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Specifying UPS: A Critical Decision
May 21, 2008 - Contact FacilitiesNet Editorial Staff »
This is Chris Matt, Associate Editor of Maintenance Solutions magazine. Today’s tip is specifying the proper UPS system.
Uninterruptible power supplies – or UPS – have become essential in providing reliable operation of critical electronic equipment. Managers’ UPS options include three basic types of systems: passive standby, line interactive, and double conversion.
Passive-standby systems are the least expensive option and provide the lowest level of protection. These off-line systems monitor the incoming power and switch to a battery source when an interruption occurs. While the transfer takes place in milliseconds and is suitable for a number of computer-based applications, the loss of power during the transfer can disrupt the operation of some sensitive electronic equipment.
Line-interactive systems insert an inductor or transformer between the connected equipment and the power source. While line-interactive systems offer more protection than passive-standby, they do not fully isolate the equipment being protected from irregularities in the incoming power. Line-interactive systems offer adequate protection for many common facility applications but not enough protection for those that are mission-critical.
Double-conversion systems are a true online system. Double-conversion systems fully isolate the protected equipment from the power source, eliminating most power disturbances. Double-conversion systems are appropriate for all applications requiring a high level of protection. Their biggest drawback, however, is cost, both the initial cost and the long-term maintenance cost.