UNINTERRUPTIBLE POWER SUPPLIES
33
A look at what constitutes a poor
By Power Control
www.powercontrol.co.uk
When you're looking to invest in a new uninterruptible
power supply, naturally, the focus is on the systems’
functional attributes such as battery autonomy, power
factor, efficiency, reliability and the initial cost. While these
are of course essential, its also important to remember that
uninterruptible power supplies contain fragile electrical
components requiring stable and precise environmental
conditions, specified by each UPS manufacturer, to ensure
maximum longevity.
Avoiding problems
Extreme temperatures are the most common causes of UPS
battery degradation, provoking behaviour that’s incongruent
to their normal specifications. Nearly all uninterruptible
power supply manufacturers will quote a battery operating
temperature tolerance typically between 20-25°C. Placing a
UPS system in an environment which has a temperature not
conducive to its specification will cause the electrochemical
reaction in the battery to quicken. On average, for every 8.3°C
above the recommended temperature, the life of the battery
reduces by 50%.
More often than not heat and humidity go hand in hand.
Moisture in a high voltage environment can have serious
consequences, causing corrosion of UPS cabinets and internal
components, or worse a fire. Again, most UPS manufacturers
will specify the maximum relative humidity of an environment
safe for the UPS, most commonly <95% (non-condensing).
For this reason, it’s recommended that a UPS is not installed
near open windows or areas containing high levels of
moisture.
To prevent overheating, an uninterruptible power supply
requires adequate ventilation and cooling. The powerful fans
UPS environment and how this can
ultimately be avoided...
draw in air from the surrounding environment to cool the
machine down, any dust or corrosive particles in the air will
also be drawn in and sticking to the fan blades. A layer of dust
could cause a significant blockage leading to overheating and
ultimately the UPS system may be at risk of consequential
failure.
Businesses requiring UPS systems that are located near the
coast should take extra precautions when installing. Similarly,
to the adverse effects caused by dust, UPS systems located
near the coast are affected by the sea air. The fans draw in
salty air which crystallises on the printed circuit boards (PCBs)
inside the UPS causing them to corrode and potentially short
circuit.
Assessment is essential
Installing UPS systems into such environments demands a
detailed assessment of the surrounding conditions of the
proposed location. We recommend that the UPS undergoes
specialist treatment which includes the internal circuity on
the UPS having a silicon-based solution sprayed on them,
providing a level of protection against harsh environments.
It’s also recommended that any UPS installed in an
unsettled environment should have a minimum of two
service visits per annum to remove any build-up of dust and
closely monitor the resilience.
Ultimately, we always recommend that prior to installing
a UPS and battery solution, that a room with temperature
control, humidity monitoring, and that contains clean air
is factored into the budget. Neglecting this crucial criteria
can have severe and disastrous consequences on UPS and
battery infrastructure. n
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