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

Post by William Kelly » Fri Nov 18, 2016 2:32 pm

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 6:26 pm, edited 1 time in total.

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

Post by Sarvesh Sadana » Fri Nov 18, 2016 6:15 pm

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

Post by Rich Feldman » Fri Nov 18, 2016 7:04 pm

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.
All models are wrong; some models are useful. -- George Box

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

Post by William Kelly » Fri Nov 18, 2016 8:05 pm

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 » Fri Nov 18, 2016 8:58 pm

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

Post by William Kelly » Fri Nov 18, 2016 11:17 pm

Andrew Seltzman wrote: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.
Well, Some of the parts that I plan to buy and I think have are only rated for around 30-40kv. Namely the Huntington 2.75" viewport as well as the MDC power feedthrough. Also, my chamber is made out of all solid titanium(if this is of any help). Titanium and steel, i believe, become saturated with x-rays and neutrons at 30kv and they start to diffuse out of the chamber becoming harmful to anyone in proximity. Also if i were to get a higher rated power feedthrough from MDC they cost thousands (literally) more. Those are just some of the reasons. As for the conductors and pins and pairs you speak of I quite honestly have no idea what you are talking about not being well versed in the subject. However, I would like to buy a cable from you(I said 12 feet just in case but if you think less, that should be alright) and if you or anyone else would be able to connect the cable to the MDC ceramic feedthrough for me, for a little extra if you need, that would be great as I am by no means an electrician and have no intention of being electrocuted. Thanks!
- William

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

Post by Dan Knapp » Sat Nov 19, 2016 1:36 am

For the DXM power supplies there is no point in having a cable with more than two conductors since the pins are internally connected as pairs, i.e. C and S are connected internally and L and G are connected internally.
Some of William's comments suggest a level of unfamiliarity such as to constitute a significant safety hazard. I would strongly advise that he find a qualified mentor before proceeding much further. This stuff can be lethal.

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

Post by William Kelly » Sat Nov 19, 2016 2:41 am

Dan Knapp wrote:For the DXM power supplies there is no point in having a cable with more than two conductors since the pins are internally connected as pairs, i.e. C and S are connected internally and L and G are connected internally.
Some of William's comments suggest a level of unfamiliarity such as to constitute a significant safety hazard. I would strongly advise that he find a qualified mentor before proceeding much further. This stuff can be lethal.
Thanks for your concern! I do have a mentor from PPPL (Princeton Plasma Physics Lab). He also told me about such risks. We concluded that I would build the reactor as I was, however, at the end I will hire an electrician to examine the fusor before any operation.

-William
Last edited by William Kelly on Sat Nov 19, 2016 2:43 am, edited 1 time in total.

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

Post by Andrew Seltzman » Sat Nov 19, 2016 2:43 am

Some more notes on the operation of these supplies:

1) The connector is only rated to full voltage when mated, it will likely flash over if you run the supply up to 70kV for testing without a connector installed. Up to 10kV is fine without a connector for sure. The matlab code that I uploaded should by default ramp the supply up to 5kv then back down to 0.

2) You will need to jumper pins 11-12 in the J2 control IO port to enable the interlock for HV output.

3) These supplies may produce an overvoltage error when running unloaded at very low setpoint voltage(<1kV) or when running unloaded and given rapid decrease in set point voltage

4) The supplies that I received were pretty dusty inside, you may want to blow yours out before running it at full output
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William Kelly
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Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Post by William Kelly » Sat Nov 19, 2016 2:51 am

Andrew Seltzman wrote:Some more notes on the operation of these supplies:

1) The connector is only rated to full voltage when mated, it will likely flash over if you run the supply up to 70kV for testing without a connector installed. Up to 10kV is fine without a connector for sure. The matlab code that I uploaded should by default ramp the supply up to 5kv then back down to 0.

2) You will need to jumper pins 11-12 in the J2 control IO port to enable the interlock for HV output.

3) These supplies may produce an overvoltage error when running unloaded at very low setpoint voltage(<1kV) or when running unloaded and given rapid decrease in set point voltage

4) The supplies that I received were pretty dusty inside, you may want to blow yours out before running it at full output
Taking this into consideration, would anyone be able to make a cable with 2-4 conductors and attach it to an MDC ceramic feedthrough(http://www.mdcvacuum.com/DisplayProduct ... 1&g=m61034). Again, I will be willing to cover the cost of the purchase of the feedthrough, the CA11 cable, as well as any assembly, shipping and construction costs one might feel reasonable. Thanks as always!

-William

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