3 FM quick reads on uninterruptible power supplies
1. The Importance of UPS Maintenance
Even modern facilities that are designed according to codes to provide backup power systems with appropriate levels of redundancy will have a high probability of failure if technicians do not properly test and maintain these essential systems.
The failure of a backup power system in an institutional or commercial facility could cause the loss of productivity, revenue and even human life. As a result of these high stakes, maintenance and engineering managers must ensure they provide a reliable flow of power to support critical systems and equipment, especially in emergencies.
In many facilities, a standby generator system supports crucial life-safety systems, such as egress lighting and fire alarm, that enable occupants to safely evacuate a building. In health care facilities, these systems also support essential life-support and other equipment.
In facilities with critical computer and technology loads, uninterruptible power supplies (UPS) are part of the standby power-distribution system. These systems include auxiliary equipment, such as transfer switches and fuel tanks.
Prior to the testing and maintenance of backup power systems, technicians need to investigate potential locations and environmental causes of failure. Is key equipment located below flood level? Is it located below seismically unsafe objects or in an area with insufficient air flow? Assuming the system's designers and installers resolved any location and environmental issues prior to installation, managers can focus on testing and maintenance.
Just as a chain is only as strong as its weakest link, a standby power-distribution system is only as strong as its weakest link. A 5 megawatt (mW) generator distribution system can fail because of an incorrect fuse, a loose wire connection, or a lack of fuel.
It is important that technicians address all system components both individually and as a system. Standby power systems typically contain cooling, fuel, battery/charging, engine, and distribution subsystems, which all have their own unique testing and maintenance requirements.
2. UPS: A Maintenance Checklist
This is Chris Matt, Managing Editor of Print & E-Media with Maintenance Solutions magazine. Today's tip is a checklist for uninterruptible power supply (UPS) maintenance.
The lifespan of UPS batteries is typically three-five years, depending on conditions and maintenance. At that time, technicians must replace them to ensure the unit operates properly. Keeping tabs on indicators of problems can ensure uninterrupted service to the equipment and facility operations, and, in many cases, a healthier bottom line.
Fortunately, many newer UPS have advanced monitoring systems that provide system status for such items as system voltage, battery back-up time, and battery test schedule.
Many systems can remotely alert technicians if a problem occurs. This information can be especially helpful if technicians monitor the facility remotely. Technicians also must test physical equipment quarterly, semi-annually, or annually using a specific checklist of items to cover. The schedule should include:
• conducting visual inspections for wear and deterioration of battery and insulation components
• cleaning and vacuuming the enclosure
• monitoring the enclosure's temperature and humidity
• performing thermal heat scans, which can indicate hot spots that often are the first sign of component failure
• testing other electrical-system components, such as transfer switches, circuit breakers, and maintenance bypasses.
3. Power Management: Common UPS Technology
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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