To produce a 3 phase bridge rectifier you need 6 diodes connected in 3 series pairs.
There are 3 phase versions of these bridges but as they are generally more expensive than two single phase bridges people don't seem to use them. They may also not be so readily available in many areas.
You can rectify 3 phase with 1 and a half single phase bridges, the rating is then the same as a 3 phase bridge. You have one diode pair left over. This could become a spare pair if you killed another single pair but you would need to choose to blow it up wisely.
Alternatively you can use each bridge as one pair with both diode strings in parallel, with increased but not double the handling current. That way you need 3 units.
If your current is low then 1 and a half units will do. If you need more current then using 3 gives you more in hand.
Personally I would have asked the question another way " pros and cons of using Kbpc's".
They can only carry their claimed current rating on inductive or resistive load when mounted on near infinite heat sinks. Even then I question the crimp connectors.
Using one and a half bridges on a typical heat sink I think it is realistic to expect 10A. Using 3 then perhaps 20A, but there is a penalty from paralleling diodes. In this case with diodes in a package the matching should be good so doubling may about hold.
For real big currents you need lots of these things in parallel and then the de rating does become significant. There are far better ways to rectify large currents and using individual stud mounted diodes is a far more certain and reliable way.
Probably the large 3 phase bridges are also effective but new price is silly compared with diodes. If you find a good price on a 100A 3 phase bridge it will be far better than a heatsink full of tiddly bridges.
Flux
