A working group was formed within The Green Grid to examine whether the ITIC/CBEMA curve still applies to modern day ICT equipment. The Power Work Group of The Green Grid teamed with the Joint TGG and ECOVA 80 Plus Task Force to place a population of actual ICT power supplies under controled tests aimed at revealing performance of these units against ITIC/CBEMA parameters.
As a part of this investigation, we examined a population of 400W and 1,100W common power supplies from several manufacturers, and subjected them to input power outages of various durations, under 50% and 100% load. The test baseline applied a load to the power supply, representing draw from the ICT equipment it would normally be intalled in. The load was set at 50% and 100% for each power quality test case.
Four signals were instrumented for examination through an oscilloscope. The AC input voltage was monitored in order to show the introduction of the fault. AC current was also monitored, to illustrate attempts by the power supply to recover from the induced interruption. The DC Main voltage was monitored, as the main supply to the ICT equipment from the power supply. Finally, the Power OK signal was monitored. This signal is a discrete indicator to the supported ICT equipment of the state of power availability.
Transient faults of 10mS, 20mS, and 60mS were introduced, in order to test the ITIC/CBEMA thresholds as well as PSU recovery ability, while recording and observing the performance of the power supply under test.
By Bob Landstrom
(This is Part-5 of a 9-part series on a modern assessment of the ITIC/CBEMA curves)