4.0 Principles of operation
4.8 Operation during a utility failure (continued)
of the battery (the battery could be charged faster, but wouldn’t last as long).
Utility voltage sags are temporary amplitude reductions of the normal line voltage level. Utility voltage sags can be caused by local high power demand equipment such as elevators, air conditioners, shop tools and electric heaters. Brownouts, defined as long lasting utility voltage reductions, are sometimes initiated by the power company itself. During the hot season, the utility may choose to reduce the line voltage in order to cope with the huge power require- ments of home and commercial use air conditioners.
Blackouts are defined by a complete loss of power. Often, blackouts are caused by accidents or acts of nature. However, they can also be created by overloaded “branch” circuits (building wiring segregated by fuses or circuit breakers), faulty circuit breakers or even a