Eaton 9130

UPSonNet: Most UPS Systems are inadequate to Power Energy Star labeled Servers

by edipp on Jul 1, 2009

Energy Star, a joint program of the U.S. Environmental Protection Agency and U.S. Department of Energy, issued on May 15, 2009, requirements for Computer data center Servers specifications, which according to UPSonNet recent review are not met by more than 90% of North American UPS systems.

Computer Power Supplies draw pulsed current from the mains. The current comprises Fundamental (mains) frequency sinusoidal component and also parasitic higher harmonics which increase input current but do not contribute to the power which the Power Supply delivers.

Volt Ampere figure represents server's input Total Power, is calculated by multiplying input voltage by total input current (including harmonics).
Watt figure represents the Real Power drawn by the server from the utility, or from UPS batteries, and is calculated by multiplying input voltage by the current of the fundamental frequency component.

Power Factor (PF) is defined as Real to...Read More >>