3 Phase bridge rectifier, made from 3 single phase rectifiers.

[Bob Edge]

Hi,

I need a 3 phase bridge rectifier that can handle around 15A / Phase.
The limit for fairly inexpensive ones seems to be 35A, higher than this and the price is just not viable for the product.
I know paralleling diodes is not a good idea since one diode will usually take most of the current.
My idea is to use 3 35A single phase rectifiers, with each rectifier having it's AC inputs tied together, which works out cheaper even than the one 3 phase 35A unit.
They will of course be bolted to the chassis of the machine, and have thermal grease, and the duty cycle is less than 10%

Can anyone think of a reason why this is a bad idea?

Regards
Bob.

 

[chuckey]

"35A single phase rectifiers, with each rectifier having it's AC inputs t", so the 35 A rectifiers are bridge rectifiers?. Have you checked their PIV?
Does this mean that the neutral is your output reference. with each phase rectified and then commoned? Every time a rectifier conducts there will be a pulse of neutral current.
Frank

 

[pilko]

Vehicle alternators usually have a 3ph rectifier consisting of 3 diodes mounted on a heat sink ---- here is an example.

https://www.ebay.ca/itm/DELCO-REMY-...ies&hash=item43c06c05c7&vxp=mtr#ht_490wt_1395