Spellman DXM70N600X3547 power supplies on ebay -70kV 8.56MA

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

Postby Peter Schmelcher » Wed Nov 23, 2016 8:37 am

Andrew I powered up the supply using the 24V fan idea and my supply works as expected. Low voltage test points are fine plus ethernet is good. The hobbs meter reports 225.9 hours HV On.

I think everyone should inspecting C149 33uF 450V for any signs of venting electrolyte before applying 120VAC!

The capacitor can top is a mechanical fuse that is designed to tear open under failure conditions. The top of mine bulged slightly and leaked. C149 might be the root cause of my damaged unit.

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

Postby Dan Knapp » Wed Nov 23, 2016 12:49 pm

Pin 15 is not available as a spare on the custom version of the supply. See Andrew's Nov 22 post. Pin 15 is an additional interlock input. I need to post a revision of my analog controller circuit to reflect this. It also appears that the other (other than voltage control) inputs cannot be left floating as in my circuit diagram. My DXM is not yet producing HV, but I seem to be making some progress.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Postby Jim Kovalchick » Wed Nov 23, 2016 1:06 pm

Sarvesh,
You need to jumper the interlock pins to proceed. See Andrew's posts and the manual. Nice job getting the applet to run.

Rich Feldman,
You got to the same point I did with getting the applet to start and stall. I did the network settings the same way. I think the only way the applet will run is on an old version of JAVA.

Yesterday, I tried to use an app called Packet Sender to send commands as TCP packets to the unit. As I suspected, I really struggled with the syntax of the strings. You need to know a good portal number, and it seems that Andrew is correct that 50001 will work because I can get return strings back from that portal. My trouble is getting coherent instructions to and from the unit. The app is nice, but it want''s to translate ASCII strings into two digit hex and I'm sure that I am failing miserably at this.

After the holiday, I may try to teach myself enough Visual Basic to try that approach. ...and Kuba, no fair saying that it is the programming language of your grandfather. I don't know how old you are, but probably back before you were born I was entering machine code into an Apple one hex digit at a time because I was too poor to buy an assembler. Visual Basic is seems like a dream compared to that.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Postby Rich Feldman » Wed Nov 23, 2016 8:13 pm

A terminated ribbon cable and PC board header are in hand for my analog control "fixture". Thanks for the reminder about pin 15.

>> Pin 15 is an additional interlock input. I need to post a revision of my analog controller circuit to reflect this.

Thanks for drawing that up, Dan. While you're editing, please consider:

1. Change -75 kV to -70 kV in two places, to match the nominal voltage of DXM70N power supplies instead of their output connectors.

2. Change DB-15 to DA-15 in three places. The letter B was mistakenly carried over from DB-25 in the real RS-232 standard. (Both are D-sub connectors.)
dabcde.JPG
dabcde.JPG (25.31 KiB) Viewed 690 times

3. Add the Zo values (5k,5k,10k) of the three analog monitor pins. That's important for controllers that have analog or digital panel meters, easily calibrated to indicate kV and mA.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Postby Richard Hull » Wed Nov 23, 2016 9:19 pm

Thanks Andrew for the full testing and the full, realized output of a working one of these units. It will be great to see someone use one of these to do fusion. I am a little concerned about the ultra low current capability of the device and whether there is an "auto kill" at exactly 8ma. This was frustrating to the VCU nuclear engineering folks who spent $$$$ on a brand new rack mount 30kv 10ma spellman supply. The moment they started to do fusion, the supply tripped offline. This forced a frustrating reset and re-approach to the fusion threshold. They have now spent more $$$$ for yet another beefier supply.

Super electronic supplies by the best manufacturers seem to auto protect as they hit the honestly rated limit on current and can catch and trip on 15ma bumps and burps in the gas conduction regime. This is one of their most nasty faults and crippling limitations for the amateur fusioneer. I guess we will wait and see.

The one good thing about a home brew HV supply that is metered very well is that there is not current trip point, be the supply a home made switcher or a classic hard-nosed linear type. The human being is in total control and not some engineered safety trip point working in the micro-second or millisecond time frame to shut the entire thing down. The homebrew will take the burps and bumps and the end user will never even see the metering jiggle.

My statement in many FAQs about one absolutely having to have 10ma of current in any HV supply before lower level, detectable fusion begins was a full running, stable, 10ma. Excursions and burps and bumps of 100ma or even more are possible as the user learns to apply the voltage needed to do fusion. The gas conduction regime rules the roost and a sudden strike of the glow at 28kv in a good system can easily draw a multi-millisecond 250ma bump! Your supply can't see this and trip out or you will never get there.

Sound defeatist? It's not me, it is the physics of what we are doing.

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

Postby Andrew Seltzman » 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.
DXM_test.zip
(3.16 MiB) Downloaded 44 times

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
https://www.mathworks.com/products/compiler/mcr/
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Postby Rich Feldman » Thu Nov 24, 2016 8:27 am

Attempted AC power-up was not so successful, but was a good learning experience.

Fuse board silkscreen says F1 and F2, both 10 A 250 V. My PS arrived with F2 blown. The fuse was ceramic, so not easy to judge the category of overcurrent that had made it operate. I used glass replacements.

Special tool 1: a nine-inch extension cord with male and female tab terminals. Allows power-up with full visibility of main board and fuse board. A continuity check, all the way from wallplug end of the IEC cord, showed line and neutral reversed. Spellman would never do that, would they? Problem went away when I substituted a different IEC cord. First cord had been miswired at the factory, before final molding of the connectors. :-(

With new 5 amp fuse at F2, and main board connected, DC resistance measured between wallplug blades was more than 10 k ohms each way. So no DC short circuit. Plug it in. F2 blows instantly, with small noise and light, leaving a couple of fused metal balls visible. I think that indicates a fault current at least a few times greater than nominal fuse value, but probably not 100 A, and certainly nowhere near a metallic short circuit current.

With new 10 amp fuse at F2, plugging in made F1 (as received) blow instantly. It's a BUSS GLH 10, with zigzag-shaped link. Two adjacent narrow points had opened, freeing one whole zig to rattle around in the tube. F2 appears to be undamaged. Did this just demonstrate the difference between fast-blow and very-fast-blow models?

Special tool 2, made decades ago: my "ballasting outlet". A regular duplex grounded receptacle in a regular metal box, with a 3-wire cord and plug for use as an extension cord. Except the two outlet sections are no longer wired in parallel, they are in series. Front plate is marked to show which wide slot is Neutral, which narrow slot is Hot, and which left and right slots are connected to each other. I tested this by plugging in two 300-W halogen worklights & getting dim light from both.

When I powered up the DXM70 with two new 10A fuses, and one 300-W lamp in series, the lamp came on & stayed on at almost full brightness. I forgot to measure the voltage drop across the DXM. Am suspecting a semiconductor problem, though as mentioned before, nothing looks or smells burned.

If the circuit board assembly isn't repairable, I would keep the unit just for the bottom half. Probably no active components down there, just transformers & capacitors and diodes. Connections from the upper half are a bundle of 4 similar black wires, a bundle of 2 similar black wires, and a cable of 5 colored wires to J86 "FIL FDBK". Would building a driver from scratch be much harder than building a turbopump motor driver from scratch, as reported here many times?
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Postby Andrew Seltzman » Thu Nov 24, 2016 5:40 pm

Rich,

As far as possible places for shorts in the supply, check:

CR35 (the rectifier)
Q6 (STW30NM60D mosfet in the PFC system)
Q10 (STW30NM60D mosfet in the PFC system)
Q7 (IRFBG30 mosfet for a flyback converter that supplies power to the digital logic)
C161 (big blue electrolytic)
C160 (big blue electrolytic)
C149 (smaller electrolytic near the 2 big blue caps)

Notes:
Q6 and Q10 are in parallel
C161 and C160 are in parallel(the big blue caps)
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Postby Dan Knapp » Thu Nov 24, 2016 5:45 pm

Thanks to Rich for picking up the errors on my previously posted circuit diagram for an analog control for the DXM. I've corrected the errors on the attached revised diagram as well as added the input and output impedances as suggested. In this revision I've added jumpers so as not have any of the control inputs floating. I have not actually built this yet pending a decision on whether my DXM is working OK and thus whether to keep or return it. At this point I'm still playing with a 9 volt battery/pot divider for the 0-10V inputs.
Attachments
DXM Control Box.pdf
Revision of previously posted diagram
(76.65 KiB) Downloaded 69 times
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Postby Dan Knapp » Thu Nov 24, 2016 5:57 pm

There is a cable with a CA11 connector listed on eBay:
http://www.ebay.com/itm/Claymount-13025 ... SwXeJYL0sI
The seller is asking $400. It has a CA1 on the other end if anyone needs both. The price was lowered from $500, but it is still more than would interest me.
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