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UNINTERRUPTIBLE POWER SUPPLIES
Always online
By Alex Emms, Operations
Director, Uninterruptible Power
Supplies Ltd.
www.upspower.co.uk
The importance of a reliable
service partner for UPS installations
Critical ICT loads within data centres rely on UPSs to
protect them from power issues and ensure a continuous
uninterrupted power supply at all times. To live up to this
expectation, UPSs must not only be reliable and resilient
but also backed by a rigorous and well executed planned
maintenance programme. This should include on-site or fast
access to critical spares inventory and a rapid and high-quality
response service to cover emergencies.
Optimising a maintenance programme for a particular
data centre, however, calls for consideration of many issues;
the failure scenarios that must be allowed for, and the
capacity of on-site staff to complement external technicians’
maintenance efforts, or alternatively to create maintenance
problems through operator error. The UPSs’ topology is also a
significant factor.
The maintenance programme’s ability to handle these
issues depends on how well resourced it is, in terms of
technician skills and availability of suitable and correct-
revision components, and documentation and management.
Below, we discuss these maintenance factors, and how to
design a maintenance programme to handle them. Among
other points, this discussion highlights the benefits of
using the original UPS manufacturer (OEM) to provide a
professional maintenance solution.
Routine maintenance
Data centres are continuously populated with facilities staff
who oversee the mechanical and electrical services, so there
are opportunities for those staff to carry out some, but
probably not all, of the routine planned maintenance tasks, if,
and only if, the power system topology incorporates sufficient
‘concurrent maintenance’ capability. Those tasks include
downloading the event logs, set-point monitoring, filter
changes, visual inspection of all connections, general cleaning
and battery cleaning/torque setting. If the concurrent
maintenance capability is dependent upon manual switching
of complete systems, including the UPS for example, then the
correct levels of system training and familiarity exercises must
be regularly carried out.
Non-routine maintenance & failure response
UPSs also require further maintenance tasks, but not so
regularly or routinely. These include:
• Battery load bank and cell impedance measurements
(annual, rising to bi-annual)
• DC capacitor changes
• AC capacitor changes (seven to nine-year intervals)
These non-routine PM tasks and all UPS failure interventions
are infrequent. Emergency interventions – an actual failure
of one or more UPS functions – are so infrequent as to be
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