power distribution solutions for the ProLiant DL580 G2 server

power distribution solutions for the ProLiant DL580 G2 server
3
term
description
g
round leaka
g
e
current
Residual current flow through the grounding conductor, which is
always undesirable. With data processing occurring at ever-
increasing speeds, most IT equipment 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
g
round. Leaka
g
e 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
distribution unit
(PDU)
Rack-mounted component that connects directly to the building’s
AC power infrastructure. The PDU typically provides circuit-
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
(pf)
An efficiency rating that indicates the amount of watts actually
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.
volt-ampere
(VA)
A rating of apparent power (i.e., the amount of AC power that is
available to or can be handled by utility equipment) measured
with a voltmeter and an ammeter. In single-phase systems VA = E
× I, where E = volts, I = current in amperes. In three-phase
systems VA = 1.73 × E × I.
watt (W) A rating of true power consumed by the product and measured
with an input power meter. In single-phase systems W = E x I x pf,
where E = volts, I = current in amperes, and pf = power factor.