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 » Fri Jan 13, 2017 2:41 am

Andrew

I am waiting for a quote from Claymount for both the part numbers you mentioned.

The web page product inquiry email address for North America is:
Philippines.Claymount.CS@vareximaging.com

Do you have a different contact address?

-Peter

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

Post by Andrew Seltzman » Fri Jan 13, 2017 2:57 am

My sale's contact was:
Karen Albright
email: Karen.Albright <at> varian.com

If you were being quoted through a different division, particularly an international one, they might quote a different price.
The 40 days lead time on the cable sounds correct, they quoted the same lead time to me.
Andrew Seltzman
www.rtftechnologies.org

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

Post by Peter Schmelcher » Fri Jan 13, 2017 4:25 am

Thanks. Just sent an email with fingers crossed.
-Peter

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

Post by Garrett Young » Sun Jan 22, 2017 7:58 pm

Andrew,

The price you were quoted was given as a "one-time, educational institution courtesy".

What contacts are you using in your replacement connector?
- Garrett

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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 Jan 23, 2017 3:52 am

I bought two of these units from the same eBay seller [ntc_tech]. The main difference was the fact they were listed as [For parts or not working] and it was true; both broken as expected..

I have both up and running and bench tested to 5k volts. I have been unable to get a response on the HV cable so I can't test them at full throttle.

Thanks to Cliff S. and his generous contribution in time and sharing partial schematics the repairs went like this.

Unit Serial Number 411: (showing 13.8 hrs)
Replaced Q11 and Q8 [IXFH26N50] Symptoms: showing shorts on all 3 pins.
Replaced Q10 [65F6110] Symptoms: showing shorts on all 3 pins.
Replaced C149 (working and tested OK, but slight bulldog in top, you know how sensitive CAPs are to heat and they will fail eventually)

Unit Serial Number 341:
Replaced Q6 and Q10 [IXFH26N50] Symptoms: showing shorts on all 3 pins.
Replaced C160 and C161 (preventative maintenance, they tested fine)

Time:
Learning schematics and finding physical PCB part locations: 1 hour
Tracking down faulty components with Fluke meter: 1hr on first unit, 30minutes on second due to learning the layout.
Desoldering and verifying parts were defective: 30minutes (20 of which was switching to leaded solder so i could actually get them desoldered)
Ordering components: 30min all Mouser
Replacing faulty components: 30min.
=========
Total: 3 hrs for 2 units, or 1.5hrs / unit.

Cost ~$57 for two units. I actually used one MOSFET from unit 341 in 411 that I switched out both so they would match, but then found the same component bad in the other unit that I missed at initial debug. Thus I had one extra part, and needed it.

Shopping List:
C160 and C161
Mouser #: 5985-450V150
Mfr. #: 381LX151M450K022
Desc.: Aluminum Electrolytic Capacitors - Snap In Aluminum Electrolytic Capacitors - Snap In 450V 150uF 30X30
2 $3.80 $7.60

C149
Mouser #: 667-EEU-EE2W560
Mfr. #: EEU-EE2W560
Desc.: Aluminum Electrolytic Capacitors - Leaded Aluminum Electrolytic Capacitors - Leaded 56uF 450volts AEC-Q200
2 $3.26 $6.52

QQ8 and Q11
Mouser #: 747-IXFH26N50P
Mfr. #: IXFH26N50P
Desc.: MOSFET MOSFET HiPERFET Id26 BVdass500
2 $5.91 $11.82

OEM Fuses - Ceramic + extras
Mouser #: 576-0314015.HXP
Mfr. #: 0314015.HXP
Desc.: Cartridge Fuses Cartridge Fuses 250V 15A Fast Acting
10 $0.744 $7.44

Q6 and Q10
Mouser #: 726-IPW65R110CFDA
Mfr. #: IPW65R110CFDA
Desc.: MOSFET MOSFET N-Ch 650V 31.2A TO247-3
2 $8.22 $16.44

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

Post by Garrett Young » Mon Jan 23, 2017 4:16 am

Trent,

Nice! What do you plan on doing with 2 supplies?
- Garrett

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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 Jan 24, 2017 1:39 am

I have 3x operational HV supplies
Bertan 30 kV @ 33mA (older analog Bertan 106 3040)
2x Spellman 70kV @ 8.56mA (DXM70Ns)
This will give me flexibility to have 70kV @ 17mA. I also want to do some testing of direct conversion even if just simulated but thats beyond the typical fusor applications. I also wanted to make sure I ended up with at least one working supply, so buying two increases my odds of success.

I really like the fact I can completely automate these supplies via ethernet, RS232, or USB. I realize a simple DAC will automate even the older analog supplies, but repeatability and remote-control are two features at the top of my wish list and these supplies are perfect for both.

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

Post by Dennis P Brown » Wed Jan 25, 2017 1:23 pm

A word of caution on supply ratings; a power supply that has a 70 kV rating and has a max current of 8 or so milliamps does not generally mean it can supply both at the same time. You might want to check what the supply can do before counting on this type of performance. Critical is the power it can supply within the 25 - 45 kV range.

Also, using two supplies simultaneously is very difficult due to issues of impedance matching and ground loops. Be careful trying that with a fusor since resistance can jump all other the place and balancing load is, as a result, tricky.

Your 30 kV, 30 ma supply does appear to be a good unit for fusion (again, assuming it can handle close to that current in the 25+ kV range.)

I am curious to know what you mean by "direct conversion"?

Finally, your repair of those units is impressive and I am sure you will get good results once you start with your project.

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

Post by Bob Reite » Thu Jan 26, 2017 9:50 am

Putting two supplies in parallel can be tricky. However if they are both the same make and model and each has its own ballast resistor (to help balance the load evenly) it can be done. You might also consider putting a diode in series with the output of each, but they would need to be 80KV PIV diodes and you would have a roughly 150V drop across each diode.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.

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

Post by Trent Carter » Thu Jan 26, 2017 5:04 pm

Dennis:
Yes; 70kx @ 8ma spec != empirical. As Ronald Reagan used to say; Trust But Verify. They are what they are, and I am not trying to save the world, so if they under-perform, I will have to accept it as fact or buy new supplies.

As for direct conversion, I am referring to directly converting energy from a fusion device into electric potential. Not suited for D-D, but for p+-B11 (and others). It is really the holly grail since it has high theoretical conversion efficiency 60-88% (depending on financial tolerance) and removes the water-steam-condensation cycle which is inherently inefficient, large, and while not overly complex, not as "solid state" as direct conversion. Here is a decent 2 page read. http://www.askmar.com/Fusion_files/Dire ... actors.pdf

Bob:
Thanks for the 80KV PIV diode idea; unidirectional semiconductor isolation sounds like a good idea and for 150v penalty seems smart. And yes I have ordered matching ballast resistors as my initial order was one of each, not its two of the target units. I am using Surplus Sales of Nevada, great selection of ballast resistors and very reasonable pricing. I will test 40kohms - 100kohms ranging from 80-200watts, big guys. Right now for testing the 60-65kohm range at 120watts seems fine for my 30kv setup.

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