UPS

Single phase uninterruptible power supplies (UPS) sit between an AC outlet (i.e., a wall outlet) and an electronic device (such as a computer or phone) to provide power conditioning, back-up protection and distribution for electronic equipment loads and to prevent power disturbances (outages, sags, surges, spikes, noise, etc.) from affecting the performance and life of the electronic device and vital data.

The most important capacity specifications to consider when specifying uninterruptible power supply (UPS), single phase include the volt-amp rating, watt rating and input voltage range. UPS units are rated in volt-amperes (VA) or kilo-VA (kVA). The VA rating is the maximum number of Volts * Amps a unit can deliver. The VA rating is not the same as the power drain (in Watts) of the equipment. The easiest way to find out how many VA is needed is to look at the back of the equipment that is to be protected and note the total number of amps listed for each device. Take the total and multiply it by the nominal voltage (120V) to get the number of VA. For example, a computer and monitor which are both rated at two (2) amps would require 480VA (2A+2A=4A 4Ax120V=480VA). With this rating, at least a 500VA UPS is recommended. The watt rating is specified only if VA Rating is not known (the Watt Rating is less than or equal to VA Rating). The input voltage range is the precise identification of the electrical system is critical in the proper selection and application of a UPS device.