Side-by-side reference

Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

First referenceCompare with

UPS VFD

Symbols

Offline standby UPS

An offline or standby UPS connects the load directly to mains through a transfer relay. A separate charger keeps the battery topped up, and the inverter starts only when mains fails, at which point the relay transfers the load. Transfer typically takes several milliseconds to around ten milliseconds.

Drawing use: SLD / Schematic
Application: Microgrid systems
Reference family: IEC / IEEE / ANSI

A distinction that matters

An offline UPS gives no correction until it transfers; an online UPS conditions the output continuously.

Full reference

UPS VI

Symbols

Line-interactive UPS

A line-interactive UPS supplies the load from mains in normal operation, using an automatic voltage regulation stage, often a tapped autotransformer, to correct sags and swells. One bidirectional converter charges the battery while mains is present and inverts from the battery when mains fails, with a short transfer of a few milliseconds.

Drawing use: SLD
Application: Microgrid systems
Reference family: IEC / IEEE / ANSI

A distinction that matters

A line-interactive UPS corrects voltage on the mains path; an offline UPS passes mains without correction until it transfers.

Full reference

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.