Fuse - Device used for cutting off an electrical current in the event of an abusive condition.
Rechargeable (or "Secondary") Battery - A galvanic battery which, after discharge, may be restored to the fully charged state by the passage of an electrical current through the cell in the opposite direction to that of discharge.
Volumetric Energy Density - The ratio of the energy output of a cell or battery to its volume (Wh/L).
Distortion (total) - Ratio between the rms value of all harmonics of a non-sinusoidal alternating periodic value and that of the fundamental. This value may also be expressed as a function of the individual distortion of each harmonic Hn= Yn /Y1.
Power Surge - Voltage above 110% of rated RMS voltage for one or more cycles.
Interference (high-frequency) - High-frequency parasitic current that is either conducted (electrostatic origin) or radiated (electromagnetic origin) by a device.
Percent load - Ratio between the power Pu drawn by the load and the rated output Pn of a UPS system (Pu/Pn). Sometimes referred to as the load factor.
