Current Drain - The current withdrawn from a battery during discharge.
Cell - The basic electrochemical unit used to generate or store electrical energy.
UPS (single) - A UPS made up of one single UPS unit (rectifier/charger, inverter and bypass) and a battery.
Voltage Delay - Time delay for a battery to deliver the required operating voltage after it is placed under load.
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.
UL - Underwriters Laboratories (UL) is a non-governmental, non-profit certification organization in the United States in which not only government authorities are represented, but also consumer groups, "export" services, research, etc. Following certification, a product may bear the UL label.
Reactance (subtransient Uscx %, for generator) - Relative measurement (%) of the internal impedance of an AC generator during harmonic phenomena. This reactance, also called the longitudinal subtransient reactance of the generator, is sometimes identified as X"d. For most common generators, the value ranges between 15 and 20%. It can drop to 12% for optimized systems and to 6% for special devices.