Re: Redundant power supplies

Lasse Langwadt <llc@fonz.dk> wrote:

On 10/27/24 07:54, Don Y wrote:

Most of my boxes have dual power supplies.� Most
don't give me an option as to how they are used/configured;
one shits the bed, the other is there to cover the load.
 
I have always *assumed* they were configured to SHARE the load.
 
I picked up another box that gives me the option of NOT operating
them redundantly (what the hell does the "extra" one do, just
sit around??).� And, when in the redundant configuration,
allows me to choose which is the "primary".
 
This suggests one is carrying the load and the other is switched
in (even if passively) when that one fails.
 
Is there any advantage to this over a "sharing" configuration?

 
I would guess if you wanted to power one of them from a "preferred"
powersource and the other from a another source that you don't want
to load unless you have to
 
 

 
And, why would I ever want to *disable* PFC?
 

 
when you have an UPS that doesn't have sinewave output, they don't
always play nicely with PFC
 

The two best things about equal sharing are that the supplies run cooler
and that you always know that the backup supply is working.

Otherwise you risk cascading failures a la Three Mile Island.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs  Principal Consultant  ElectroOptical Innovations LLC /
Hobbs ElectroOptics  Optics, Electro-optics, Photonics, Analog Electronics