Sag
Sag turns up in 2 fields: adhesives, electrotechnology. Here is what it means to the people in each one.
Sag in adhesives
An adhesive bead slumping or running down a vertical or overhead surface before it sets.
Sag resistance comes from thixotropy: thickeners such as fumed silica make the paste stiff at rest but thin under shear from a pump or spatula. Non-sag grades hold their bead shape on walls and ceilings; self-leveling grades are made to flow flat. Heat lowers viscosity and makes beads sag more, as does an oversized bead.
"Bead's sagging off the vertical flange, switch to the non-sag version for the side panels."
Sag in electrotechnology
Brief drop in RMS supply voltage, usually to between 10 and 90 percent of nominal, lasting up to about a minute.
A sag is a short reduction in RMS voltage, most often caused by a fault elsewhere on the network or by a large motor starting, lasting from half a cycle to about a minute. It is the most common power quality event and the one that drops out contactors, resets PLCs and trips drives on undervoltage. Events are described by retained voltage and duration and plotted against equipment tolerance curves such as ITIC or SEMI F47. Line crews also use the word for the vertical dip of an overhead conductor between supports, which grows as the wire heats.
"Every time the crusher starts we see a sag to 82 percent on the plant bus and the packaging line drops out."