NCR 7458 - Manual (Page 73)

Chapter 3: Hardware Service 3-49
Maximum Rated Output Power
The maximum rated output power as defined as the sum of the
products of each nominal voltage and maximum load, which is 300 W
including battery charger output.
UPS
The UPS provides un-interruptible power to all DC outputs in the
event of an AC line interruption, until the support batteries reach a
specified level or until AC power is available again.
Note: The AC convenience outlet is not powered by the UPS during
AC line interruption.
The UPS is used for periods of time ranging from 1 minute to 30
minutes, depending on battery capacity and DC load of the system.