An uninterruptable power source (UPS) is used to calculate whether or not your electrical or IT equipment is capable of running during a power outage. The UPS provides a few minutes of short-term backup power to your equipment using batteries that have stored energy for this very purpose.
A UPS can also address glitches and equipment failure, but remember that it is not usually capable of supporting heavy loads of electricity that may be required by items like fire pumps or cooling equipment. Just as a generator uses diesel fuel to provide power, a UPS uses batteries that must be regularly tested to ensure that they can handle connected appliances.
Read more about how to test a UPS system with a load bank test and why it's important.