12v power supply diodes

[AKHeathen]

ok, almost done building my bench 12v power supply, and want to upgrade the rectifier section later. i pulled the 25a transformer from an old (late 90's) battery charger, and it is set up with a 2-part secondary winding with 2 single large rectifier diodes pressed into a heatsink. there is no part numbers to speak of, but they measure out to .484v and that is all i can get from them.. i want to run it at 12+12, both sides rectified bi-polar, and really want to use the same kind of setup for the diodes for cooling purpose. for now, i just have a pair of 25a universal rectifiers with through-hole mount, like the one i use in my 3a supply, but again, i want them to dissapate heat better, or do you think they will do fine? another thing- i'm going to be doing the same thing again with a much larger supply out of a 200amax charger that shot the diodes years ago, and also runs 12+12, so i'm going to need some nice, heavy duty sink mountable diodes for that, too. any help appreciated, and part numbers would be nice. i'll be placing an order to digikey tonight, or tomorrow, so if i can throw some in there, would be great. thanks- heath-

[Enzo]

How about a plain old 35A bridge? Bolt it to a slab of metal, and voila.

http://www.fairchildsemi.com/ds/GB/GBPC3506.pdf

[AKHeathen]

yah, that's what ended up doing- 40a chicklet bridge, and came up with a heat-sink to bolt to, though i under-estimated the transformerand it wants to run 28v per side, not 15. shoulda known it would do that allowing the secondaries go full cycle, rather than 50%...