Page 44 - Energize February 2022

TECHNICAL

Industrial UPS systems are essential

to reliable operations

by Mike Rycroft, Energize

Use of UPS systems to supply power to IT and server installations is a well-established practice. Complex
manufacturing processes also require uninterruptible power to ensure continuity of operation, but the requirements
differ substantially from the standard commercial UPS, and careful selection and sizing of systems is necessary to
ensure reliable and safe operation.

n general, the application sector for UPS systems can be broken Environment
into two segments: Information technology (IT) applications and The environment within which an industrial UPS must operate
Iindustrial applications. contains extremes that include:
• Temperature: in the case of a standard UPS, the temperature
Information technology applications of the surrounding environment should not exceed 40° C. The
Commercial UPSs have become associated with IT equipment. The industrial UPS temperature range is broader, from -10 to 55° C.
specifications for IT UPS equipment are not technically demanding • Environment: an industrial UPS must be able to withstand
and typically require only basic safety certification. Data centres dust or water splashing, in places like factories or mines;
in banks, hospitals and insurance companies are examples of described by IP ratings higher than IP7
typical large IT UPS applications. The interruption of AC power to IT • Seismic activity: certified for use in higher seismic activity
equipment may disrupt data processing and telecommunications zones.
but does not create an inherent risk of injury to people or property. • Vibration: the industrial UPS is also engineered to withstand
high degrees of vibration such as those encountered in mining
Industrial applications operations where blasting is a regular occurrence
Industrial applications include critical process control, where
the interruption of AC power could cause dangerous process Output waveforms
instability or cause expensive damage to the production systems. An industrial UPS is required to produce a high-quality sinusoidal
Because of the risk resulting from the loss of control power, UPS waveform free of harmonics. This differs from commercial UPSs
systems intended for industrial applications must be designed where pseudo–sinewave output is often acceptable.
and performance tested to a more rigorous level than commercial
equipment. UPS systems designed for this type of application are Sizing and rating
known as industrial UPSs. Where a commercial UPS is generally required to deliver a
There are also light industrial applications whose processes are constant load and can be rated for this, the industrial UPS can be
not inherently dangerous, even if AC power is interrupted during required to cater for start-up and inrush currents, giving a rating
operation. However, the failure of the UPS to supply continuous AC requirement higher than the average full load rating. Designers
power may result in the loss of finished products or in hundreds will often de-rate components to cater for higher usage.
of man-hours lost in resetting the production equipment.
Pharmaceuticals and the food & beverage industries are examples Configuration
of light industrial classifications. Industrial UPS systems are designed The configuration of the UPS will be determined by the
and performance tested to a more rigorous level than commercial load requirement. The image of an industrial UPS that
systems. 1 normally comes to mind is a large centrally located UPS that
carries the full load of the factory installation. However,
Requirements of an industrial UPS system a centralised unit is vulnerable to distribution failures
Operational requirements of an industrial UPS system differ between the UPS and the application, and many critical
substantially from those of commercial UPS systems. Industrial processes have high availability and uptime requirements
UPS systems are typically equipped with “ruggedised” enclosures, that mean that the UPS needs to be co-located with the
filtering mechanisms and monitoring devices, such that they tend to process; thus a site could have a number of smaller UPS
be larger than standard UPS systems with similar power ratings. A systems installed (Figure 1). These still have to meet
commercial UPS, on the other hand, operates in a closely controlled industrial UPS requirements and compliance systems are
temperature environment. available in the full range of sizes from 10 kVA to 1500 kVA.

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