Glossary - HP DL360 - ProLiant - G3 Deployment Manual

HP ProLiant DL360 G3 Server High-Density Deployment

Glossary

Table 1. Glossary of Power Terms
Term Description
High Voltage
180 - 264 VAC (200-240 VAC nominal) supplied to areas where
load requirements are such that high voltage is more economical.
Common in commercial applications in North America, numerous
foreign countries also use this range as the AC appliance
standard.
Inrush Current
A high, momentary current draw occurring when power is first
applied to electrical systems. This current drain is not relative to
the power-on requirements of equipment; it is due to the
capacitive and inductive properties of components in the power
supply.
Keyboard/
Keyboard/video/mouse (KVM) peripherals. A KVM switch is an
accessory that switches a single KVM set between two or more
Video/Mouse
server units.
Ground Residual current flow through the grounding conductor; always
Leakage undesirable. With data processing occurring at ever-increasing
Current speeds, most IT equipment these days includes capacitors in the
power circuits to filter radio frequency (RF) signals to ground.
While effective at filtering RF, these components tend to allow a
small amount of AC current to pass to the ground. Leakage current
is additive, so that as more equipment is connected to the AC
mains, the amount of leakage can increase.
Low Voltage
90 - 132 VAC (100-120 VAC nominal) supplied at utility outlets
in homes and offices. This is the AC appliance standard used in
North America, Latin America, and Japan.
Power Density
The amount (product) of amps and voltage provided to a system
(VA). A 120-VAC 30-amp circuit will deliver a power density of
3600 VA while a 208-VAC 30-amp circuit (single-phase) will
deliver a power density of 6240 VA.
Power Rack-mounted component that connects directly to the building's
Distribution Unit AC power infrastructure. The PDU typically provides circuit-
(PDU) breaker protection for groups of AC outlets into which separate
AC components of the rack are plugged. Some PDU designs offer
primary/secondary switching.
Power Factor An efficiency rating that indicates the amount of watts actually
(Pf) consumed by a load from the volt-amperes delivered to it. The
rating is expressed as either a decimal number between 0 and 1
or percentage of the formula of dividing watts by volt-amperes. A
power factor of 1 indicates that a device receiving 1 VA is
consuming 1 watt.
Power Service
Point at where electrical power enters a building or equipment
room.
Preliminary
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