Energy - The output capability of a cell or battery, usually expressed in watt-hours.
Power Surge - Voltage above 110% of rated RMS voltage for one or more cycles.
Redundancy (active) - Parallel UPS configuration in which several UPS units with equal outputs are parallel connected and share the load. In the event one UPS unit fails, the other units pick up its share without any interruption in the supply of power to the load. (back)
Frequency - The repetition of cycles measured in Hz. 60 Hz is the standard frequency in the U.S. 50 Hz is the standard frequency in other parts of the world. 60 Hz = 60 cycles per second.
Load (non-linear) - Load (generally with a switched-mode power supply) generating major harmonic currents. Current wave form is different from voltage wave form. Ohm's law is not applicable. It can be used only with each harmonic.
Cycle Life - The number of cycles under specified conditions which are available from a secondary battery before it fails to meet specified criteria as to performance.
Specific Energy - The ratio of the energy output of a cell or battery to its weight (Wh/kg). This term is used interchangeably with gravimetric energy density.