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

PSI

Symbols

Phase-sequence indicator

A phase-sequence indicator connects to all three phases and shows whether rotation is L1-L2-L3 or reversed. It is used when commissioning motors, generators and supply changes, because wrong rotation reverses motors and prevents correct paralleling.

Drawing use: Schematic
Application: Metering & protection
Reference family: IEC / Manufacturer

A distinction that matters

A phase-sequence indicator only displays rotation; a phase monitoring relay acts on incorrect rotation or loss of phase.

Full reference

PH LOSS

Symbols

Phase-loss monitoring relay

A phase-loss relay supervises the presence of the specified phases in a three-phase system. The drawing identifies the monitored source and output used by control or protection logic.

Drawing use: SLD / Schematic
Application: Metering & protection
Reference family: Manufacturer

A distinction that matters

Phase loss is different from phase reversal or current unbalance.

Full reference

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