The time that a UPS supplies backup power to electrical appliances while the power supply fails. The backup time unit is one minute and calculates the backup time from when a power failure occurs until the battery is depleted.

Voltage that appears between the line and the neutral of a generator connected in Y and from line to line of a generator connected in delta

In a reusable battery that loses its stored charge, it can be recharged by applying charging current that converts the chemicals in the battery into stored electricity. the battery stores this charge until it is needed again. The charging current is what allows the battery to be used repeatedly.

Total loss of electrical energy. Some literature considers a voltage drop less than 80V, as a blackout, since most electrical equipment will not work below these levels.

Fully automatic voltage regulation in a UPS stabilizes low voltage (boost) and high voltage (buck) to maintain power rating without resorting to battery power when minor power fluctuations occur.