Power usage information?

["Steve McKay" <steve.mckay@xxxxxxxxxxx>]

We have an iSeries 9406-550 at V5R4.

Every Sunday night at roughly the same time, we get an e-mail from our UPS 
indicating that "The size of the load on the UPS is greater than the rating 
on the UPS."  We are trying to determine what device is causing this 
overage.  Some of the other devices in our computer room can display a graph 
of power usage over the past 24 hours.  Is there something that shows the 
power usage of iSeries over the past few hours that we can use to solve this 
mystery?  If not power usage, is there something that shows that the system 
activated a processor (on its' own) or other component that would cause the 
overage?

(The room is secured by access card, so we know that no one is going into 
the room and plugging in a vacuum cleaner, etc.)

Thanks,

Steve