I would like to know what type of bridge rectifier i need to purchase to achieve currents of 30 to 50 amps.

 

How many amps does the load needed?
If the load needs 50 Amps, then you better choose over 50 amps, as 80 or 100 Amps.

You can search on google as - bridge rectifier 80 or 100 amps, you also can search on below web.

http://tw.mouser.com/Semiconductors/Diodes-Rectifiers/Bridge-Rectifiers/_/N-2xpqk

BTW, you still have to care about the rating voltage of bridge rectifier.

 

Like Scott said more than 50 amps!

 

At those currents you might want to consider individual stud mounted diodes.

The MDA3500 is in the ballpark but probably not quite up to 50 A continuous to a resistive load. I've used this before a to supply a couple of stepper motors with 8V @25 A

Edit: This part might be obsolete and no longer available

 

I would like to know what type of bridge rectifier i need to purchase to achieve currents of 30 to 50 amps.

http://www.digikey.com/product-detail/en/MSD50-12/MSD50-12-ND/2260217


It will have to be mounted to a very good heatsink. At 50A continuous current, it will be dissipating something like 100 Watts.