Answer:
There are a variety of factors driving the
adoption of 415/240VAC distribution. First,
distributing at these increased voltages
enables overall efficiency to be enhanced
by eliminating the need for a voltage
transformation along the power path. For
example, in a 415V system, the L-N voltage
is 240V, which is compatible with most all IT
loads. By shifting the UPS output distribution
voltage to 415/240 V three-phase (L-L/
L-N), most of the existing servers today can
be powered with 240V single-phase (L-N)
without any intermediate transformation.
Removing the need for a transformer
streamlines the power path and can increase
efficiency approximately 1.5 percent.
The adoption of a 415/240VAC distribution
model also can yield additional savings at
the device-level in the form of increased
efficiency for server power supplies. As
previously mentioned, today’s power
supplies can handle a wide range of incoming
voltages. Based on the actual voltage being
fed into the power supply, efficiencies can
range from as low as 80 percent (at 100V
nominal) to as much as 94 percent (at 240V
nominal) across all manufacturers.
Furthermore, while the typical efficiency
differential between 240V and 208V gained
at the server power supply today is a relatively
minimal, only 0.3 percent across most of
the load range, the efficiency differential
between 240V and 120V servers can be as
much as 2 percent for a given power supply.
It is this value that often gets overstated by
some manufacturers when comparing 415V
distribution to “traditional methods,” as
there are relatively few servers or peripherals
installed today that are operating at 120V.
Explanation: