Three phase rectifier

[Emach]

I'm looking to cobble together a 3ph DC link rectifier for use on a test bench here at work. The load is a 350VDC 150kW motor drive and I have a 480VAC (closer to 495VAC ph-ph) supply. Doing some quick math that means I am looking at around 315A draw on the 480VAC feed and 428A output from the bridge. My issue comes in when I can't find diode bridges rated above 200A continuous, and those need to have their temp kept below 95 deg C! My dumb question is can I gang two bridge modules together by connecting the two dc - outputs together to the neutral point on the wye side of the isolation transformer? Also does anyone out there in the power world know of a cheap V/I/kW panel mount meter? I am looking to monitor the power going into the drive and compare it to my mechanical output power to take a stab at the efficiency of the system. Thanks!

[gleblanc]

Alright, this is a pet peeve, but... Either use the units for each quantity, or use the name for each quantity. V/A/kW (Volts, Amps, kilo-Watts), or V/I/P (Voltage, current, power). Unfortunately, I haven't got anything even remotely close to useful to suggest here.

[Emach]

Thanks for the suggestions!

[panic mode]

you can parallel two bridges but you will not like it. the problem is to linearise the diodes in order to share the load and this will get ugly. (it means use of 'resistors' in mOhm range. for such current this is more practical to accomplish with pieces of wire/cable). the other way is to build it from discrete diodes but most 400A diodes are quite expensive. another way is to take a closer look at rectifiers that may be hard to find but do handle larger current. try OctoPart.com as search engine. For example check SemiKron products like SEMIX341D16S (stock at allied and also one piece at Newark). http://www.alliedele...px?SKU=70098255