
IBM System x – UPS3000 Training
© 2003 IBM Corporation
6
October 2007
© 2007 IBM Corporation
Volt-Amps and Watts:
Apparent Power and Real Power
Real Power
Apparent Power
VOLTAGE
TIME
0
+
-
16.67ms.
t
CURRENT
The
Power Factor
is the
Phase Difference
between V and A
UPS needs to be able to provide both the kVA and the kW required by the load-
output p.f. indicates the multiplier from kVAs to kWs
Higher Output p.f. allows the UPS to be used with modern server loads without
having to upgrade to a larger kVA size
VA x PF = W
KVA x PF = KW
. . . The true output
power of a UPS is
measured in watts
While UPSs are
generally measured
in VA . . .