Charger - Device associated with the rectifier and used to supply the battery with the electrical power (DC current) required to recharge and/or float charge the battery, thus ensuring the rated backup time.
Primary Battery - A battery which is not intended to be recharged and is discarded when the battery has delivered all of its electrical energy.
Frequency Variation - A change in frequency of more than 3 Hz.
Ambient Temperature - The average temperature of the surroundings.
Cubicle (single UPS unit) - Cubicle containing a rectifier/charger, an inverter and a bypass. Connected to a battery, it operates alone, forming a single UPS. Compare with Cubicle (parallel UPS unit).
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.
Safety installation - Installation supplying electrical equipment which may have a direct effect on the safety of users and must therefore remain energized even in the event of a mains failure. In general, characteristics concerning the power supply and conditions for transfer to the safety source for such electrical equipment are covered by applicable regulations.