# Superconductor???



## bigpagoda (Apr 3, 2016)

Hello, I have about a dozen of these I took out of some VFD's that were in our scrap bin. Fuji calls them superconductors but doesn't give any information on whats inside them. Anyone ever seen or processed these before. I think there must be some PMs in there as the are protected with a sticky cosmoline-like coating. What are they, what should I do with them. I get about 4-5 of these a year but have never taken them apart before. any suggestions would help.


----------



## g_axelsson (Apr 3, 2016)

Probably some high current high voltage switching device. I've seen one similar device but a lot smaller in an UPS. Since I only had once I haven't done any more research on it.

Göran


----------



## Dpetes (Apr 4, 2016)

Partname 7MBR25SA120-01 
Description IGBT Module 
Functional IGBTs (Insulated Gate Bipolar Transistors) 

http://pdf.datasheetcatalog.com/datasheet/fuji/7MBR25SA120-01.pdf


----------



## Smack (Apr 4, 2016)

They would be worth more if they work. There are places that can test them in your area. Go to a machine shop, they will know of a repair place for equipment like that.


----------



## bigpagoda (Apr 8, 2016)

thanks for the link, unfortunately some of them are burnt and they are shock/static sensitive and were buried half disassembled under a lot of other scrap- very little chance they will work. I am curious what the circuits are made of though. the production drawings do not specify the material. any ideas?


----------



## g_axelsson (Apr 8, 2016)

Then test it, a drop of HCl dissolves aluminium, a drop of nitric dissolves silver, copper or palladium and another drop of HCl precipitates silver chloride if it's present.

My bet is on aluminium on the bond wires and possible screen printed silver on the circuit board conductors. But taken into account the power levels of that construction the circuit board might be thick copper with silver plate. Just scratch it and look for red copper beneath the white surface.

If nitric acid dissolves the traces and forms a colorless liquid then test for silver.
If nitric acid dissolves the traces and forms a blue liquid then test for silver traces but the bulk is probably copper.
If nitric acid dissolves the traces and forms a brown liquid then test for silver and then the silver free liquid for palladium.

Göran


----------



## kurtak (Apr 9, 2016)

The heat spreader is a thick heavy piece of nickel plated copper - the bond wires are aluminum - not sure about the circuit traces

Kurt


----------



## Platdigger (Apr 9, 2016)

I guess that is one way to not have to use precious metals. Just encapsulate everything in this
"sticky cosmoline-like coating" hence no oxygen to oxidize.


----------



## johnny309 (Apr 11, 2016)

If they are working parts...try Ebay....it's 100 to 200 USD a piece ...depends on serial number.
The wires are made from pure silver(best conductor) to ensure the high amps.
Trace plating on the ceramics is Pd/Ag(30/70)....ink...
To get out the ...looks like silicone....try a small sample to see if is dissolving in acetone....

P.S.: I almost forgot....they are called IGBT modules....


----------

