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UPS Operation Must Be Consistent With Its Environment

by Michael A. Stout, Vice President of Engineering, Falcon Electric, Inc., Power Electronics Technology, Aug 01 2012

Focus:
Commonly available online UPSs are tested and approved for operation over the O°C to 40°C temperature range. But outside this range there are various components within the UPS that can fail or have their performance degraded. The message behind this article is that designers should carefully evaluate UPS temperature specifications when selecting a UPS for harsh environments (and possibly select an extended temperature range unit such as Falcon Electric's SSG RP series.) However, this article may be useful to UPS designers as it identifies temperature-related sources of component failure within a UPS. Tops on this list are the VRLA batteries, which are discussed in some detail, but other vulnerable components such as electrolytic capacitors, ICs and optoisolators are also discussed. Techniques for mitigating the effects of uncontrolled environments such as increased operating efficiency, use of forced air cooling and laminar airflow, insulated housings for the battery and other components, temperature sensing and controls, higher-temp components, and heating elements are discussed. A section on "Why Choose An On-line UPS" explains the differences between off-line, line interactive and on-line UPSs and argues that on-line is best for extreme environments.

What you’ll learn:

How to specify a UPS for an uncontrolled or extreme temperature environment
How to design a UPS for an extreme temperature environment (overview)
How to understand potential sources of component failure for UPSs operating in extreme environments

Notes:
Some of the applications where a UPS may encounter extreme temperatures, which are listed in this article, include natural resource excavation and production (ex. oil drilling), wind and solar power plants, remote communications sites, and extreme settings such as steel mills, foundaries, and high temperature furnaces. Regarding the latter some comments are made at the end of the article on techniques for operating a UPS in these very hot environments.

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