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Need help with a couple part numbers...

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LAN_403

Killa-X

Fri Aug 01 2014, 04:43AM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

Well, I'm failing to find much luck on google and figured maybe there's some generic system to SCR pucks where someone here could just see it and go OH! That's simple, its ____ volts ____ amps!

So. I have 2 SCR pucks that need some specs. Volts/Amp ratings. I got them donated from a guy who rips apart large UPS systems and other industrial toys. He decided a fellow space in the area is a pain in his butt, so he decided to feed me with his collection. For now...This is what I have.

1) T72H10456DG
2) 104X125DA089

Any idea? Would love to know how to read these to know what their rated, specially if I may be getting more... Also is there an average weight to compress these with? I know my last SCR puck i had to buy 4X 400 pound spring washers making up for 1600 pounds because I had a SCR puck that was specced 1500-2000 pound compression. But then I go online, and I see people just screwing down on bolts with no spring-washers.. making me wonder how do they know they have the right amount of force, that its going to work properly? Compression isnt a problem... I have a ton of 1.5" 7070-T6 aluminum bar stock...

Steve Conner

Fri Aug 01 2014, 09:46AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Those "people just screwing down on bolts" probably don't even know that a puck SCR needs a specific evenly distributed pressure.

Dr. Slack

Fri Aug 01 2014, 11:45AM

Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659

Do you need the pressure just to ensure contact between the external connections and the puck? If so, 'just screwing down bolts' but with a bit of 'engineer's feel' to avoid crushing the thing would probably get you most of the way there. Or does the puck have stuff inside that needs even pressure on the top and bottom faces to maintain its internal integrity?

What's the Z axis thermal expansion coefficient of a puck? If it matches steel bolts reasonably well, then the pressure from plain bolts could stay reasonably constant over temperature changes. Otherwise, you *will* need the compliance of some sort of spring to absorb the movement.

Sulaiman

Fri Aug 01 2014, 12:18PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

The puck has to be compressed for good contact with the silicon.
There's no bonding inside, even the gate connection is a bit of springy metal.

Many puck clamps have an internal 'spring' and fixed height,
so all you have to do is tighten the four bolts and the pressure on the puck will be (near) correct.

...

Fri Aug 01 2014, 03:43PM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

I have had good luck just cranking down on the bolts evenly so that they were about as tight as I could get them (probably about 30-50ft/lbs), although I also did not know any of the ratings for the SCR so I am not sure if I was running it anywhere near its maximum ratings. It was one of the 2" diameter ones, and survived a direct short across a moderate quality 4000uf 400v electrolytic so I was happy.

Killa-X

Sat Aug 02 2014, 06:28AM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

Yeah, these I'm just curious the volts/amp ratings to know if they'll be happy at 500VDC. Regaurdless of the amps, they should be plenty fine dumping 5.5KJ to a strip of foil

Connecting to these hopefully:

In the past I had a SCR puck that was rated 1200V 850A. Same physical size as these pucks I have here. Using 1x1x4 inch aluminum bars, 1/2" bolts, spring-washers etc, i had it loaded to 1850 pounds. That SCR puck was able to handle 1.5KJ 450V short-circuiting to ring launchers, coilguns, foil strips, copper strips, etc. The use here is for a electrothermal gun. I'm just vaporizing foil strips, so its not a high demand short, as theres usually a good amount of volts left after it vaporizes. I made an ETG prototype, crudly, on the lathe awhile back ago. Using this bank at full charge, i shot it off by touching a chicken-stick wire to the contact of the ETG. This obviously makes a big SPARK upon contact -- lots of wasted energy. Yet the crudly made ETG still shot a 1cm long, 5mm diameter wooden "bullet" through 3 soda cans. by the 4th, it rotated enough that the flat 1cm side couldnt penetrate it. So I rebuilt a new one which is a TON more rigid, durable, and safer. Longer barrel ( it was 2 inches ) and I'm looking to replace the old manual contact ( huge losses ) with a SCR puck.

Jrz126

Sat Aug 02 2014, 07:28PM

Registered Member #242 Joined: Thu Feb 23 2006, 11:37PM
Location: Erie PA
Posts: 210

Looks like that 2nd number is a GE part. It's more than likely a custom part number so no specs available. Also the part number will have no obvious relation to ratings.
It's probably ok for 500V.

Killa-X

Sun Aug 03 2014, 04:20AM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

Well, I think my last puck had no datasheet but volts/amps were known ( ebay parts seller ) and If i recall correctly I asked about clamping ages ago on 4HV and was told I'm preeeeeeetty safe hitting between 1500-2000 pounds of clamping. That's where I decided to get spring washers that lay flat when compressed at their rated strength, and was hitting 1850 pounds at maybe 30-40 foot pounds.

Whats a simple way to test for volts? Just start it on a smaller capacitor, like 200J, charge it to 500V, and see how it goes? Or just be a man ( with saftey in mind ) and put it up to the full bank and if it lives it lives..if it detonates during charge it detonates. I would simply case it in a concrete cinder block cell and stand back XD

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