Power source (alternate) - Backup source used in the event of a mains failure. The connection time and the duration of the source depend on the type of source used. (back)
Thevenin generator - For a given load, it is possible to consider the power supply as a voltage generator, referred to as a Thevenin generator, made up of a perfect voltage Uo generator, in series with an internal impedance Zs - n Uo is the voltage measured across the load terminals, given that the load is to be disconnected (load terminals forming an open circuit), n Zs is the equivalent impedance as seen from the load terminals (again considered an open circuit), obtained by short-circuiting the upstream voltage generator(s).
Electrochemical Equivalent - Weight of a substance that is deposited at an electrode when the quantity of electricity which is passed is one coulomb.
Coulomb - The amount of electricity transported by a current of one ampere flowing for one second.
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.
Midpoint Voltage - The voltage of a battery midway in the discharge between the start of the discharge and the end voltage.
Power source (safety) - Power source for loads defined as critical by applicable safety regulations. This supply must not be affected by a mains failure and is generally separate from other supplies.