SAG

SAG is the acronym for:

SAg is the abbreviation for:

Sag (or Sâg, Șag, Šag) may refer to:

Voltage sag

A voltage sag (U.S. English) or voltage dip (British English) is a short duration reduction in rms voltage which can be caused by a short circuit, overload or starting of electric motors. A voltage sag happens when the rms voltage decreases between 10 and 90 percent of nominal voltage for one-half cycle to one minute. Some references defines the duration of a sag for a period of 0.5 cycle to a few seconds, and longer duration of low voltage would be called a "sustained sag".

Related notions

The term "sag" should not be confused with brownout which is the reduction of voltage for minutes or hours.

The term "transient" as used in power quality is an umbrella term and can refer to sags, but also to swells, dropouts etc.

Swell

Voltage swell is the opposite of voltage sag. Voltage swell, which is a momentary increase in voltage, happens when a heavy load turns off in a power system.

Causes

There are several factors which cause a voltage sag to happen:

Sag (geology)

In geology a sag, or trough, is a depressed, persistent, low area; the opposite of an arch, or ridge, a raised, persistent, high area. The terms sag and arch were used historically to describe very large features, for example, characterizing North America as two arches with a sag between them.

Also, a sag is a former river bed which has been partially filled with debris from glaciation or other natural processes but which is still visible in the surface terrain. Sags formed by the former river beds of large rivers often become the valleys of smaller streams after a change of course by the main river.

Examples of sags include the former continuations of the Grand, Moreau and White rivers in South Dakota in the United States. Before the last ice age these rivers continued eastward past their current confluences with the present course of Missouri River. The sags are prominently visible on the plateau of the Coteau du Missouri, allowing small streams to drain into the Missouri from its eastern side.