Spellman DXM70N600X3547 power supplies on ebay -70kV 8.56MA

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

Post by Andrew Seltzman »

A number of -70kV power supplies have showed up on ebay:
Spellman DXM70N600X3547 115V-AC 0-70KV-AC 8.56MA Power Supply X3547

The seller sold one to me for $200, and 2 to Conrad Farnsworth for $200ea via best offer, you may be able to get them for a lower offer. The seller has 24 of these supplies for sale. These have negative output and analog/serial/Ethernet/USB control. I would strongly recommend buying one of these while they are available. Don't push up the price for the rest of us by using "buy it now", the seller responds promptly to the best offers and there are plenty of supplies available.

http://www.ebay.com/itm/152315510338?_t ... EBIDX%3AIT


Here is the product manual:
http://www.spellmanhv.com/Products/DXM
Last edited by Andrew Seltzman on Sun Nov 13, 2016 9:08 pm, edited 1 time in total.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Grigory_Heaton »

Damn that's a good deal. Shame I can't justify the cost at this point. Congratulations to anyone that picks one of these up.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Kuba Anglin »

Can you verify the HV connector type? I know these units sometimes have specialized connectors and it is difficult to tell by the picture.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Jim Stead »

In a previous post, Andrew said they used a Claymount CA11 mini connector. See viewtopic.php?f=6&t=10294&p=70621&hilit ... 547#p70621
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by William Kelly »

Update: I just purchased the last one, also for $200. Thanks for letting us know about this! What a snag!
- William
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Dan Knapp »

I just purchased one also. They went quickly. Thanks Andrew for letting us know about these.
I checked the National Instruments web site to see if there was a LabView driver for this power supply posted, but there doesn't seem to be one. If anyone has or plans to write one, it would be nice if it was shared with others here.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Andrew Seltzman »

Here is a matlab driver I wrote for the supply, It should ramp the supply up to 5kV over 5 sec, then back down to 0v
Attachments
DXM-control.zip
(1.75 KiB) Downloaded 715 times
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Rich Feldman »

Thanks for the tip, Andrew, and for suggesting that readers avoid the BIN button. Reminds me of those $99 turbopumps that came up on ebay a few years ago. One has to wonder what fraction of the sales began at this forum.

I am among the fortunate buyers.

Just discovered that ebay's Offer History page shows more detail when one is logged in.
We can see which offers expired without a response, and which ones were countered by the seller.
Capture.JPG
The only money value shown is mine.

I admire Andrew's finely tuned ebay searches. He spotted and announced that set of three "Hc-3" detector tubes a few weeks ago, which (by coincidence) I had stumbled upon and was exchanging messages with the seller.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Andrew Seltzman »

Bern Bareis actually tipped me off to these supplies. Did you end up buying those He3 tubes?
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Jim Kovalchick »

I picked up one of these too. The manual has lots of good info on how to use various interfaces and how to create your own software controls like Andrew has done.

I hope everyone's units comes through in good shape. I probably won't tinker with mine until I'm back at our lab in York PA and Mike is home on break. I'm assuming the biggest challenges will be rigging up an alternate connector and dealing with arc tripping of the supply when new grids arc and spark during burn in.

I recommend that people add a kill switch at the interlock pins.

Many thanks to Andrew for his insights on these. I saw these show up on Sunday in my normal followed searches, but I resisted the urge to BIN until I did some research. A forum search showed that Andrew had one. Not only did Andrew answer my quick questions, but he saved me a couple hundred with a recommendation on the buy it now price. :)

If folks have operating experience I hope they share here.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by William Kelly »

Jim Stead wrote:In a previous post, Andrew said they used a Claymount CA11 mini connector. See viewtopic.php?f=6&t=10294&p=70621&hilit ... 547#p70621
Does anyone know a way of acquiring one of these CA11 Mini Connectors? I reached out to the company and the eBay seller, unfortunately for me, Claymont only sells to companies and apparently a 16-year-old kid does not qualify as a company. But in all seriousness, if someone knows anything about where to get one of these it would be much appreciated. Thanks!
- William
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Rich Feldman »

We can make them, William. What kind of HV insulated cable will you use? Which of the four terminals in the negative HV connector well do you want to connect to? So far I've been unable to find a dimensioned drawing of any CA11 connector, so I will measure & report when my PS arrives. I will want to bring out at least two of the terminals, for filament power on x-ray tubes at modest voltage (30 kV?).
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Andrew Seltzman »

Here are the dimensions of the connector, I'll work on a better drawing later
IMG_20161113_201038032.jpg
Designed to be used with this wire:
http://hvstuff.com/1meter-100kv-35kvac- ... e-stranded
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Andrew Seltzman »

Here is an autopsy of one of the CA11 connectors, the plugs are potted and not available as a kit.
IMG_20160801_152630113.jpg
IMG_20160801_152622788.jpg

And the progress in replicating it:
SAM_5224.JPG
IMG_20160726_175654570.jpg
SAM_5226.JPG
Flyer Connector CA11.pdf
(134.48 KiB) Downloaded 1988 times
The pins are 2mm diameter, 22mm long with an 11mm insertion depth. Not all of that depth goes into the mating socket because of the potting compound and a silicon gasket
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Peter Schmelcher »

Andrew I also snagged a supply and I just wanted to say thanks for the tip.

Nice work on the replacement connector! When I located the CA11 specifications in medical connectors I thought to myself buying new ones are going to hurt.

I can’t tell from your autopsy picture of the CA11 if any of the 4 wires are in good electrical contact with the black rubber. I am guessing the black rubber is mixed with carbon and is slightly conductive to reduce the maximum E field gradient within the connector/cable dielectric.

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

Post by Andrew Seltzman »

The center wires are insulated but wrapped in a slightly conductive anti-corona liner. The outside of the cable, starting after the potting epoxy, is wrapped in the same liner under the metal ground braid.

Claymount quoted a 2m cable with a CA11 connector at about $60
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Jim Kovalchick »

Andrew and anyone else,
Do you know if the 600 Watt rating is based on a hard current rating at every voltage, or does the power rating mean you can drive a higher current at lower voltages than you can at rated voltage?
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Andrew Seltzman »

Hard current rating, max is 8.56mA
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Peter Schmelcher »

Andrew another thanks.
For $60 I am happy to buy a CA11 pre connected to a cable. I was expecting sticker shock around medical related stuff and had begun looking for materials to build my own. I guess I need to be more open minded.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Dan Knapp »

Perhaps given the number of these supplies purchased, we should consider a group purchase of cables.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by William Kelly »

Rich Feldman wrote:We can make them, William. What kind of HV insulated cable will you use? Which of the four terminals in the negative HV connector well do you want to connect to? So far I've been unable to find a dimensioned drawing of any CA11 connector, so I will measure & report when my PS arrives. I will want to bring out at least two of the terminals, for filament power on x-ray tubes at modest voltage (30 kV?).
Yes, that would be great if you can make one. I have a spherical vacuum chamber as well with 2.75" ports. I am getting a high power MDC feedthrough (http://www.mdcvacuum.com/DisplayProduct ... 1&g=m61034), if you need this info. So I would like a CA11 chord of adequate length probably like around 12 feet or so.
EDIT: I would also like to add that I have little to no knowledge about the chords needed for this power source. The extent of my knowledge is that: I need this power source to transfer at the very minimum around 35kv to the vacuum MDC feedthrough. So what I need chords for are: firstly, from the plug on my wall to the power supply next from the power supply to a computer as that is how you control the output I believe and then finally from the power supply to the MDC feedthrough on the vacuum chamber.
Last edited by William Kelly on Fri Nov 18, 2016 1:26 pm, edited 1 time in total.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Sarvesh Sadana »

I also picked one of these supplies.

If anyone is considering doing a group purchase of these connectors, count me in.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Rich Feldman »

Re. cables with CA11 connector:

A group purchase can overcome hurdles like minimum order value, or institutional-byuer requirement. But there are important product variables other than length. Experienced users like Andrew might have good suggestions there.

How many inner conductors do you want? I need at least two. Do cables from Claymount always come with four? I have not looked at the DXM70N manual to see how the CA11 receptacle is wired.

What about the connector's ground ring, and possible braided conductor outside the cable's HV insulation?

What's on the other end of the cable? Another CA11 connector? In that case, consider ordering cables twice as long as necessary, and cutting them in half.

What's the maximum voltage you need? Probably not 75 kV DC, the nominal connector rating. Homebrew solutions for fusors could get by with less strongly insulated cables.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by William Kelly »

Rich Feldman wrote:Re. cables with CA11 connector:

A group purchase can overcome hurdles like minimum order value, or institutional-byuer requirement. But there are important product variables other than length. Experienced users like Andrew might have good suggestions there.

How many inner conductors do you want? I need at least two. Do cables from Claymount always come with four? I have not looked at the DXM70N manual to see how the CA11 receptacle is wired.

What about the connector's ground ring, and possible braided conductor outside the cable's HV insulation?

What's on the other end of the cable? Another CA11 connector? In that case, consider ordering cables twice as long as necessary, and cutting them in half.

What's the maximum voltage you need? Probably not 75 kV DC, the nominal connector rating. Homebrew solutions for fusors could get by with less strongly insulated cables.
What I need, at least, is a cable to plug into the output port of the spellman (the CA11 connector) to the MDC ceramic feed through on the vacuum chamber. All the while extreme insulation will be needed due to the nature of 30kv. Also this plug would need to be, at the very least, 12 ft long and able to handle at least 40kv.
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by Andrew Seltzman »

Keep in mind that fusion rate increases exponentially with voltage, if you have a 70kV supply, I'd recommend running 70kV. Any reason why you want 12ft of HV cable? The supply can be remotely controlled, you can mount it close to your fusor and control it at a distance. I believe you can order cable with a CA11 on one end and no connector on the other. For the spellman supply, 2 pairs of the 4 pins are connected in parallel, (HV and fil) and (fil return). Since they pot the cables and pins you probably would want the cables with 4 conductors.
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