Power Management: Common UPS Technology
September 13, 2010
This is Chris Matt, Managing Editor of Print & E-Media with Maintenance Solutions magazine. Today's tip is understanding four common uninterruptible power supplies (UPS).
When the time comes to change a UPS, managers have a number of options from which to choose, and the choice will depend on the facility's current equipment and future needs. Common UPS technologies include:
Flywheel UPS. If managers use a UPS in conjunction with a generator system, the flywheel might be a good option. It packs enough inertia to carry the critical loads through a power outage for a short period — normally 10-20 seconds — until the generator has started, stabilized, and picked up the required loads.
True online UPS. This type of UPS — sometimes referred to as double conversion or double-conversion online — provides a high level of reliability for large servers, data centers, and large, sensitive equipment. Under normal operation, it runs continually off the battery via the inverter, and the line power runs the battery charger. For a true online UPS, there is no transfer time upon the loss of utility power.
Standby online hybrid. This UPS — also sometimes referred to as double conversion on demand — is similar to a true online UPS but with higher energy efficiency. The significant difference is standby online hybrid UPS loads are served directly from utility power, as long as the power is within acceptable tolerances.
Line-interactive UPS. This UPS continually conditions and regulates alternating-current utility power to equipment via a power converter. If the utility power fails or falls outside the input range of the power converter, the UPS battery will support the loads via an inverter.
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