Crest factor (Fc) - Ratio between the peak current value to the rms current value.
Distortion (individual) - Ratio between the rms value of an nth order harmonic and the rms value of the fundamental.
Gravimetric Energy Density - The ratio of the energy output of a cell or battery to its weight (Wh/kg). This term is used interchangeably with specific energy.
Backup time - Time during which the UPS can supply the rated load with nominal-quality power while the mains are down. This time depends on the battery and the efficiency of the UPS. Typical backup ranges from five minutes to several hours.
Redundancy (standby) - UPS configuration in which one or several UPS units operate on stand-by, with no load or only a partial load, and can immediately back up a faulty UPS unit by no-break transfer of the load, carried out by a static switch.
Electromagnetic compatibility - Possibility of a device to operate normally when installed near other devices, given the disturbances emitted by each device and their mutual sensitivities.
Reversal - The changing of the normal polarity of a battery due to overdischarge.
