Critical Facility Services



An appropriately selected, connected and maintained UPS provides an instantaneous interval power source for critical loads. Most people are familiar with small portable “plug-in” UPS versions, but when it comes to larger critical loads, substantially larger “hardwired” UPS equipment is available and the Smith & Long Critical Systems Team are here for you as your premier technical contractor of choice for UPS installations, service and ongoing maintenance

There is a wide selection of Uninterruptable Power Supplies on the market to select from and build into your critical power system infrastructure. Your final selection will depend upon your business needs analysis and budget. Traditionally a UPS prime power source has been and continues to be in the form of batteries, however, there is also a growing availability and business case for “flywheel” technology in specific applications.

The general UPS operating principles with respect to design configurations are:

  • Standby UPS – Also referred to as an offline or line-preferred UPS, it continually monitors the connected voltage source for voltage sags or power failures. When either condition is recognized, the UPS will then turn on its inverter (the component that produces output alternating current from the direct current battery source) and supply output power until the sag returns to a safe operating voltage, or the normal power has been restored, or for as long as the battery capacity permits.
  • Line-Interactive UPS – This type contains a battery and inverter that are always connected to the output and have an AVR (Automatic Voltage Regulator) which will boost and buck power during sag and swell (overvoltage) conditions. UPSs with AVRs do not utilize the battery supply as often thereby saving on the life of the battery.  By the “Line-Interactive” definition, a brief power interruption occurs during either type of switching over to the battery, typically 2-4 milliseconds, which is insignificant and acceptable to most loads.
  • Online Double Conversion UPS – In this design, all incoming power is converted to direct current, which charges the batteries and electrically feeds the inverter simultaneously.  The inverter continually produces alternating current to supply the load until the main power deviates from normal or it totally fails, at which point the batteries maintain the needed DC supply to the inverter, thus enabling the load to be electrically fed in a seamless fashion.

The Smith & Long Critical Systems Team want you to know that the potential features and benefits of a UPS do not end with just providing “interim power”, for that is truly the beginning when it comes to the potential of significantly enhancing the quality of power feeding the various loads electrically connected to it. This will help ensure these loads not only continue to operate as designed, but with an added layer of protection to avoid the potential of premature equipment failure due to undesirable voltage anomalies it may experience.

An Important Role in a Bigger Picture – A UPS can act as a standalone device to provide power during a power “brownout” or complete power loss providing much needed time to enable critical systems to be shut down in an appropriate manner until utility power is restored. However, in many business applications such as mission-critical facilities, having unplanned downtime is not a plan at all. In this case, the UPS is interconnected with a generator and ATS power distribution infrastructure. This design scenario provides the necessary “stop-gap” power while the generator starts and ramps up to the designed speed, voltage, and frequency until it is ready to fully support its designed building loading. This interim power source is usually required for approximately ten seconds, all depending on the generator size and specific load characteristics.

Whatever your needs (or perceived needs) areas related to a UPS, the Smith & Long Critical Systems Team are at your service for personal, professional support and advice for systems design and engineering, procurement and installations, as well as ongoing technical support, service, and maintenance.