Re: Redundant Power

[Larry Bolhuis <lbolhuis@xxxxxxxxxx>]

Pretty much the same thing. In order to have two cords you need two 
supplies.  In order for it to be effective at all they must be 
redundant. For example if you did this with a i270 or an i810 that had 
two supplies you would be setting your self up for a failure of the UPS 
*OR* the wall plug failing to drop the system because those power 
supplies are not redundant.

If the supplies are billed as redundant that Must mean that each can do 
all the work if required and without any action by the user. Either of 
them can suddenly be the only one working but the system stays up.

In the case described here the supplies each carry roughly 50% of the 
load so the outlet and the UPS each get half. If the outlet goes dark 
then only the UPS remains to supply both it's current 50% plus the 
outlet's 50%. When there isn't that much headroom on the UPS then the 
UPS shuts off in self protection.

- Larry

ChadB@xxxxxxxxxxxxxxxxxxxx wrote:
> You're talking about splitting the cords between utility and UPS, and not
> about the reduntant power supply, right?
>
>                     
>
> *WARNING* *WARNING* *WARNING*
>
> In this configuration you *MUST* be certain that the UPS is never over
> 50% load! If it's at even 51% when the power fails and the UPS must
> carry all of the load instead of only half it caries now it will drop
> like a stone leaving you completely unprotected and of course unpowered
> as well!!.
>
> The only way to test this for sure is to unplug all the power supplies
> that go into the wall and see if the UPS can stand it!
>
>  - Larry
>
> Chris Bipes wrote: