MTBF (Mean Time Between Failures) - Mathematical calculation of the duration of normal operation of a repairable device between failures. The product, expressed in hours, is an indication on the reliability of the device.
UPS (single) - A UPS made up of one single UPS unit (rectifier/charger, inverter and bypass) and a battery.
Reliability - Probability that a device will accomplish a required function under given conditions over a given period of time. Rms value of AC current with harmonics The rms value Yrms of a non-sinusoidal alternating current may be determined on the basis of the individual harmonic currents - where Y is the rms value of the fundamental.
Distortion (individual) - Ratio between the rms value of an nth order harmonic and the rms value of the fundamental.
Constant Current Discharge - A battery discharge regime whereby the current drawn during the discharge remains constant.
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.
Voltage Delay - Time delay for a battery to deliver the required operating voltage after it is placed under load.