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 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

UPS VFI

Symbols

Online double-conversion UPS

In an online double-conversion UPS the load is always supplied by the inverter. The rectifier converts incoming AC to DC, the battery floats on the DC link, and the inverter produces a regulated output that is independent of input voltage and frequency variations. When the input fails, the battery simply takes over the DC link with no transfer.

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

A distinction that matters

An online UPS powers the load through the inverter all the time; a line-interactive UPS passes mains to the load and only inverts during disturbances.

Full reference

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