With
the recent proliferation of low-cost standby UPS products which claim to
"solve all the ac power problems", a false sense of security
seems to exist among users who purchased and installed these basic
non-isolated UPS for their PCs, fileservers, network/telecommunication
equipment, point-of-sale terminals, etc.
Such a false sense of security and
confidence is often rudely challenged by equipment glitches, crashes,
and malfunctions that persist even after installation of these
non-isolated UPS products. The answer to this unexplainable failure of
UPS to provide 100% protection against ac power problems can be found in
an isolation transformer
based UPS or Line Conditioner.
Experienced electrical engineers have
known this limitation of non-isolated UPS, line conditioners, surge
protection devices and EMI/RFI noise filters for a long time - and their
answer has been a "dedicated circuit" which is a separate ac
wire run all the way to the main electrical panel located next to the
building’s power transformer. Since the high neutral line voltage and
high levels of spikes and transients are caused by devices such as air
conditioners, heaters, elevators, copiers, laser printers, etc.,
bypassing all the sub-panels that feed these "dirty" devices
by installing and using a "dedicated circuit" usually solved
the problems.
However, installation of a dedicated
circuit can be very expensive and time-consuming, especially when it is
a large or high-rise building. Installation of a dedicated circuit also
requires an approval and permit from a licensed professional engineer
(P.E.), the building wiring diagram and the final drawing and work must
be inspected and approved by a local county or city electrical
inspector. The cost of a single dedicated circuit can be several
thousand dollars and may require several weeks (or months) from start to
finish.
The high cost and long installation time
of installing a dedicated circuit can be eliminated by using an
isolation line conditioner or isolation UPS system, however. Because of
the integral isolation transformer, each isolation line conditioner or
UPS qualifies as a "separately derived power source" under
National Electrical Code 250-5D. Isolation conditioners and UPS also
comply with the U.S. federal government’s FIPS Publication 94
requirement of neutral and ground bonding for elimination of any
problems caused by the presence of neutral voltage or common-mode
noise/transients.
Additional
benefits provided by an isolation line conditioner (or UPS):
- Regeneration of power using the
isolation transformer at the point of use means that it is a truly
ideal power source (It is like moving the building transformer to
within a few feet of sensitive equipment). The power from an
isolation transformer is both dedicated
and isolated.
- Multi-stage surge protectors and
EMI/RFI noise filters are also built-in.
- Isolation conditioner sizes ranging
from 90 VA to 5.5 kVA allows optimized performance vs. cost product
selection. UPS size ranges from 400VA to 2,100 VA.
- Installation is immediate and no
permit or approval is required. (Conditioners are also available in
sizes up to 36 kVA, and it is recommended they be installed by a
licensed electrician).
- Cost of the unit is only a small
fraction of a dedicated circuit installation cost.
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