 2:59 am

I purchased a known defective Spellman DXM70N600X3547 and the inverter board was completely gone (especially since someone previously attempted to fix the board). I designed a new inverter specifically for DXMXXX600 supplies with a user selectable switch frequency (20-80kHz). When you remove the user control interface and power factor correction front end the driver is really straight forward. I used a current transformer to limit the peak primary current in the flybacks on a cycle by cycle basis. The feedback loop reuses the monitor cable from the high voltage board and controls the PWM duty cycle based on output current. I power the circuit using a variac for easy control and limit the power to the flybacks/multiplier in order to protect them from thermal overload. I was easily able to achieve 500k n/sec on it's first run (35kV @ 8mA).
IMG_1597.JPG
- Garrett

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Richard Hull
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Richard Hull » Thu May 04, 2017 8:31 pm

There is always a way to "skin th' cat". It just takes know-how and a will to do and accomplish. The hands-on-imperative.
Good work!

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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Rich Feldman
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Rich Feldman » Sun Jun 18, 2017 3:49 pm

Nice work there, Garrett. Good reference in case my repaired DXM70N600 fails to work. So far, it's never failed because it's never been tried (since repair).

Sounds like some of us are in a club which enjoys the Frankenstein approach to re-animating old subsystems.
Long ago I acquired up a Kaiser HVPS rated for about 1200 V at 1 A for about $35.
Figured its inverter could be connected to a different transformer, such as one of several already on the shelf.
Mike echo oscar whisky! I repeat! Mike echo oscar whisky, how do you copy? Over.

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Nick Peskosky
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Nick Peskosky » Thu Jun 29, 2017 5:44 am

It's been a while since I have been able to chime in on this thread but I was lucky enough to score one of these supplies while I was deployed most recently over in Japan. Cobbled together a breadboard analog controller over the weekend and was able to make this supply come to life (confirmed with a trusty Fluke 80K-40) tonight. I missed the notes on the trim pots at first and couldn't get an output on the HV side. Measured my 10kOhm pot and realized there wasn't a dc voltage on the rail so I just subbed in a bench DC supply at a regulated 0.8V to realize -5.00kV on the output. I'm working a few upgrades to my existing Fusor and simultaneously commencing work on a second 6-way cross that I hope to turn into a BoT system. This thread has been absolute life saver as far as reference materials go!

I'll provide an update once my crossover cable arrives from Amazon.
Spellman DXM70N600X_Test_06.28.2017.jpg
Nick Peskosky
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"The whole of science is nothing more than the refinement of everyday thinking." - Albert Einstein

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