Network/server UPS systems offer
outstanding power protection, but they shouldn’t stop there. They should also incorporate
high-availability and fault-tolerance features that help you avoid network
downtime, which can cost an average of $70,000 per hour for midsize businesses.
On-line
Operation
Network/server UPS systems that use on-line
operation and continuous double conversion provide the best protection and most
reliable power available for critical systems. The double conversion process
isolates equipment from power problems on the AC line and delivers ideal output
24x7.
Hot-Swappable
Power Modules
Traditional UPS systems require you to
power down and disconnect your equipment during a UPS repair. Before you can
restore productivity, you’ll need a repair technician to install the new UPS
system and you’ll need to reconnect, power up and test all your equipment. That
process can require up to two hours of costly and inconvenient system downtime.
Some network/server UPS systems can
eliminate system downtime during UPS maintenance and repair. They include one
or more hot-swappable power modules and a detachable bypass PDU. You can
completely remove and replace the power modules while the bypass PDU keeps your
critical systems up and running without interruption.
Hot-Swap
PDUs
Hot-swappable power modules are not usually
found on UPS systems smaller than 5,000 VA, but you can make some smaller UPS
systems (≤3,000 VA) hot-swappable by adding an external hot-swap PDU. The
hot-swap PDU, also known as a bypass PDU, includes dual power inputs and a
manual transfer switch. You can use the switch to select between UPS power and
utility bypass power.
Power
Redundancy
Many network/server UPS systems can be configured
to provide redundant backup power, and some models have built-in redundancy.
Models with two hot-swappable power modules automatically provide N+1
redundancy when the connected equipment load is ≤50% of capacity.
(The maximum load for N+1 redundancy is equal to the capacity remaining when
one power module has been removed. That would be 66% for three power modules,
75% for four, 80% for five and so on.) If one of the power modules requires
maintenance, repair or replacement, your equipment still receives conditioned
power and battery backup. All the power modules can also be hot-swapped at once
without interrupting equipment operation, which will be supported by the bypass
power source.
You can provide full backup power
redundancy to devices that have redundant power supplies by connecting each power
supply to a separate UPS. Ideally, the UPS systems should also be connected to
separate supply circuits and utility sources. For single-cord devices that do
not have redundant power supplies, you can connect dual on-line UPS systems to
a PDU that has an automatic transfer switch (ATS). The ATS PDU will switch to
the secondary power source if the primary power source fails.
Wide
Input Voltage Range
Network/server UPS systems that can correct
a wide range of input voltages without switching to battery can reduce battery
wear by as much as 40%. This reduces battery life-cycle costs and ensures that
batteries are more likely to provide reliable service during outages.
Automatic
Bypass
Network/server UPS systems with an
automatic AC bypass route utility power to your equipment and keep it powered if
the UPS experiences an extended overload or internal fault.
Hot-Swappable
Batteries
All internal and external batteries of
network/server UPS systems should be hot-swappable. You can replace hot-swappable
batteries without powering down the UPS system or your equipment.
Overload Capacity Some network/server UPS
systems can handle overloads up to 150% for brief periods to support higher
inrush currents at startup and fluctuating power demands during use. They can
also transfer to bypass dynamically to sustain operation during higher and
longer overloads for extended periods. This capability allows UPS systems to
handle the repeated inrush spikes of heavy inductive loads without shutting
down.
